Generic Rule to detect the Enfal Malware

Hunt Hypothesis

The Enfal Malware is likely being executed through suspicious process creation or fileless techniques that evade standard detection. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate advanced persistent threats before they cause significant damage.

YARA Rule

rule Enfal_Malware_Backdoor {
	meta:
		description = "Generic Rule to detect the Enfal Malware"
		author = "Florian Roth"
		date = "2015/02/10"
		super_rule = 1
		hash0 = "6d484daba3927fc0744b1bbd7981a56ebef95790"
		hash1 = "d4071272cc1bf944e3867db299b3f5dce126f82b"
		hash2 = "6c7c8b804cc76e2c208c6e3b6453cb134d01fa41"
		score = 60
	strings:
		$mz = { 4d 5a }
			
		$x1 = "Micorsoft Corportation" fullword wide
		$x2 = "IM Monnitor Service" fullword wide
		
		$s1 = "imemonsvc.dll" fullword wide
		$s2 = "iphlpsvc.tmp" fullword
		
		$z1 = "urlmon" fullword
		$z2 = "Registered trademarks and service marks are the property of their respec" wide		
		$z3 = "XpsUnregisterServer" fullword
		$z4 = "XpsRegisterServer" fullword
		$z5 = "{53A4988C-F91F-4054-9076-220AC5EC03F3}" fullword
	condition:
		( $mz at 0 ) and 
		( 
			1 of ($x*) or 
			( all of ($s*) and all of ($z*) )
		)
}

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 10 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Scenario: A system administrator is using PowerShell to automate the deployment of a legitimate software update.
  Filter/Exclusion: Check for the presence of known administrative tools or scripts in the command line context (e.g., Get-Command -Name Update-Software or PS1 files signed by a trusted publisher).

• Scenario: A scheduled job runs Task Scheduler to perform routine system maintenance, such as disk cleanup or log rotation.
  Filter/Exclusion: Exclude tasks that are associated with known system maintenance tasks (e.g., Cleanup-SystemLogs or DiskCleanup), or filter by the task name and execution context.

• Scenario: A developer is using Wireshark to capture network traffic for analysis, and the tool is generating alerts due to unusual packet patterns.
  Filter/Exclusion: Exclude processes running under the Wireshark executable or filter by process name (wireshark.exe), or check for the presence of a valid capture filter.

• Scenario: A database administrator is running a SQL Server Agent Job that executes stored procedures for data backups.
  Filter/Exclusion: Filter by the SQL Server process ID or check for the presence of known backup-related stored procedures or job names.

• Scenario: A user is running a Windows Defender scan that temporarily triggers alerts due to heuristic analysis of benign files.
  Filter/Exclusion: Exclude processes running under Windows Defender or filter by the presence of Microsoft Defender Antivirus in the process name or parent process.