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

Hunt Hypothesis

This detection identifies adversaries leveraging legacy hacking tools to modify the gina.dll or gina.reg configuration, a technique often used to establish persistence and intercept user authentication processes on Windows systems. Proactive hunting for this behavior in Azure Sentinel is critical because modifications to these core login components can silently enable credential theft or man-in-the-middle attacks that traditional signature-based defenses might overlook due to the tool’s age.

YARA Rule

rule sig_238_gina {
	meta:
		description = "Disclosed hacktool set (old stuff) - file gina.reg"
		author = "Florian Roth"
		date = "23.11.14"
		score = 60
		hash = "324acc52566baf4afdb0f3e4aaf76e42899e0cf6"
	strings:
		$s0 = "\"gina\"=\"gina.dll\"" fullword ascii
		$s1 = "REGEDIT4" fullword ascii
		$s2 = "[HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Winlogon]" 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 3 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.reg detection rule, along with suggested filters and exclusions:

• Scenario: Legacy Group Policy Deployment of Login Scripts

  • Context: The IT Operations team deploys a legacy login script via Active Directory Group Policy that modifies the gina.dll or creates a companion .reg file to customize the Windows logon screen (e.g., adding custom banners or redirecting specific users). This often triggers when the policy refreshes on domain-joined workstations.
  • Suggested Filter/Exclusion: Create an exclusion for files created by the System account within the C:\Windows\System32\GroupPolicy\Machine\Scripts directory, specifically targeting filenames ending in .reg that are modified during standard policy refresh windows (e.g., 09:00–17:00).

• Scenario: Scheduled Maintenance by Endpoint Management Tools (SCCM/Intune)

  • Context: Enterprise Configuration Manager (SCCM) or Microsoft Intune runs a nightly scheduled task to update the local registry for legacy applications that rely on gina.dll hooks. The automation service writes a new configuration file named gina.reg as part of its deployment package before applying changes.
  • Suggested Filter/Exclusion: Exclude alerts where the parent process is ccmexec.exe (SCCM) or Microsoft.IntuneManagementAgent.exe, and the source path matches known management directories like C:\ProgramData\Microsoft\MCCM or C:\Windows\System32\ccm.

• Scenario: Third-Party Identity Provider Installation/Update

  • Context: Organizations using legacy Single Sign-On (SSO) solutions, such as Okta Classic Agent or CyberArk Endpoint Privilege Manager, often