New File Exclusion Added To Time Machine Via Tmutil - MacOS

Description

Detects the addition of a new file or path exclusion to MacOS Time Machine via the "tmutil" utility. An adversary could exclude a path from Time Machine backups to prevent certain files from being backed up.

Query · sigma

selection_img:
- Image|endswith: /tmutil
- CommandLine|contains: tmutil
selection_cmd:
  CommandLine|contains: addexclusion
condition: all of selection_*

Known false positives

  • Legitimate administrator activity
Raw source New File Exclusion Added To Time Machine Via Tmutil - MacOS · Sigma
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Published by SigmaHQ/sigma ↗, licensed under Detection Rule License 1.1 ↗. Reproduced here unmodified. 
title: New File Exclusion Added To Time Machine Via Tmutil - MacOS
id: 9acf45ed-3a26-4062-bf08-56857613eb52
status: test
description: |
    Detects the addition of a new file or path exclusion to MacOS Time Machine via the "tmutil" utility.
    An adversary could exclude a path from Time Machine backups to prevent certain files from being backed up.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1490/T1490.md#atomic-test-12---disable-time-machine
    - https://www.loobins.io/binaries/tmutil/
author: Pratinav Chandra
date: 2024-05-29
tags:
    - attack.impact
    - attack.t1490
logsource:
    category: process_creation
    product: macos
detection:
    selection_img:
        - Image|endswith: '/tmutil'
        - CommandLine|contains: 'tmutil'
    selection_cmd:
        CommandLine|contains: 'addexclusion'
    condition: all of selection_*
falsepositives:
    - Legitimate administrator activity
level: medium

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