Applied Cybernetics Group
T1003.008 — /etc/passwd and /etc/shadow
coverage gap
- Technique
T1003.008- Tactics
- Credential Access
- MISP citations
- 0
- KEV CVEs mapped
- 1
- Community rules
- 0
- thrunt rules
- 0
- Upstream
- https://attack.mitre.org/techniques/T1003/008
MITRE description
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) Linux stores user information such as user ID, group ID, home directory path, and login shell in <code>/etc/passwd</code>. A "user" on the system may belong to a person or a service. All password hashes are stored in <code>/etc/shadow</code> - including entries for users with no passwords and users with locked or disabled accounts.(Citation: Linux Password and Shadow File Formats) Adversaries may attempt to read or dump the <code>/etc/passwd</code> and <code>/etc/shadow</code> files on Linux systems via command line utilities such as the <code>cat</code> command.(Citation: Arctic Wolf) Additionally, the Linux utility <code>unshadow</code> can be used to combine the two files in a format suited for password cracking utilities such as John the Ripper - for example, via the command <code>/usr/bin/unshadow /etc/passwd /etc/shadow > /tmp/crack.password.db</code>(Citation: nixCraft - John the Ripper). Since the user information stored in <code>/etc/passwd</code> are linked to the password hashes in <code>/etc/shadow</code>, an adversary would need to have access to both.
KEV CVEs mapped to this technique
Per MITRE CTID's hand-curated KEV→ATT&CK mappings — these are the actively-exploited vulnerabilities behind this technique's KEV signal.
Detection coverage
No detection coverage exists for this technique — no SigmaHQ community rule carries its tag and thrunt has not authored one yet. Techniques on this list are exactly where hand-authoring effort goes next; see the rollup for the full queue.