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Verclsid.exe Threat Detection

Detecting abuse of verclsid.exe for proxy execution and defense evasion in Windows environments.

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Originally published on Red Canary Blog
Read the full article: Verclsid.exe Threat Detection

What is Verclsid.exe?

verclsid.exe is a legitimate Windows binary used to verify COM class IDs. Like many Windows utilities, it can be abused for:

  • Proxy execution (T1218)
  • Defense evasion
  • Bypassing application whitelisting
  • Living off the land

The Abuse Technique

Adversaries can use verclsid.exe to:

  1. Execute arbitrary COM objects
  2. Load malicious DLLs
  3. Bypass security controls
  4. Evade detection

Example Usage

verclsid.exe /S /C {CLSID}

Detection Strategies

Process Execution

Monitor for unusual verclsid.exe execution:

  • Rare process execution
  • Unusual parent processes
  • Command-line patterns
  • Execution from unexpected locations

Command-Line Analysis

Look for:

  • /S and /C flags
  • Suspicious CLSIDs
  • Unusual arguments
  • Encoded parameters

Network Activity

Verclsid.exe normally doesn’t make network connections:

  • Outbound connections
  • DNS queries
  • HTTP/HTTPS traffic

Child Processes

Monitor for unexpected child processes spawned by verclsid.exe.

Splunk Detection

index=sysmon EventCode=1 Image="*\\verclsid.exe"
| where NOT match(ParentImage, "(?i)svchost\.exe|services\.exe")
| stats count by Computer, ParentImage, CommandLine

Sysmon Configuration

<ProcessCreate onmatch="include">
  <Image condition="end with">verclsid.exe</Image>
</ProcessCreate>

Mitigation

  • Application whitelisting (AppLocker/WDAC)
  • Monitor for rare binary execution
  • Restrict COM object execution
  • Implement attack surface reduction rules

Context Matters

Not all verclsid.exe execution is malicious. Consider:

  • Parent process
  • Command-line arguments
  • Execution frequency
  • User context

Read the full analysis: Verclsid.exe Threat Detection

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