File Permission Modification in Writable Directoryedit

Identifies file permission modifications in common writable directories by a non-root user. Adversaries often drop files or payloads into a writable directory, and change permissions prior to execution.

Rule type: query

Rule indices:

  • auditbeat-*

Severity: low

Risk score: 21

Runs every: 5 minutes

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum signals per execution: 100

Tags:

  • Elastic
  • Linux

Version: 1

Added (Elastic Stack release): 7.8.0

Potential false positivesedit

Certain programs or applications may modify files or change ownership in writable directories. These can be exempted by username.

Rule queryedit

event.action:executed and process.name:(chmod or chown or chattr or
chgrp) and process.working_directory:(/tmp or /var/tmp or /dev/shm)
and not user.name:root

Threat mappingedit

Framework: MITRE ATT&CKTM