CommentCrew-threat-apt1

Hunt Hypothesis

CommentCrew-threat-apt1 detects potential adversary behavior involving suspicious comment-based PowerShell scripts that may be used for initial access or command and control. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate early-stage threat activity associated with this adversary group.

YARA Rule

rule MoonProject
{

    meta:
        author = "AlienVault Labs"
        info = "CommentCrew-threat-apt1"
       
    strings:
        $a = "Serverfile is smaller than Clientfile" wide ascii
        $b = "\\M tools\\" wide ascii
        $c = "MoonDLL" wide ascii
        $d = "\\M tools\\" wide ascii

  condition:
        any 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 4 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: Scheduled system maintenance using PowerShell scripts for log cleanup
  Filter/Exclusion: process.parent_process != "powershell.exe" OR process.parent_process.contains("task scheduler")

• Scenario: Admin performing Windows Update via Group Policy Management Console (GPMC)
  Filter/Exclusion: process.name != "wusa.exe" OR process.parent_process.contains("gpmc.exe")

• Scenario: Database backup job using SQL Server Agent executing T-SQL scripts
  Filter/Exclusion: process.name != "sqlservr.exe" OR process.parent_process.contains("sqlagent.exe")

• Scenario: IT staff using Windows Task Scheduler to run PowerShell scripts for user account management
  Filter/Exclusion: process.parent_process.contains("schtasks.exe") OR process.name != "powershell.exe"

• Scenario: System administrator using Sysmon (Microsoft Syslog Monitor) to monitor and log system events
  Filter/Exclusion: process.name != "sysmon.exe" OR process.parent_process.contains("explorer.exe")