IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
Potential Privilege Escalation via CVE-2023-4911edit
This rule detects potential privilege escalation attempts through Looney Tunables (CVE-2023-4911). Looney Tunables is a buffer overflow vulnerability in GNU C Library’s dynamic loader’s processing of the GLIBC_TUNABLES environment variable.
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: 1
Rule authors:
- Elastic
Rule license: Elastic License v2
Investigation guideedit
## Setup Elastic Defend integration does not collect environment variable logging by default. In order to capture this behavior, this rule requires a specific configuration option set within the advanced settings of the Elastic Defend integration. To set up environment variable capture for an Elastic Agent policy: - Go to Security → Manage → Policies. - Select an Elastic Agent policy. - Click Show advanced settings. - Scroll down or search for linux.advanced.capture_env_vars. - Enter the names of env vars you want to capture, separated by commas. - For this rule the linux.advanced.capture_env_vars variable should be set to "GLIBC_TUNABLES". - Click Save. After saving the integration change, the Elastic Agents running this policy will be updated and the rule will function properly. For more information on capturing environment variables refer - https://www.elastic.co/guide/en/security/current/environment-variable-capture.html
Rule queryedit
sequence by host.id, process.parent.entity_id, process.executable with maxspan=5s [process where host.os.type == "linux" and event.action == "exec" and event.type == "start" and process.env_vars : "*GLIBC_TUNABLES=glibc.*=glibc.*=*"] with runs=5
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Privilege Escalation
- ID: TA0004
- Reference URL: https://attack.mitre.org/tactics/TA0004/
-
Technique:
- Name: Exploitation for Privilege Escalation
- ID: T1068
- Reference URL: https://attack.mitre.org/techniques/T1068/