huntrule

Linux Command Lines Creating Symlink to /etc/passwd

Alerts on Linux command lines attempting to create symlinks to /etc/passwd via ln -s/ln -f patterns.

FreeReviewedSigma · High · v3
Product
linux
Author
Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2019-04-05
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 matches Linux process command lines containing patterns for creating a symbolic link to /etc/passwd using ln with -s and optionally -f. Attackers use symlinks to redirect file operations and potentially manipulate how privileged processes read sensitive files. The detection relies on command-line text telemetry that captures the executed ln arguments.

Reporting behind it

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Linux Command Lines Creating Symlink to /etc/passwd
Pivot detection · T1204.001 · 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.