Suspicious Passwd File Event Actionedit
Monitors for the generation of a passwd password entry via openssl, followed by a file write activity on the "/etc/passwd" file. The "/etc/passwd" file in Linux stores user account information, including usernames, user IDs, group IDs, home directories, and default shell paths. Attackers may exploit a misconfiguration in the "/etc/passwd" file permissions or other privileges to add a new entry to the "/etc/passwd" file with root permissions, and leverage this new user account to login as root.
Rule type: eql
Rule indices:
- logs-endpoint.events.*
- logs-auditd_manager.auditd-*
Severity: medium
Risk score: 47
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: Privilege Escalation
- Data Source: Elastic Defend
Version: 1
Rule authors:
- Elastic
Rule license: Elastic License v2
Rule queryedit
sequence by host.id, process.parent.pid with maxspan=1m [process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and process.name == "openssl" and process.args == "passwd" and user.id != "0"] [file where event.dataset == "auditd_manager.auditd" and host.os.type == "linux" and file.path == "/etc/passwd" and process.parent.pid != 1 and not auditd.data.a2 == "80000" and event.outcome == "success" and user.id != "0"]
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/