huntrule

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
AnalysisDetection

ATT&CK techniques

Execution

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. 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

Related detections9 linkedT1059 — drag to rearrange
Malicious Web Server Process Spawning Command Interpreter via Web Shell (via process_creation)
Suspicious VMware Guest Operation Output Staging in vmware-system Temp Directory (via file_event)
Malicious Command Shell Spawned by SQL Server via Process Creation (via process_creation)
Suspicious Script Interpreter Spawned by Excel via DarkGate Lure
Suspicious AutoHotkey Script Execution from User Writable Path by DarkGate
Malicious China Chopper Web Shell Command Pattern in IIS Worker Process (via process_creation)
Malicious AutoHotKey Runner AutoNotify Executing AHKBot Looper Script (via process_creation)
Malicious IIS Worker Process Spawning Command Shell after ASP.NET ViewState Injection (via process_creation)
Suspicious MSSQL xp_cmdshell Enablement via sp_configure (via process_creation)
Linux auditd: BPFDoor .pid or .lock file access in /var/run
Pivot detection · T1059 · 9 related

Changelog

v3
  1. v3
    Candidate ingested via manual entry.2026-07-31
  2. v2
    Candidate ingested via manual entry.2026-07-31
  3. 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.