Potential Container Escape via Modified notify_on_release Fileedit
This rule detects modification of the cgroup notify_on_release file from inside a container. When the notify_on_release flag is enabled (1) in a cgroup, then whenever the last task in the cgroup exits or attaches to another cgroup, the command specified in the release_agent file is run and invoked from the host. A privileged container with SYS_ADMIN capabilities, enables a threat actor to mount a cgroup directory and modify the notify_on_release flag in order to take advantage of this feature, which could be used for further privilege escalation and container escapes to the host machine.
Rule type: eql
Rule indices:
- logs-cloud_defend*
Severity: high
Risk score: 73
Runs every: 5m
Searches indices from: now-6m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References:
Tags:
- Data Source: Elastic Defend for Containers
- Domain: Container
- OS: Linux
- Use Case: Threat Detection
- Tactic: Privilege Escalation
Version: 1
Rule authors:
- Elastic
Rule license: Elastic License v2
Rule queryedit
file where event.module == "cloud_defend" and event.action == "open" and event.type == "change" and file.name : "notify_on_release"
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Privilege Escalation
- ID: TA0004
- Reference URL: https://attack.mitre.org/tactics/TA0004/
-
Technique:
- Name: Escape to Host
- ID: T1611
- Reference URL: https://attack.mitre.org/techniques/T1611/