huntrule

macOS: Time Machine Exclusion Added via tmutil addexclusion

Alerts on tmutil commands that add new Time Machine exclusions to skip backing up selected files.

FreeReviewedSigma · Medium · v2
Product
macos
Category
process_creation
Author
Pratinav Chandra (SigmaHQ), DRL 1.1
Published
2024-05-29
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Impact

  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 process executions of tmutil on macOS where a Time Machine exclusion is being added using the addexclusion argument. Attackers may use this to prevent specific files or paths from being included in backups, reducing the likelihood of recovery and forensic visibility. Detection relies on process creation telemetry, matching the tmutil binary and the presence of the addexclusion command-line string.

Reporting behind it

Related detections9 linkedT1490 — drag to rearrange
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Malicious Volume Shadow Copy Deletion via vssadmin
Suspicious Free Space Wipe via cipher.exe
Malicious Shadow Copy Deletion Via WMI
Volume Shadow Copy Deletion via vssadmin or wmic
Malicious Inhibit System Recovery via Backup and Shadow Copy Deletion (via process_creation)
Malicious Shadow Copy Deletion via vssadmin
macOS: Time Machine Exclusion Added via tmutil addexclusion
Pivot detection · T1490 · 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.