huntrule

Windows MSIInstaller EventID 1033 PoC File Takeover String Match (InstallerFileTakeOver/CVE-2021-41379)

Alert on Windows MSI installer EventID 1033 with event data containing 'test pkg', consistent with PoC activity for CVE-2021-41379.

FreeReviewedSigma · High · v5
Product
windows
Service
application
Author
Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2021-11-22
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Initial Access

  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 flags a Windows Installer activity where the MSI installer provider (MsiInstaller) emits EventID 1033 and the event data contains the specific string "test pkg" associated with an InstallerFileTakeOver proof-of-concept for CVE-2021-41379. Attackers may use PoC tooling to validate or trigger local privilege escalation paths by abusing vulnerable installer behavior. Detection relies on Windows application logs capturing MsiInstaller EventID 1033 entries and matching the embedded event data substring.

Reporting behind it

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Windows MSIInstaller EventID 1033 PoC File Takeover String Match (InstallerFileTakeOver/CVE-2021-41379)
Pivot detection · T1190 · 9 related

Changelog

v5
  1. v5
    Candidate ingested via manual entry.2026-07-31
  2. v4
    Candidate ingested via manual entry.2026-07-31
  3. v3
    Candidate ingested via manual entry.2026-07-31
  4. v2
    Candidate ingested via manual entry.2026-07-31
  5. v1
    No changelog recorded for this version.2026-07-30

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