Sigma rule: Modifying Crontab

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-b0365844a5b5, updated 2022-04-16T00:00:00.000Z.

Rule

Title
Modifying Crontab
Status
test
Level
medium
Author
Pawel Mazur
Date
2022-04-16
File
rules/linux/builtin/cron/lnx_cron_crontab_file_modification.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects suspicious modification of crontab file.

Log source

product
linux
service
cron

Detection

keywords:
    - 'REPLACE'
condition: keywords

False positives (as the rule lists them)

  • Legitimate modification of crontab

Tags

  • attack.privilege-escalation
  • attack.execution
  • attack.persistence
  • attack.t1053.003

MITRE ATT&CK ids this rule names

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/linux/builtin/cron/lnx_cron_crontab_file_modification.yml

Sources and licences

  • SigmaHQ

    "Modifying Crontab" by Pawel Mazur (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/linux/builtin/cron/lnx_cron_crontab_file_modification.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Modifying Crontab",
entity page, dataset version ref-b0365844a5b5, updated 2022-04-16T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/af202fd3-7bff-4212-a25a-fb34606cfcbe (accessed 2026-11-03).
Underlying source: SigmaHQ rule af202fd3-7bff-4212-a25a-fb34606cfcbe, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.