Linux auditd: BPFDoor .pid or .lock file access in /var/run

Alerts on auditd-monitored access to specific /var/run .pid and .lock files associated with BPFDoor-style behavior.

FreeReviewedSigma · High · v3

Product: linux
Service: auditd
Author: Rafal Piasecki (SigmaHQ), DRL 1.1
Published: 2022-08-10
Updated: 2026-07-31

ATT&CK techniques

Execution

Recon
Resource Dev
Initial Access
Execution
- T1059Command and Scripting Interpreter
- T1106Native API
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags access to specific BPFDoor-related PID and lock files under /var/run. Attackers may create or modify these files to persist, coordinate, or masquerade as legitimate system activity. It relies on Linux auditd telemetry reporting PATH events for the listed .pid and .lock files.

Reporting behind it

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Linux auditd: BPFDoor .pid or .lock file access in /var/run

Pivot detection · T1059 · 9 related

Changelog

v3
Candidate ingested via manual entry.2026-07-31
v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

linux-auditd-rule-for-bpfdoor-related-pid-and-lock-file-access-under-var-run-808146b2

title: "Linux auditd: BPFDoor .pid or .lock file access in /var/run"
id: 18519e6c-0122-42b8-9ef5-18f9dec53647
status: test
description: This rule flags access to specific BPFDoor-related PID and lock files under /var/run. Attackers may create or modify these files to persist, coordinate, or masquerade as legitimate system activity. It relies on Linux auditd telemetry reporting PATH events for the listed .pid and .lock files.
references:
  - https://www.sandflysecurity.com/blog/bpfdoor-an-evasive-linux-backdoor-technical-analysis/
  - https://www.elastic.co/security-labs/a-peek-behind-the-bpfdoor
  - https://www.rapid7.com/blog/post/tr-bpfdoor-telecom-networks-sleeper-cells-threat-research-report/
  - https://github.com/rapid7/Rapid7-Labs/blob/741c7196ec12a0a56b63463d1fd726ff14d3a97a/BPFDoor/rapid7_detect_bpfdoor.sh
  - https://github.com/SigmaHQ/sigma/blob/master/rules/linux/auditd/path/lnx_auditd_bpfdoor_file_accessed.yml
author: Rafal Piasecki, Huntrule Team
date: 2022-08-10
modified: 2026-03-30
tags:
  - attack.execution
  - attack.t1106
  - attack.t1059
logsource:
  product: linux
  service: auditd
detection:
  selection:
    type: PATH
    name:
      - /var/run/aepmonend.pid
      - /var/run/auditd.lock
      - /var/run/cma.lock
      - /var/run/console-kit.pid
      - /var/run/consolekit.pid
      - /var/run/daemon.pid
      - /var/run/hald-addon.pid
      - /var/run/hald-smartd.pid
      - /var/run/haldrund.pid
      - /var/run/hp-health.pid
      - /var/run/hpasmlit.lock
      - /var/run/hpasmlited.pid
      - /var/run/kdevrund.pid
      - /var/run/lldpad.lock
      - /var/run/mcelog.pid
      - /var/run/system.pid
      - /var/run/uvp-srv.pid
      - /var/run/vmtoolagt.pid
      - /var/run/xinetd.lock
  condition: selection
falsepositives:
  - Unlikely
level: high
license: DRL-1.1
related:
  - id: 808146b2-9332-4d78-9416-d7e47012d83d
    type: derived

Convert

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