Suspicious Cron Reboot Persistence Pointing to Hidden User Directory on Linux

PremiumReviewedSigma · Medium · v1
Product
linux
Category
process_creation
Author
HuntRule
Published
2026-09-15
Updated
2026-09-15

ATT&CK techniques

Execution → Priv Esc
  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Defense Evasion

  7. Cred Access

  8. Discovery

  9. Lateral Movement

  10. Collection

  11. C2

  12. Exfiltration

  13. Impact

What it detects

This rule detects a crontab entry using the reboot schedule to launch a binary from a hidden path under a user local bin directory which the opportunistic Log4j campaign uses to persist its componist implant across system restarts.

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Suspicious Linux Crontab Reboot Persistence to Hidden Sys Cache Binary (via process_creation)
Suspicious Cron Persistence Installing a Downloader via Command Line
Suspicious Cron Persistence File Creation in System Cron Directories (via file_event)
Suspicious Cron Persistence via etc cron.d tsar (via file_event)
Suspicious Cron Job Executing Binary From var tmp via Process Creation
Suspicious Cron Job Persistence Creation on Linux (via process_creation)
Suspicious Cron Persistence File Created in System Cron Directories
Suspicious Cron Reboot Persistence Pointing to Hidden User Directory on Linux
Pivot detection · T1053.003 · 9 related

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