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 adversarial activity and prevent further compromise in their Azure Sentinel environment.

YARA Rule

rule ccrewSSLBack1
{

    meta:
        author = "AlienVault Labs"
        info = "CommentCrew-threat-apt1"
        
    strings:
        $a = "!@#%$^#@!" wide ascii
        $b = "64.91.80.6" 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 2 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: Scheduled System Maintenance Job
  Description: A legitimate scheduled task runs a script that includes a comment with the string “Crew” or “APT1” as part of a log message or script documentation.
  Filter/Exclusion: process.name != "schtasks.exe" OR process.name != "task scheduler" or script.name != "maintenance_script.ps1"

• Scenario: Admin Task for User Management
  Description: An administrator is using PowerShell or a command-line tool to create or modify user accounts, and the script includes a comment referencing “Crew” or “APT1” for internal documentation.
  Filter/Exclusion: process.name != "powershell.exe" OR script.name != "user_management.ps1"

• Scenario: Log File Parsing or Analysis Tool
  Description: A log analysis tool (e.g., Splunk, ELK, or Graylog) processes logs and includes a comment with “Crew” or “APT1” in its configuration or log output.
  Filter/Exclusion: process.name != "splunkd.exe" OR process.name != "logstash" OR process.name != "graylog-server"

• Scenario: Backup or Archive Job with Metadata Comments
  Description: A backup job (e.g., using Veeam, Acronis, or Windows Backup) includes a comment in the backup log or metadata that references “Crew” or “APT1” as part of the job name or description.
  Filter/Exclusion: process.name != "veeam.exe" OR process.name != "wbadmin.exe" OR process.name != "acronis.exe"

• Scenario: Internal Security Tool or SIEM Configuration
  Description: A security tool (e.g., Microsoft Defender, CrowdStrike, or QRadar) includes a comment in its configuration or rule set