huntrule

Malicious UAC Bypass via mscfile Handler Hijack (via registry_set)

PremiumReviewedSigma · High · v1
Product
windows
Category
registry_set
Author
HuntRule
Published
2026-05-31
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 a command being written under HKCU Classes\mscfile\shell\open\command, the registry hijack eventvwr.exe follows to auto-elevate an attacker process while bypassing UAC. The mscfile handler hijack is a privilege-escalation technique tracked in the Red Canary Threat Detection Report. Detecting this modification surfaces a UAC-bypass preparation.

Reporting behind it

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Malicious UAC Bypass via mscfile Handler Hijack (via registry_set)
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.