Detection rules › Sigma

macOS Gatekeeper User Override

Status
experimental
Severity
high
Log source
product macos, service endpointsecurity
Author
Eric Brown - Nebulock, Inc.
Source
github.com/Nebulock-Inc/macos-coresigma

Detects Gatekeeper user override events where users explicitly allow execution of unsigned or unnotarized applications. While sometimes legitimate, this can indicate social engineering attacks or user attempts to bypass security controls. Available on macOS 15+.

MITRE ATT&CK coverage

Rule body yaml

title: macOS Gatekeeper User Override
id: a1b2c3d4-e5f6-4a7b-8c9d-0e1f2a3b4c5d
status: experimental
description: 'Detects Gatekeeper user override events where users explicitly allow
  execution

  of unsigned or unnotarized applications. While sometimes legitimate, this can

  indicate social engineering attacks or user attempts to bypass security controls.

  Available on macOS 15+.

  '
author: Eric Brown - Nebulock, Inc.
date: 2025/10/31
modified: 2025/10/31
references:
- https://attack.mitre.org/techniques/T1553/001/
- https://attack.mitre.org/techniques/T1204/
logsource:
  product: macos
  service: endpointsecurity
detection:
  selection:
    esf.event_type: 146
    event.action: gatekeeper_user_override
  condition: selection
falsepositives:
- Users intentionally running trusted unsigned software
- Development and testing activities
- Legacy applications without notarization
fields:
- event_type
- event_name
- User
- file_path
- application
tags:
- attack.defense_evasion
- attack.t1553.001
- attack.execution
- attack.t1204
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
  esf.event_type: 146
  event.action: gatekeeper_user_override

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
esf.event_typeeq
  • 146
event.actioneq
  • gatekeeper_user_override