Linux Setuid Capability Set on a Binary via Setcap Utility — Sigma Rule

Rule metadata and linked tags

Author: Luc Génaux. Source status: experimental; severity: low. Source dates: 2026-01-24 / not supplied.

{
  "product": "linux",
  "category": "process_creation"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: b79a8ce2abdcc3acc053218ab0e83a3a226a90da599a33a143e8e5246a5747a0

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Linux Setuid Capability Set on a Binary via Setcap Utility
id: ed447910-bc30-4575-a598-3a2e49516a7a
status: experimental
description: |
    Detects the use of the 'setcap' utility to set the 'setuid' capability (cap_setuid) on a binary file.
    This capability allows a non privileged process to make arbitrary manipulations of user IDs (UIDs), including setting its current UID to a value that would otherwise be restricted (i.e. UID 0, the root user).
    This behavior can be used by adversaries to backdoor a binary in order to escalate privileges again in the future if needed.
references:
    - https://man7.org/linux/man-pages/man8/setcap.8.html
    - https://dfir.ch/posts/linux_capabilities/
    - https://juggernaut-sec.com/capabilities/#cap_setuid
author: Luc Génaux
date: 2026-01-24
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1548
    - attack.t1554
logsource:
    product: linux
    category: process_creation
detection:
    selection:
        Image|endswith: '/setcap'
        CommandLine|contains: 'cap_setuid'
    condition: selection
falsepositives:
    - Unknown
level: low

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://man7.org/linux/man-pages/man8/setcap.8.html
• https://dfir.ch/posts/linux_capabilities/
• https://juggernaut-sec.com/capabilities/#cap_setuid