CommentCrew-threat-apt1

Hunt Hypothesis

CommentCrew-threat-apt1 detects potential adversary behavior involving suspicious comment creation or modification in Azure resources, which may indicate reconnaissance or persistence activities. SOC teams should proactively hunt for this behavior to identify early-stage threats and prevent lateral movement or data exfiltration in their Azure Sentinel environment.

YARA Rule

rule GLOOXMAIL_APT1
{

    meta:
        author = "AlienVault Labs"
        info = "CommentCrew-threat-apt1"
        
    strings:
        $s1 = "Kill process success!" wide ascii
        $s2 = "Kill process failed!" wide ascii
        $s3 = "Sleep success!" wide ascii
        $s4 = "based on gloox" wide ascii
        $pdb = "glooxtest.pdb" wide ascii

    condition:
        all of ($s*) or $pdb
}

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 5 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: Scheduled system backup using Veeam Backup & Replication
  Filter/Exclusion: process.name != "vbm" OR process.name != "vbackup.exe"

• Scenario: Admin performing a PowerShell script to clean up temporary files
  Filter/Exclusion: process.name != "powershell.exe" OR process.args NOT LIKE "*Cleanup-TempFiles*"

• Scenario: SQL Server Agent Job running a routine maintenance task
  Filter/Exclusion: process.name != "sqlagent.exe" OR process.args NOT LIKE "*MaintenanceJob*"

• Scenario: Windows Task Scheduler executing a legitimate system update check
  Filter/Exclusion: process.name != "schtasks.exe" OR process.args NOT LIKE "*UpdateCheck*"

• Scenario: Docker container running a legitimate application with a comment in the log
  Filter/Exclusion: process.name != "docker" OR process.args NOT LIKE "*run*"