Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking. Most modern Linux operating systems use a combination of <code>/etc/passwd</code> and <code>/etc/shadow</code> to store user account information including password hashes in <code>/etc/shadow</code>. By default, <code>/etc/shadow</code> is only readable by the root user.(Citation: Linux Password and Shadow File Formats)
The Linux utility, unshadow, can be used to combine the two files in a format suited for password cracking utilities such as John the Ripper:(Citation: nixCraft - John the Ripper) <code># /usr/bin/unshadow /etc/passwd /etc/shadow > /tmp/crack.password.db</code>
View in MITRE ATT&CK®| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| linux_auditd_alerts_and_log_analytics_agent_integration | Linux auditd alerts and Log Analytics agent integration | technique_scores | T1003.008 | /etc/passwd and /etc/shadow |
Comments
This control may alert on suspicious access to encrypted user passwords. The documentation does not reference "/etc/passwd" and "/etc/shadow" directly nor does it describe the logic in determining suspicious access.
References
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