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Detection rules › Sigma

Suspicious MacOS Firmware Activity

Status
test
Severity
medium
Log source
category process_creation, product macos
Author
Austin Songer @austinsonger
Source
github.com/SigmaHQ/sigma

Detects when a user manipulates with Firmward Password on MacOS. NOTE - this command has been disabled on silicon-based apple computers.

Known false positives

  • Legitimate administration activities

MITRE ATT&CK coverage

TacticTechniques
ImpactNo specific technique

Telemetry coverage

PlatformRecord / event type
macOSESF event exec (NOTIFY): Fires after execve(2) or posix_spawn(2) succeeds, delivering a post-fact record of the new process.

Rule body

title: Suspicious MacOS Firmware Activity
id: 7ed2c9f7-c59d-4c82-a7e2-f859aa676099
status: test
description: Detects when a user manipulates with Firmward Password on MacOS. NOTE - this command has been disabled on silicon-based apple computers.
references:
    - https://github.com/usnistgov/macos_security/blob/932a51f3e819dd3e02ebfcf3ef433cfffafbe28b/rules/os/os_firmware_password_require.yaml
    - https://www.manpagez.com/man/8/firmwarepasswd/
    - https://support.apple.com/guide/security/firmware-password-protection-sec28382c9ca/web
author: Austin Songer @austinsonger
date: 2021-09-30
modified: 2022-10-09
tags:
    - attack.impact
logsource:
    category: process_creation
    product: macos
detection:
    selection1:
        Image: '/usr/sbin/firmwarepasswd'
        CommandLine|contains:
            - 'setpasswd'
            - 'full'
            - 'delete'
            - 'check'
    condition: selection1
falsepositives:
    - Legitimate administration activities
level: medium

Stages and Predicates

Stage 0: condition

selection1

Stage 1: selection1

selection1:
    Image: '/usr/sbin/firmwarepasswd'
    CommandLine|contains:
        - 'setpasswd'
        - 'full'
        - 'delete'
        - 'check'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • check
  • delete
  • full
  • setpasswd
field:"CommandLine" kind:match
Imageeq
  • /usr/sbin/firmwarepasswd
field:"Image" kind:eq value:"/usr/sbin/firmwarepasswd"