Suspicious Cron Persistence via etc cron.d tsar (via file_event)

ATT&CK techniques

Execution → Priv Esc

Recon
Resource Dev
Initial Access
Execution
- T1053.003Cron
Persistence
- T1053.003Cron
Priv Esc
- T1053.003Cron
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects creation of a tsar cron job under etc cron.d as observed in the BrokenSesame research for host persistence. Dropping a system cron file lets an attacker run code as root on a schedule after escaping a container. The specific filename in the system cron directory is a strong persistence indicator.

Reporting behind it

Related detections9 linkedT1053.003 — drag to rearrange

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Linux eBPF Backdoor File Persistence via cron.d and sudoers.d (ebpfbackdoor)

Suspicious Cron Persistence via etc cron.d tsar (via file_event)

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.

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