Potential Privilege Escalation via UID INT_MAX Bug Detected

calendar Sep 5, 2023 · Domain: Endpoint OS: Linux Use Case: Threat Detection Tactic: Privilege Escalation Data Source: Elastic Defend  ·
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This rule monitors for the execution of the systemd-run command by a user with a UID that is larger than the maximum allowed UID size (INT_MAX). Some older Linux versions were affected by a bug which allows user accounts with a UID greater than INT_MAX to escalate privileges by spawning a shell through systemd-run.

Elastic rule (View on GitHub)

 1[metadata]
 2creation_date = "2023/07/27"
 3integration = ["endpoint"]
 4maturity = "production"
 5min_stack_comments = "New fields added: required_fields, related_integrations, setup"
 6min_stack_version = "8.3.0"
 7updated_date = "2023/07/27"
 8
 9[rule]
10author = ["Elastic"]
11description = """
12This rule monitors for the execution of the systemd-run command by a user with a UID that is larger than the maximum 
13allowed UID size (INT_MAX). Some older Linux versions were affected by a bug which allows user accounts with a UID 
14greater than INT_MAX to escalate privileges by spawning a shell through systemd-run. 
15"""
16from = "now-9m"
17index = ["logs-endpoint.events.*"]
18language = "eql"
19license = "Elastic License v2"
20name = "Potential Privilege Escalation via UID INT_MAX Bug Detected"
21references = [
22    "https://twitter.com/paragonsec/status/1071152249529884674", 
23    "https://github.com/mirchr/security-research/blob/master/vulnerabilities/CVE-2018-19788.sh",
24    "https://gitlab.freedesktop.org/polkit/polkit/-/issues/74"]
25risk_score = 47
26rule_id = "d55436a8-719c-445f-92c4-c113ff2f9ba5"
27severity = "medium"
28tags = ["Domain: Endpoint", "OS: Linux", "Use Case: Threat Detection", "Tactic: Privilege Escalation", "Data Source: Elastic Defend"]
29timestamp_override = "event.ingested"
30type = "eql"
31query = '''
32process where host.os.type == "linux" and event.action == "exec" and event.type == "start" and 
33process.name == "systemd-run" and process.args == "-t" and process.args_count >= 3 and user.id >= "1000000000"
34'''
35
36[[rule.threat]]
37framework = "MITRE ATT&CK"
38
39[[rule.threat.technique]]
40id = "T1068"
41name = "Exploitation for Privilege Escalation"
42reference = "https://attack.mitre.org/techniques/T1068/"
43
44[rule.threat.tactic]
45id = "TA0004"
46name = "Privilege Escalation"
47reference = "https://attack.mitre.org/tactics/TA0004/"

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