Detects Havex Windows process executable from memory dump

Hunt Hypothesis

This hunt targets adversaries executing Havex malware by identifying its unique process signatures within memory dumps to uncover stealthy infections that may evade traditional file-based scanning. Proactively hunting for this behavior in Azure Sentinel is critical because it enables the SOC team to detect early-stage command-and-control communications and lateral movement attempts before they escalate into significant data exfiltration events.

YARA Rule

rule SANS_ICS_Cybersecurity_Challenge_400_Havex_Memdump : memory
	{
	meta:
		description = "Detects Havex Windows process executable from memory dump"
		date = "2015-12-2"
		author = "Chris Sistrunk"
		hash = "8065674de8d79d1c0e7b3baf81246e7d"
	strings:
		$magic = { 4d 5a }	
	
	        $s1 = "~tracedscn.yls" fullword wide
		$s2 = "[!]Start" fullword wide
		$s3 = "[+]Get WSADATA" fullword wide
		$s4 = "[-]Can not get local ip" fullword wide
		$s5 = "[+]Local:" fullword wide
		$s6 = "[-]Threads number > Hosts number" fullword wide
		$s7 = "[-]Connection error" fullword wide
		
		$x1 = "bddd4e2b84fa2ad61eb065e7797270ff.exe" fullword wide
	condition:
	    $magic at 0 and ( 3 of ($s*) or $x1 )
}

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 9 string patterns in its detection logic.

• Source Rule

False Positive Guidance

Here are 4 specific false positive scenarios for the Havex Windows process executable detection rule, including suggested filters and exclusions:

• Antivirus Real-Time Scanning & Memory Analysis

  • Scenario: Enterprise Endpoint Protection suites (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint) frequently inject their own scanning engines into running processes to perform memory integrity checks. These tools often load Havex-like signatures or behavioral modules directly into the process space of critical services, triggering a “process executable from memory dump” alert when the AV engine scans a legitimate application like sqlservr.exe or spoolsv.exe.
  • Filter/Exclusion: Exclude alerts where the parent process is known security software (e.g., csagent.exe, MsMpEng.exe) and the target process belongs to the “Trusted Applications” allow-list. Additionally, filter for events containing specific AV-related command-line arguments (e.g., /scan-memory or -integrity-check).

• Scheduled System Backup and Snapshot Tasks

  • Scenario: Automated backup solutions such as Veeam Agent, Commvault, or Windows Server Backup create memory snapshots of running services to ensure data consistency during backups. When these tools dump the memory state of a database server (e.g., mysqld.exe or oracle.exe) to verify transaction logs, the detection logic may misinterpret the snapshot creation activity as the Havex malware loading its executable module from memory.
  • Filter/Exclusion: Correlate alerts with scheduled task execution times defined in Group Policy or Task Scheduler (e.g., “VeeamBackupJob”). Create an exclusion rule for events occurring during known maintenance windows where the source IP is a backup server and the target process is part of the database tier.

• Patch Management and Software Deployment Agents

  • Scenario: During enterprise-wide patching