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Scheduled tasks modification detected


The ScheduledTaskModification signature aims to identify when scheduled tasks or their configurations have been tampered with. Scheduled tasks are a common mechanism used on Linux-based systems to execute commands or scripts at predefined times or after specific intervals. However, adversaries might manipulate these tasks for malicious purposes, such as maintaining persistence after a reboot.


This signature focuses on the various aspects of task scheduling, specifically revolving around the crontab and its associated files and directories.

Monitoring alterations to these files and directories is critical because changes could be indicative of unauthorized activities. The signature also identifies when certain commands related to scheduling are executed, ensuring a broader coverage against potential threats.


This signature primarily aims to safeguard systems against unauthorized or malicious modifications to scheduled tasks. By detecting such changes, it alerts administrators or security systems, helping prevent potential breaches or maintaining a persistent presence by adversaries.


  • ID: TRC-1027
  • Version: 1
  • Name: Scheduled tasks modification detected
  • EventName: scheduled_task_mod
  • Description: Monitors for changes to task scheduling configurations or the execution of scheduling-related commands. Detecting such modifications is crucial because adversaries can use these tasks for persistence mechanisms.
  • Properties:
  • Severity: 2
  • Category: persistence
  • Technique: Cron
  • Kubernetes_Technique: N/A
  • id: attack-pattern--2acf44aa-542f-4366-b4eb-55ef5747759c
  • external_id: T1053.003


Upon detecting any of the predefined suspicious actions, the signature triggers a Finding structure, signaling potential threats. The findings don't contain specific data fields related to the event, except for the event's metadata.

Events Used

This signature primarily listens to three event types:

  1. security_file_open - Checks if a scheduling-related file was opened, specifically with write permissions.
  2. security_inode_rename - Monitors if any of the scheduling-related files or directories got renamed.
  3. sched_process_exec - Listens for the execution of specific commands related to task scheduling.

By monitoring these events, the signature offers a comprehensive safeguard against the unauthorized alteration of scheduled tasks.