huntrule

Suspicious UAC Bypass via CMSTP INF Auto-Install

PremiumReviewedSigma · High · v1
Product
windows
Category
process_creation
Author
HuntRule
Published
2026-05-12
Updated
2026-08-28
AnalysisDetection

ATT&CK techniques

Priv Esc → Defense Evasion

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule detects execution of cmstp.exe with the auto-install switch pointing to an INF file, a technique used to bypass User Account Control and execute arbitrary commands at high integrity. The Sliver C2 framework and multiple threat actors abuse this living-off-the-land binary to elevate privileges while evading defenses. Detecting it early helps stop attacker privilege escalation before further post-exploitation activity.

Reporting behind it

Related detections9 linkedT1548.002 — drag to rearrange
Suspicious UAC Bypass by Disabling Admin Consent Prompt via registry_set
Malicious Cloud Atlas UAC Bypass via fodhelper (via process_creation)
Suspicious computerdefaults.exe Spawning Child Process
Suspicious UAC Bypass via control.exe App Paths or Shell Open Command Hijack
Malicious UAC Bypass via COMAutoApprovalList Registry Modification (via registry_set)
Suspicious UAC Bypass via COMAutoApprovalList Registry Modification (via registry_set)
Malicious UAC Bypass via explorer.exe NOUACCHECK Argument
Suspicious UAC Bypass via ms-settings Shell Command Hijack (via registry_set)
Suspicious UAC Weakening via ConsentPromptBehaviorAdmin Disable by Winos (via registry_set)
Suspicious UAC Bypass via CMSTP INF Auto-Install
Pivot detection · T1548.002 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.