CrypKeyV61XDLLCrypKeyCanadaInc

Hunt Hypothesis

This detection identifies the presence of the CrypKey Canada Inc. DLL component to verify legitimate cryptographic operations or uncover potential supply chain compromises involving this specific library. Proactive hunting is essential in Azure Sentinel to distinguish between expected business usage and anomalous deployment patterns that could indicate a stealthy adversary leveraging trusted third-party components for lateral movement or data exfiltration.

YARA Rule

rule CrypKeyV61XDLLCrypKeyCanadaInc
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 83 3D [4] 00 75 34 68 [4] E8 }

condition:
		$a0 at pe.entry_point
}

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 1 string patterns in its detection logic.

• Source Rule

False Positive Guidance

Here are 4 specific false positive scenarios for the CrypKeyV61XDLLCrypKeyCanadaInc detection rule, along with suggested filters to mitigate them:

• Scenario: Automated Deployment of CrypKey Hardware Security Module (HSM) Drivers via SCCM/Intune

  • Context: During scheduled patch cycles or new workstation onboarding, the IT Operations team deploys the CrypKeyV61X.dll as part of a standard driver package for hardware encryption tokens. This often triggers the rule when the deployment agent (e.g., Microsoft Endpoint Configuration Manager) extracts and registers the DLL in the %SystemRoot%\System32 or vendor-specific directory.
  • Suggested Filter: Create an exclusion based on the Parent Process being ccmexec.exe (SCCM Agent) or Microsoft.Windows.Search.exe (Intune Management Extension), combined with a file path constraint ensuring the DLL resides in C:\Program Files\CrypKey\Drivers\.

• Scenario: Execution of Legacy Financial Reporting Scripts by Finance Department

  • Context: The Finance team utilizes a custom PowerShell script (ReportGenerator.ps1) that leverages the CrypKey SDK to digitally sign quarterly tax documents. This script runs nightly via Windows Task Scheduler and loads CrypKeyV61X.dll to interface with physical USB security keys, triggering the detection during the scheduled window (e.g., 02:00 – 04:00 AM).
  • Suggested Filter: Implement a time-based exclusion for the specific Scheduled Task Name (Finance_Signing_Job) and restrict the rule to only alert if the process originates from C:\Users\Finance_Admin\AppData\Local\CrypKey\ rather than generic user temp folders.

• Scenario: Endpoint Protection (EDR) Self-Scanning of Vendor