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 APT1_WEBC2_CSON
{

    meta:
        author = "AlienVault Labs"
        info = "CommentCrew-threat-apt1"
        
    strings:
        $httpa1 = "/Default.aspx?INDEX=" wide ascii
        $httpa2 = "/Default.aspx?ID=" wide ascii
        $httpb1 = "Win32" wide ascii
        $httpb2 = "Accept: text*/*" wide ascii
        $exe1 = "xcmd.exe" wide ascii
        $exe2 = "Google.exe" wide ascii

    condition:
        1 of ($exe*) and 1 of ($httpa*) and all of ($httpb*)
}

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.

• Source Rule

False Positive Guidance

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

• Scenario: Admin performing a Windows Update or Group Policy refresh
  Filter/Exclusion: process.name != "wuauclt.exe" or process.name != "gupdate.exe"

• Scenario: Running a PowerShell script for routine system maintenance or log cleanup
  Filter/Exclusion: process.name != "powershell.exe" or script.name != "Cleanup-Logs.ps1"

• Scenario: Using SQL Server Agent to run a scheduled job for database maintenance
  Filter/Exclusion: process.name != "sqlagent.exe" or process.name != "sqlservr.exe"

• Scenario: Executing a Windows Task Scheduler job for user account management or password reset
  Filter/Exclusion: process.name != "schtasks.exe" or task.name != "UserAccountMaintenance"