Detects malware by Chinese APT PLA Unit 78020 - Specific Rule - msictl.exe

Hunt Hypothesis

Adversaries associated with Chinese APT PLA Unit 78020 may use msictl.exe as part of their malware deployment tactics. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify potential advanced persistent threat activity early.

YARA Rule

rule Unit78020_Malware_1  
{

    meta:
        description = "Detects malware by Chinese APT PLA Unit 78020 - Specific Rule - msictl.exe"
        author = "Florian Roth"
        reference = "http://threatconnect.com/camerashy/?utm_campaign=CameraShy"
        date = "2015-09-24"
        hash = "a93d01f1cc2d18ced2f3b2b78319aadc112f611ab8911ae9e55e13557c1c791a"
   
    strings:
        $s1 = "%ProgramFiles%\\Internet Explorer\\iexplore.exe" fullword ascii
        $s2 = "msictl.exe" fullword ascii
        $s3 = "127.0.0.1:8080" fullword ascii
        $s4 = "mshtml.dat" fullword ascii
        $s5 = "msisvc" fullword ascii
        $s6 = "NOKIAN95/WEB" fullword ascii
   
    condition:
        uint16(0) == 0x5a4d and filesize < 160KB and 4 of them
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

Microsoft Defender for Endpoint — Custom indicators / advanced hunting
Email Gateway — Attachment scanning
File Share Monitoring — Periodic scanning of shared drives
YARA CLI — Manual threat hunting on endpoints

This rule contains 6 string patterns in its detection logic.

References

False Positive Guidance

Scenario: Legitimate System Maintenance Task
Description: The msictl.exe process is used by a legitimate system maintenance tool, such as Microsoft’s System Maintenance Scheduler, to perform routine disk cleanup or system optimization.
Filter/Exclusion: Check the process parent process (e.g., task scheduler or services.exe) and verify if the file path is within a known trusted directory (e.g., C:\Windows\System32).
Scenario: Scheduled Job for Software Updates
Description: A scheduled task runs msictl.exe as part of a software update or patching process, such as through Microsoft Endpoint Manager or Windows Update.
Filter/Exclusion: Filter by the task name or command line arguments that include known update-related keywords (e.g., update, patch, install).
Scenario: Admin Task for Log File Analysis
Description: An administrator uses a custom script or tool that invokes msictl.exe to analyze log files or perform forensic analysis on system events.
Filter/Exclusion: Exclude processes initiated by user accounts with administrative privileges and check for presence of known admin tools in the command line (e.g., PowerShell, cmd.exe).
Scenario: Third-Party Software Dependency
Description: A third-party application (e.g., a security tool or enterprise management software) includes msictl.exe as a dependency for its operation.
Filter/Exclusion: Check the file’s digital signature and verify if it is signed by a trusted vendor. Exclude processes running from non-standard directories (e.g., C:\Program Files\).
Scenario: Malware Analysis Environment
Description: In a malware analysis sandbox, msictl.exe is executed as part of a controlled environment to analyze suspected malicious files.