Modified (packed) version of Windows Credential Editor

Hunt Hypothesis

This detection targets adversaries who modify or pack the legitimate Windows Credential Editor to obscure malicious activities and evade signature-based defenses by altering its binary structure. Proactively hunting for this behavior in Azure Sentinel is critical because attackers often leverage trusted system utilities like CredEdit.exe to execute credential theft or lateral movement while blending into normal administrative traffic.

YARA Rule

rule WCE_Modified_1_1014 {
	meta:
		description = "Modified (packed) version of Windows Credential Editor"
		author = "Florian Roth"
		hash = "09a412ac3c85cedce2642a19e99d8f903a2e0354"
		score = 70
	strings:
		$s0 = "LSASS.EXE" fullword ascii
		$s1 = "_CREDS" ascii
		$s9 = "Using WCE " 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 5 specific false positive scenarios for the Modified (Packed) Version of Windows Credential Editor detection rule, including suggested filters and exclusions:

• Scenario: Deployment via Microsoft Endpoint Configuration Manager (MECM/SCCM)

  • Context: The IT team packages the crededit.exe utility into a custom .msp or .msi installer to distribute it across 500+ endpoints. This packaging process often repacks the executable, changing its hash and structure compared to the original vendor version.
  • Filter/Exclusion: Create an exclusion based on the Process Image Path matching C:\Program Files\Microsoft Configuration Manager\ or the Parent Process Name being ccmsetup.exe. Alternatively, whitelist the specific file hash of the packaged installer used in the deployment.

• Scenario: Automated Onboarding Script Execution via PowerShell

  • Context: A scheduled onboarding job runs a PowerShell script (NewUserSetup.ps1) that invokes the Credential Editor to pre-populate domain credentials for new hires. The script calls the tool from a shared network location or a temporary staging folder, where the file might be stored in a “packed” state by an upstream build pipeline (e.g., Jenkins or Azure DevOps).
  • Filter/Exclusion: Exclude events where the Parent Process Name is powershell.exe AND the Command Line contains arguments referencing the specific onboarding script path. Additionally, filter out processes running under the context of a known service account (e.g., DOMAIN\OnboardingSvc).

• Scenario: Third-Party Password Management Agent Integration

  • Context: An enterprise password management solution (such as BeyondTrust, CyberArk, or Thycotic) installs a local agent that utilizes the Windows Credential Editor to sync vault credentials. The vendor’s installer