File Permission Modification in Writable Directory

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File Permission Modification in Writable Directory

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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: eql

Rule indices:

  • auditbeat-*
  • logs-endpoint.events.*

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

  • Domain: Endpoint
  • OS: Linux
  • Use Case: Threat Detection
  • Tactic: Defense Evasion

Version: 104

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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process where host.os.type == "linux" and event.type == "start"and
  process.name in ("chmod", "chown", "chattr", "chgrp") and
  process.working_directory in ("/tmp", "/var/tmp", "/dev/shm") and
  not process.parent.name in ("update-motd-updates-available") and
  not user.name == "root"

Framework: MITRE ATT&CKTM