Note: This advisory uses the MITRE ATT&CK for Enterprise framework, version 11. See the MITRE ATT&CK Tactics and Techniques section for a table of the threat actors’ activity mapped to MITRE ATT&CK® tactics and techniques with corresponding mitigation and/or detection recommendations.
Overview
In April 2022, CISA conducted retrospective analysis using EINSTEIN—an FCEB-wide intrusion detection system (IDS) operated and monitored by CISA—and identified suspected APT activity on an FCEB organization’s network. CISA observed bi-directional traffic between the network and a known malicious IP address associated with exploitation of the Log4Shell vulnerability (CVE-2021-44228) in VMware Horizon servers. In coordination with the FCEB organization, CISA initiated threat hunting incident response activities; however, prior to deploying an incident response team, CISA observed additional suspected APT activity. Specifically, CISA observed HTTPS activity from IP address
CISA assessed that this traffic indicated a confirmed compromise based on the successful callback to the indicator and informed the organization of these findings; the organization investigated the activity and found signs of compromise. As trusted-third party reporting associated Log4Shell activity from
From mid-June through mid-July 2022, CISA conducted an onsite incident response engagement and determined that the organization was compromised as early as February 2022, by likely Iranian government-sponsored APT actors who installed XMRig crypto mining software. The threat actors also moved laterally to the domain controller, compromised credentials, and implanted Ngrok reverse proxies.
Threat Actor Activity
In February 2022, the threat actors exploited Log4Shell [T1190] for initial access [TA0001] to the organization’s unpatched VMware Horizon server. As part of their initial exploitation, CISA observed a connection to known malicious IP address
The actors’ exploit payload ran the following PowerShell command [T1059.001] that added an exclusion rule to Windows Defender [T1562.001]:
powershell try{Add-MpPreference -ExclusionPath 'C:\'; Write-Host 'added-exclusion'} catch {Write-Host 'adding-exclusion-failed' }; powershell -enc "$BASE64 encoded payload to download next stage and execute it"
The exclusion rule allowlisted the entire
WinRing0x64.sys – XMRig Miner driverwuacltservice.exe – XMRig Minerconfig.json – XMRig miner configurationRuntimeBroker.exe – Associated file. This file can create a local user account [T1136.001] and tests for internet connectivity by pinging8.8.8.8 [T1016.001]. The exploit payload created a Scheduled Task [T1053.005] that executedRuntimeBroker.exe daily asSYSTEM . Note: By exploiting Log4Shell, the actors gained access to a VMware service account with administrator and system level access. The Scheduled Task was namedRuntimeBrokerService.exe to masquerade as a legitimate Windows task.
See MAR 10387061-1.v1 for additional information, including IOCs, on these four files.
After obtaining initial access and installing XMRig on the VMWare Horizon server, the actors used RDP [T1021.001] and the built-in Windows user account
- PsExec – a Microsoft signed tool for system administrators.
- Mimikatz – a credential theft tool.
- Ngrok – a reverse proxy tool for proxying an internal service out onto an Ngrok domain, which the user can then access at a randomly generated subdomain at
*.ngrok[.]io . CISA has observed this tool in use by some commercial products for benign purposes; however, this process bypasses typical firewall controls and may be a potentially unwanted application in production environments. Ngrok is known to be used for malicious purposes.[1]
The threat actors then executed Mimikatz on VDI-KMS to harvest credentials and created a rogue domain administrator account [T1136.002]. Using the newly created account, the actors leveraged RDP to propagate to several hosts within the network. Upon logging into each host, the actors manually disabled Windows Defender via the Graphical User Interface (GUI) and implanted Ngrok executables and configuration files. The threat actors were able to implant Ngrok on multiple hosts to ensure Ngrok’s persistence should they lose access to a machine during a routine reboot. The actors were able to proxy [T1090] RDP sessions, which were only observable on the local network as outgoing HTTPS port 443 connections to
Once the threat actors established a deep foothold in the network and moved laterally to the domain controller, they executed the following PowerShell command on the Active Directory to obtain a list of all machines attached to the domain [T1018]:
Powershell.exe get-adcomputer -filter * -properties * | select name,operatingsystem,ipv4address >
The threat actors also changed the password for the local administrator account [T1098] on several hosts as a backup should the rogue domain administrator account get detected and terminated. Additionally, the threat actor was observed attempting to dump the Local Security Authority Subsystem Service (LSASS) process [T1003.001] with task manager but this was stopped by additional anti-virus the FCEB organization had installed.
MITRE ATT&CK TACTICS AND TECHNIQUES
See table 1 for all referenced threat actor tactics and techniques in this advisory, as well as corresponding detection and/or mitigation recommendations. For additional mitigations, see the Mitigations section.
| Initial Access | |||
| Technique Title | ID | Use | Recommendations |
| Exploit Public-Facing Application | The actors exploited Log4Shell for initial access to the organization’s VMware Horizon server. | Mitigation/Detection: Use a firewall or web-application firewall and enable logging to prevent and detect potential Log4Shell exploitation attempts [M1050]. Mitigation: Perform regular vulnerability scanning to detect Log4J vulnerabilities and update Log4J software using vendor provided patches [M1016],[M1051]. | |
| Execution | |||
| Technique Title | ID | Use | Recommendation |
| Command and Scripting Interpreter: PowerShell | The actors ran PowerShell commands that added an exclusion rule to Windows Defender. The actors executed PowerShell on the AD to obtain a list of machines on the domain. | Mitigation: Disable or remove PowerShell for non-administrative users [M1042],[M1026] or enable code-signing to execute only signed scripts [M1045]. Mitigation: Employ anti-malware to automatically detect and quarantine malicious scripts [M1049]. | |
| Persistence | |||
| Technique Title | ID | Use | Recommendations |
| Account Manipulation | The actors changed the password for the local administrator account on several hosts. | Mitigation: Use multifactor authentication for user and privileged accounts [M1032]. Detection: Monitor events for 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 [DS0002]. | |
| Create Account: Local Account | The actors’ malware can create local user accounts. | Mitigation: Configure access controls and firewalls to limit access to domain controllers and systems used to create and manage accounts. Detection: Monitor executed commands and arguments for actions that are associated with local account creation, such as net user /add , useradd, and dscl -create [DS0017]. Detection: Enable logging for new user creation [DS0002]. | |
| Create Account: Domain Account | The actors used Mimikatz to create a rogue domain administrator account. | Mitigation: Configure access controls and firewalls to limit access to domain controllers and systems used to create and manage accounts. Detection: Enable logging for new user creation, especially domain administrator accounts [DS0002]. | |
| Scheduled Task/Job: Scheduled Task | The actors’ exploit payload created Scheduled Task RuntimeBrokerService.exe, which executed RuntimeBroker.exe daily as SYSTEM. | Mitigation: 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 [M1028]. Detection: Monitor for newly constructed processes and/or command-lines that execute from the svchost.exe in Windows 10 and the Windows Task Scheduler taskeng.exe for older versions of Windows [DS0009] Detection: Monitor for newly constructed scheduled jobs by enabling the Microsoft-Windows-TaskScheduler/Operational setting within the event logging service [DS0003]. | |
| Valid Accounts: Default Accounts | The actors used built-in Windows user account DefaultAccount. | Mitigation: Change default usernames and passwords immediately after the installation and before deployment to a production environment [M1027]. Detection: Develop rules to monitor logon behavior across default accounts that have been activated or logged into [DS0028]. | |
| Defense Evasion | |||
| Technique Title | ID | Use | Recommendations |
| Impair Defenses: Disable or Modify Tools
| The actors added an exclusion rule to Windows Defender. The tool allowlisted the entire c:\drive, enabling the actors to bypass virus scans for tools they downloaded to the c:\drive. The actors manually disabled Windows Defender via the GUI. | Mitigation: Ensure proper user permissions are in place to prevent adversaries from disabling or interfering with security services. [M1018]. Detection: Monitor for changes made to Windows Registry keys and/or values related to services and startup programs that correspond to security tools such as HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender [DS0024]. Detection: Monitor for telemetry that provides context for modification or deletion of information related to security software processes or services such as Windows Defender definition files in Windows and System log files in Linux [DS0013]. Detection: Monitor processes for unexpected termination related to security tools/services [DS0009]. | |
| Indicator Removal on Host: File Deletion | The actors removed malicious file mde.ps1 from the dis. | Detection: Monitor executed commands and arguments for actions that could be utilized to unlink, rename, or delete files [DS0017]. Detection: Monitor for unexpected deletion of files from the system [DS0022]. | |
| Credential Access | |||
| Technique Title | ID | Use | Recommendations |
| OS Credential Dumping: LSASS Memory | The actors were observed trying to dump LSASS process. | Mitigation: 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 [M1043] Mitigation: On Windows 10, enable Attack Surface Reduction (ASR) rules to secure LSASS and prevent credential stealing [M1040]. Mitigation: Ensure that local administrator accounts have complex, unique passwords across all systems on the network [M1027]. Detection: 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. [DS0009]. Detection: Monitor executed commands and arguments that may attempt to access credential material stored in the process memory of the LSASS [DS0017]. | |
| Credentials from Password Stores | The actors used Mimikatz to harvest credentials. | Mitigation: Organizations may consider weighing the risk of storing credentials in password stores and web browsers. If system, software, or web browser credential disclosure is a significant concern, technical controls, policy, and user training may be used to prevent storage of credentials in improper locations [M1027]. Detection: Monitor for processes being accessed that may search for common password storage locations to obtain user credentials [DS0009]. Detection: Monitor executed commands and arguments that may search for common password storage locations to obtain user credentials [DS0017]. | |
| Discovery | |||
| Technique Title | ID | Use | Recommendations |
| Remote System Discovery | The actors executed a PowerShell command on the AD to obtain a list of all machines attached to the domain. | Detection: Monitor executed commands and arguments that 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 [DS0017]. Detection: Monitor for newly constructed network connections associated with pings/scans that 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 [DS0029]. Detection: Monitor for newly executed processes that can be used to discover remote systems, such as ping.exe and tracert.exe, especially when executed in quick succession [DS0009]. | |
| System Network Configuration Discovery: Internet Connection Discovery | The actors’ malware tests for internet connectivity by pinging 8.8.8.8. | Mitigation: Monitor executed commands, arguments [DS0017] and executed processes (e.g., tracert or ping) [DS0009] that may check for internet connectivity on compromised systems. | |
| Lateral Movement | |||
| Technique Title | ID | Use | Recommendations |
| Remote Services: Remote Desktop Protocol | The actors used RDP to move laterally to multiple hosts on the network. | Mitigation: Use MFA for remote logins [M1032]. Mitigation: Disable the RDP service if it is unnecessary [M1042]. Mitigation: Do not leave RDP accessible from the internet. Enable firewall rules to block RDP traffic between network security zones within a network [M1030]. Mitigation: Consider removing the local Administrators group from the list of groups allowed to log in through RDP [M1026]. Detection: Monitor for user accounts logged into systems associated with RDP (ex: Windows EID 4624 Logon Type 10). Other factors, such as access patterns (ex: multiple systems over a relatively short period of time) and activity that occurs after a remote login, may indicate suspicious or malicious behavior with RDP [DS0028]. | |
| Command and Control | |||
| Technique Title | ID | Use | Recommendations |
| Proxy | The actors used Ngrok to proxy RDP connections and to perform command and control. | Mitigation: Traffic to known anonymity networks and C2 infrastructure can be blocked through the use of network allow and block lists [M1037]. Detection: Monitor and analyze traffic patterns and packet inspection associated to protocol(s) that do not follow the expected protocol standards and traffic flows (e.g., extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure) [DS0029]. | |
| Ingress Tool Transfer | The actors downloaded malware and multiple tools to the network, including PsExec, Mimikatz, and Ngrok. | Mitigation: Employ anti-malware to automatically detect and quarantine malicious scripts [M1049].
| |
INCIDENT RESPONSE
If suspected initial access or compromise is detected based on IOCs or TTPs in this CSA, CISA encourages organizations to assume lateral movement by threat actors and investigate connected systems and the DC.
CISA recommends organizations apply the following steps before applying any mitigations, including patching.
- Immediately isolate affected systems.
- Collect and review relevant logs, data, and artifacts. Take a memory capture of the device(s) and a forensic image capture for detailed analysis.
- Consider soliciting support from a third-party incident response organization that can provide subject matter expertise to ensure the actor is eradicated from the network and to avoid residual issues that could enable follow-on exploitation.
- Report incidents to CISA via CISA’s 24/7 Operations Center (
This email address is being protected from spambots. You need JavaScript enabled to view it. or 888-282-0870) or your local FBI field office, or FBI’s 24/7 Cyber Watch (CyWatch) at (855) 292-3937 or by e-mail atThis email address is being protected from spambots. You need JavaScript enabled to view it. .
Note: This advisory uses the MITRE ATT&CK for Enterprise framework, version 11. See the MITRE ATT&CK Tactics and Techniques section for a table of the threat actors’ activity mapped to MITRE ATT&CK® tactics and techniques with corresponding mitigation and/or detection recommendations.
Overview
In April 2022, CISA conducted retrospective analysis using EINSTEIN—an FCEB-wide intrusion detection system (IDS) operated and monitored by CISA—and identified suspected APT activity on an FCEB organization’s network. CISA observed bi-directional traffic between the network and a known malicious IP address associated with exploitation of the Log4Shell vulnerability (CVE-2021-44228) in VMware Horizon servers. In coordination with the FCEB organization, CISA initiated threat hunting incident response activities; however, prior to deploying an incident response team, CISA observed additional suspected APT activity. Specifically, CISA observed HTTPS activity from IP address
CISA assessed that this traffic indicated a confirmed compromise based on the successful callback to the indicator and informed the organization of these findings; the organization investigated the activity and found signs of compromise. As trusted-third party reporting associated Log4Shell activity from
From mid-June through mid-July 2022, CISA conducted an onsite incident response engagement and determined that the organization was compromised as early as February 2022, by likely Iranian government-sponsored APT actors who installed XMRig crypto mining software. The threat actors also moved laterally to the domain controller, compromised credentials, and implanted Ngrok reverse proxies.
Threat Actor Activity
In February 2022, the threat actors exploited Log4Shell [T1190] for initial access [TA0001] to the organization’s unpatched VMware Horizon server. As part of their initial exploitation, CISA observed a connection to known malicious IP address
The actors’ exploit payload ran the following PowerShell command [T1059.001] that added an exclusion rule to Windows Defender [T1562.001]:
powershell try{Add-MpPreference -ExclusionPath 'C:\'; Write-Host 'added-exclusion'} catch {Write-Host 'adding-exclusion-failed' }; powershell -enc "$BASE64 encoded payload to download next stage and execute it"
The exclusion rule allowlisted the entire
WinRing0x64.sys – XMRig Miner driverwuacltservice.exe – XMRig Minerconfig.json – XMRig miner configurationRuntimeBroker.exe – Associated file. This file can create a local user account [T1136.001] and tests for internet connectivity by pinging8.8.8.8 [T1016.001]. The exploit payload created a Scheduled Task [T1053.005] that executedRuntimeBroker.exe daily asSYSTEM . Note: By exploiting Log4Shell, the actors gained access to a VMware service account with administrator and system level access. The Scheduled Task was namedRuntimeBrokerService.exe to masquerade as a legitimate Windows task.
See MAR 10387061-1.v1 for additional information, including IOCs, on these four files.
After obtaining initial access and installing XMRig on the VMWare Horizon server, the actors used RDP [T1021.001] and the built-in Windows user account
- PsExec – a Microsoft signed tool for system administrators.
- Mimikatz – a credential theft tool.
- Ngrok – a reverse proxy tool for proxying an internal service out onto an Ngrok domain, which the user can then access at a randomly generated subdomain at
*.ngrok[.]io . CISA has observed this tool in use by some commercial products for benign purposes; however, this process bypasses typical firewall controls and may be a potentially unwanted application in production environments. Ngrok is known to be used for malicious purposes.[1]
The threat actors then executed Mimikatz on VDI-KMS to harvest credentials and created a rogue domain administrator account [T1136.002]. Using the newly created account, the actors leveraged RDP to propagate to several hosts within the network. Upon logging into each host, the actors manually disabled Windows Defender via the Graphical User Interface (GUI) and implanted Ngrok executables and configuration files. The threat actors were able to implant Ngrok on multiple hosts to ensure Ngrok’s persistence should they lose access to a machine during a routine reboot. The actors were able to proxy [T1090] RDP sessions, which were only observable on the local network as outgoing HTTPS port 443 connections to
Once the threat actors established a deep foothold in the network and moved laterally to the domain controller, they executed the following PowerShell command on the Active Directory to obtain a list of all machines attached to the domain [T1018]:
Powershell.exe get-adcomputer -filter * -properties * | select name,operatingsystem,ipv4address >
The threat actors also changed the password for the local administrator account [T1098] on several hosts as a backup should the rogue domain administrator account get detected and terminated. Additionally, the threat actor was observed attempting to dump the Local Security Authority Subsystem Service (LSASS) process [T1003.001] with task manager but this was stopped by additional anti-virus the FCEB organization had installed.
MITRE ATT&CK TACTICS AND TECHNIQUES
See table 1 for all referenced threat actor tactics and techniques in this advisory, as well as corresponding detection and/or mitigation recommendations. For additional mitigations, see the Mitigations section.
| Initial Access | |||
| Technique Title | ID | Use | Recommendations |
| Exploit Public-Facing Application | The actors exploited Log4Shell for initial access to the organization’s VMware Horizon server. | Mitigation/Detection: Use a firewall or web-application firewall and enable logging to prevent and detect potential Log4Shell exploitation attempts [M1050]. Mitigation: Perform regular vulnerability scanning to detect Log4J vulnerabilities and update Log4J software using vendor provided patches [M1016],[M1051]. | |
| Execution | |||
| Technique Title | ID | Use | Recommendation |
| Command and Scripting Interpreter: PowerShell | The actors ran PowerShell commands that added an exclusion rule to Windows Defender. The actors executed PowerShell on the AD to obtain a list of machines on the domain. | Mitigation: Disable or remove PowerShell for non-administrative users [M1042],[M1026] or enable code-signing to execute only signed scripts [M1045]. Mitigation: Employ anti-malware to automatically detect and quarantine malicious scripts [M1049]. | |
| Persistence | |||
| Technique Title | ID | Use | Recommendations |
| Account Manipulation | The actors changed the password for the local administrator account on several hosts. | Mitigation: Use multifactor authentication for user and privileged accounts [M1032]. Detection: Monitor events for 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 [DS0002]. | |
| Create Account: Local Account | The actors’ malware can create local user accounts. | Mitigation: Configure access controls and firewalls to limit access to domain controllers and systems used to create and manage accounts. Detection: Monitor executed commands and arguments for actions that are associated with local account creation, such as net user /add , useradd, and dscl -create [DS0017]. Detection: Enable logging for new user creation [DS0002]. | |
| Create Account: Domain Account | The actors used Mimikatz to create a rogue domain administrator account. | Mitigation: Configure access controls and firewalls to limit access to domain controllers and systems used to create and manage accounts. Detection: Enable logging for new user creation, especially domain administrator accounts [DS0002]. | |
| Scheduled Task/Job: Scheduled Task | The actors’ exploit payload created Scheduled Task RuntimeBrokerService.exe, which executed RuntimeBroker.exe daily as SYSTEM. | Mitigation: 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 [M1028]. Detection: Monitor for newly constructed processes and/or command-lines that execute from the svchost.exe in Windows 10 and the Windows Task Scheduler taskeng.exe for older versions of Windows [DS0009] Detection: Monitor for newly constructed scheduled jobs by enabling the Microsoft-Windows-TaskScheduler/Operational setting within the event logging service [DS0003]. | |
| Valid Accounts: Default Accounts | The actors used built-in Windows user account DefaultAccount. | Mitigation: Change default usernames and passwords immediately after the installation and before deployment to a production environment [M1027]. Detection: Develop rules to monitor logon behavior across default accounts that have been activated or logged into [DS0028]. | |
| Defense Evasion | |||
| Technique Title | ID | Use | Recommendations |
| Impair Defenses: Disable or Modify Tools
| The actors added an exclusion rule to Windows Defender. The tool allowlisted the entire c:\drive, enabling the actors to bypass virus scans for tools they downloaded to the c:\drive. The actors manually disabled Windows Defender via the GUI. | Mitigation: Ensure proper user permissions are in place to prevent adversaries from disabling or interfering with security services. [M1018]. Detection: Monitor for changes made to Windows Registry keys and/or values related to services and startup programs that correspond to security tools such as HKLM:\SOFTWARE\Policies\Microsoft\Windows Defender [DS0024]. Detection: Monitor for telemetry that provides context for modification or deletion of information related to security software processes or services such as Windows Defender definition files in Windows and System log files in Linux [DS0013]. Detection: Monitor processes for unexpected termination related to security tools/services [DS0009]. | |
| Indicator Removal on Host: File Deletion | The actors removed malicious file mde.ps1 from the dis. | Detection: Monitor executed commands and arguments for actions that could be utilized to unlink, rename, or delete files [DS0017]. Detection: Monitor for unexpected deletion of files from the system [DS0022]. | |
| Credential Access | |||
| Technique Title | ID | Use | Recommendations |
| OS Credential Dumping: LSASS Memory | The actors were observed trying to dump LSASS process. | Mitigation: 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 [M1043] Mitigation: On Windows 10, enable Attack Surface Reduction (ASR) rules to secure LSASS and prevent credential stealing [M1040]. Mitigation: Ensure that local administrator accounts have complex, unique passwords across all systems on the network [M1027]. Detection: 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. [DS0009]. Detection: Monitor executed commands and arguments that may attempt to access credential material stored in the process memory of the LSASS [DS0017]. | |
| Credentials from Password Stores | The actors used Mimikatz to harvest credentials. | Mitigation: Organizations may consider weighing the risk of storing credentials in password stores and web browsers. If system, software, or web browser credential disclosure is a significant concern, technical controls, policy, and user training may be used to prevent storage of credentials in improper locations [M1027]. Detection: Monitor for processes being accessed that may search for common password storage locations to obtain user credentials [DS0009]. Detection: Monitor executed commands and arguments that may search for common password storage locations to obtain user credentials [DS0017]. | |
| Discovery | |||
| Technique Title | ID | Use | Recommendations |
| Remote System Discovery | The actors executed a PowerShell command on the AD to obtain a list of all machines attached to the domain. | Detection: Monitor executed commands and arguments that 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 [DS0017]. Detection: Monitor for newly constructed network connections associated with pings/scans that 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 [DS0029]. Detection: Monitor for newly executed processes that can be used to discover remote systems, such as ping.exe and tracert.exe, especially when executed in quick succession [DS0009]. | |
| System Network Configuration Discovery: Internet Connection Discovery | The actors’ malware tests for internet connectivity by pinging 8.8.8.8. | Mitigation: Monitor executed commands, arguments [DS0017] and executed processes (e.g., tracert or ping) [DS0009] that may check for internet connectivity on compromised systems. | |
| Lateral Movement | |||
| Technique Title | ID | Use | Recommendations |
| Remote Services: Remote Desktop Protocol | The actors used RDP to move laterally to multiple hosts on the network. | Mitigation: Use MFA for remote logins [M1032]. Mitigation: Disable the RDP service if it is unnecessary [M1042]. Mitigation: Do not leave RDP accessible from the internet. Enable firewall rules to block RDP traffic between network security zones within a network [M1030]. Mitigation: Consider removing the local Administrators group from the list of groups allowed to log in through RDP [M1026]. Detection: Monitor for user accounts logged into systems associated with RDP (ex: Windows EID 4624 Logon Type 10). Other factors, such as access patterns (ex: multiple systems over a relatively short period of time) and activity that occurs after a remote login, may indicate suspicious or malicious behavior with RDP [DS0028]. | |
| Command and Control | |||
| Technique Title | ID | Use | Recommendations |
| Proxy | The actors used Ngrok to proxy RDP connections and to perform command and control. | Mitigation: Traffic to known anonymity networks and C2 infrastructure can be blocked through the use of network allow and block lists [M1037]. Detection: Monitor and analyze traffic patterns and packet inspection associated to protocol(s) that do not follow the expected protocol standards and traffic flows (e.g., extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure) [DS0029]. | |
| Ingress Tool Transfer | The actors downloaded malware and multiple tools to the network, including PsExec, Mimikatz, and Ngrok. | Mitigation: Employ anti-malware to automatically detect and quarantine malicious scripts [M1049].
| |
INCIDENT RESPONSE
If suspected initial access or compromise is detected based on IOCs or TTPs in this CSA, CISA encourages organizations to assume lateral movement by threat actors and investigate connected systems and the DC.
CISA recommends organizations apply the following steps before applying any mitigations, including patching.
- Immediately isolate affected systems.
- Collect and review relevant logs, data, and artifacts. Take a memory capture of the device(s) and a forensic image capture for detailed analysis.
- Consider soliciting support from a third-party incident response organization that can provide subject matter expertise to ensure the actor is eradicated from the network and to avoid residual issues that could enable follow-on exploitation.
- Report incidents to CISA via CISA’s 24/7 Operations Center (
This email address is being protected from spambots. You need JavaScript enabled to view it. or 888-282-0870) or your local FBI field office, or FBI’s 24/7 Cyber Watch (CyWatch) at (855) 292-3937 or by e-mail atThis email address is being protected from spambots. You need JavaScript enabled to view it. .
