Potential Privilege Escalation via OverlayFS

edit

Identifies an attempt to exploit a local privilege escalation (CVE-2023-2640 and CVE-2023-32629) via a flaw in Ubuntu’s modifications to OverlayFS. These flaws allow the creation of specialized executables, which, upon execution, grant the ability to escalate privileges to root on the affected machine.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*

Severity: high

Risk score: 73

Runs every: 5m

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

Maximum alerts per execution: 100

References:

Tags:

  • Domain: Endpoint
  • OS: Linux
  • Use Case: Threat Detection
  • Tactic: Privilege Escalation
  • Use Case: Vulnerability
  • Data Source: Elastic Defend

Version: 4

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

edit
sequence by process.parent.entity_id, host.id with maxspan=5s
  [process where host.os.type == "linux" and event.action == "exec" and event.type == "start" and
    process.name == "unshare" and process.args : ("-r", "-rm", "m") and process.args : "*cap_setuid*"  and user.id != "0"]
  [process where host.os.type == "linux" and event.action == "uid_change" and event.type == "change" and
    user.id == "0"]

Framework: MITRE ATT&CKTM