Detection rules › Sigma

macOS UL Unusual TCC Access Request

Status
experimental
Severity
medium
Log source
category tcc, product macos, service unifiedlog
Author
Eric Brown - Nebulock, Inc.
Source
github.com/Nebulock-Inc/macos-coresigma

Detects unusual TCC (Transparency, Consent, and Control) access requests that may indicate malicious behavior

Known false positives

  • Legitimate installer applications
  • System configuration tools

MITRE ATT&CK coverage

TacticTechniques
CollectionNo specific technique

Telemetry coverage

Rule body

title: macOS UL Unusual TCC Access Request
id: c3d4e5f6-a7b8-9012-cdef-345678901234
status: experimental
description: Detects unusual TCC (Transparency, Consent, and Control) access requests that may indicate malicious behavior
author: Eric Brown - Nebulock, Inc.
date: 2025/01/15
modified: 2025/01/15
logsource:
    product: macos
    service: unifiedlog
    category: tcc
detection:
    selection:
        subsystem: com.apple.TCC
        message|contains:
            - 'Full Disk Access'
            - 'Camera'
            - 'Microphone'
            - 'Screen Recording'
        ProcessName|contains:
            - '.dmg'
            - '.pkg'
            - '/tmp'
            - '/var/tmp'
    condition: selection
falsepositives:
    - Legitimate installer applications
    - System configuration tools
level: medium
tags:
    - attack.collection

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    subsystem: com.apple.TCC
    message|contains:
        - 'Full Disk Access'
        - 'Camera'
        - 'Microphone'
        - 'Screen Recording'
    ProcessName|contains:
        - '.dmg'
        - '.pkg'
        - '/tmp'
        - '/var/tmp'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
ProcessNamematch
  • .dmg
  • .pkg
  • /tmp
  • /var/tmp
field:"process_name" kind:match
messagematch
  • Camera
  • Full Disk Access
  • Microphone
  • Screen Recording
field:"message" kind:match
subsystemeq
  • com.apple.TCC
field:"subsystem" kind:eq value:"com.apple.TCC"