Detection rules › Sigma

Unsigned Kernel Extension Load Attempt

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

Detects attempts to load unsigned kernel extensions which may indicate rootkit installation or malicious kernel-level access

MITRE ATT&CK coverage

Rule body yaml

title: Unsigned Kernel Extension Load Attempt
id: 7e7a1a47-45dd-4f97-8205-1d6aea67f682
status: experimental
description: Detects attempts to load unsigned kernel extensions which may indicate
  rootkit installation or malicious kernel-level access
references:
- https://attack.mitre.org/techniques/T1547/006/
- https://objective-see.com/blog/blog_0x4B.html
author: Eric Brown - Nebulock, Inc.
date: 2025/10/29
tags:
- attack.persistence
- attack.privilege_escalation
- attack.t1547.006
logsource:
  product: macos
  service: endpointsecurity
  category: kernel_extension
detection:
  selection:
    esf.event_type: 17
    event.action: kextload
  filter_signed:
    TeamID: '*'
  condition: selection and not filter_signed
falsepositives:
- Legitimate unsigned kexts in development environments
- Testing scenarios
level: critical
modified: 2025/01/15

Stages and Predicates

Stage 0: condition

selection and not filter_signed

Stage 1: selection

selection:
  esf.event_type: 17
  event.action: kextload

Stage 2: not filter_signed

filter_signed:
  TeamID: '*'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
TeamIDwildcard*

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
  • 17
event.actioneq
  • kextload