Disclosed hacktool set (old stuff) - file gina.dll

Hunt Hypothesis

This hunt hypothesis targets adversaries leveraging legacy hacktools to replace or inject malicious code into gina.dll, a critical Windows authentication component often used for credential theft and persistence. Proactively hunting this behavior in Azure Sentinel is essential because modifications to such core system files can indicate early-stage compromise that may evade standard signature-based detection, allowing attackers to establish a foothold before broader impact occurs.

YARA Rule

rule gina_zip_Folder_gina {
	meta:
		description = "Disclosed hacktool set (old stuff) - file gina.dll"
		author = "Florian Roth"
		date = "23.11.14"
		score = 60
		hash = "e0429e1b59989cbab6646ba905ac312710f5ed30"
	strings:
		$s0 = "NEWGINA.dll" fullword ascii
		$s1 = "LOADER ERROR" fullword ascii
		$s3 = "WlxActivateUserShell" fullword ascii
		$s6 = "WlxWkstaLockedSAS" fullword ascii
		$s13 = "WlxIsLockOk" fullword ascii
		$s14 = "The procedure entry point %s could not be located in the dynamic link library %s" fullword ascii
		$s16 = "WlxShutdown" fullword ascii
		$s17 = "The ordinal %u could not be located in the dynamic link library %s" fullword ascii
	condition:
		all 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 8 string patterns in its detection logic.

• Source Rule

False Positive Guidance

Here are 4 specific false positive scenarios for the Disclosed hacktool set (old stuff) - file gina.dll detection rule, including suggested filters and exclusions:

• Scenario: Scheduled Windows Update Maintenance

  • Context: The Windows Update service (wuauserv) or a third-party patching solution like Microsoft Endpoint Configuration Manager (SCCM) performs routine updates during maintenance windows. These processes often replace or update system DLLs in the C:\Windows\System32 directory, including gina.dll, to apply security patches or feature updates.
  • Filter/Exclusion: Create an exclusion for file modification events where the parent process is svchost.exe (specifically the wuauserv service) or the SCCM agent (ccmsetup.exe) and the target path matches C:\Windows\System32\gina.dll.

• Scenario: Legacy Authentication Module Deployment

  • Context: In environments utilizing legacy authentication methods (such as older versions of Citrix Workspace, Okta Advanced Server Access, or custom RADIUS integrations), administrators deploy updated authentication modules. These tools often inject a new version of gina.dll to handle the Graphical Identification and Authentication (GINA) interface, triggering the rule upon deployment via Group Policy or manual installation scripts.
  • Filter/Exclusion: Exclude events where the process name corresponds to known enterprise identity management tools (e.g., okta.exe, ctxsvc.exe) and the file hash of the new gina.dll matches a known “good” baseline stored in your SIEM’s asset inventory.

• Scenario: Automated System Health Checks via PowerShell

  • Context: IT Operations teams run scheduled PowerShell scripts (e.g., SystemHealthCheck.ps1) to verify the integrity of critical system files. These scripts may