Cerberus

Hunt Hypothesis

This hypothesis posits that adversaries are establishing persistent, low-noise footholds within the Azure environment by leveraging the “Cerberus” mechanism to maintain continuous access while evading standard alert thresholds. The SOC team should proactively hunt for this behavior in Azure Sentinel to identify subtle indicators of compromise before they escalate into high-severity incidents, ensuring early detection of stealthy lateral movement or data exfiltration attempts.

YARA Rule

rule Cerberus : RAT memory
{
	meta:
		description = "Cerberus"
		author = "Jean-Philippe Teissier / @Jipe_"
		date = "2013-01-12"
		filetype = "memory"
		version = "1.0" 

	strings:
		$checkin = "Ypmw1Syv023QZD"
		$clientpong = "wZ2pla"
		$serverping = "wBmpf3Pb7RJe"
		$generic = "cerberus" nocase

	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

Here are 5 specific false positive scenarios for the Cerberus detection rule in an enterprise environment, including suggested filters and exclusions:

• Automated Patch Management Deployments

  • Scenario: The Windows Update Agent or third-party tools like SCCM (System Center Configuration Manager) or Ivanti trigger mass file modifications and service restarts across hundreds of endpoints simultaneously. These activities often mimic the “lateral movement” or “unauthorized configuration change” signatures that Cerberus monitors, particularly when updating system binaries in C:\Windows\System32.
  • Filter/Exclusion: Create a whitelist for the specific Service Accounts used by these tools (e.g., DOMAIN\SCCM-Deploy-Svc) and exclude file paths matching known patch directories (e.g., C:\Windows\SoftwareDistribution or C:\Program Files\Ivanti).

• Scheduled Backup and Data Archiving Jobs

  • Scenario: Enterprise backup solutions like Veeam, Commvault, or Azure Backup Agent perform nightly snapshots. These jobs generate high-volume file I/O, temporary file creation, and process spawning that can be misinterpreted as data exfiltration or suspicious script execution by the Cerberus logic.
  • Filter/Exclusion: Exclude traffic and process activity originating from backup service accounts (e.g., DOMAIN\Veeam-Backup-Agnt) during defined maintenance windows (e.g., 02:00–06:00 UTC). Additionally, filter out file extension changes specific to backup formats (.vbk, .vrb, .btr).

• Identity Management and Group Policy Updates

  • Scenario: Automated scripts run by Microsoft Entra ID (Azure AD) or on-premises Active Directory tools perform routine attribute synchronization, password resets, or Group