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Windows Security Event 5379: Opened Password-Protected ZIP from Outlook Attachment

Flags Windows events where a password-protected ZIP is opened from Outlook Temporary Internet Files.

FreeReviewedSigma · High · v2
Product
windows
Service
security
Author
Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-05-09
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Initial Access → 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 matches Windows Security auditing events (EventID 5379) where a password-protected ZIP archive is opened via the Shell ZIP folder. It targets cases involving attachments from Outlook, specifically paths under \Temporary Internet Files\Content.Outlook, which can indicate user delivery of encrypted archive contents. The detection relies on the TargetName field containing both the Shell ZIP filename marker and the Outlook temporary directory path, signaling ZIP access through email attachment handling.

Reporting behind it

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Suspicious PS1Bot PowerShell Payload Written to ProgramData (via file_event)
Malicious Non-Interactive Encoded PowerShell Stager (via process_creation)
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Windows Security Event 5379: Opened Password-Protected ZIP from Outlook Attachment
Pivot detection · T1027 · 9 related

Changelog

v2
  1. v2
    Candidate ingested via manual entry.2026-07-31
  2. 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.