/etc/passwd and /etc/shadow
Where this stands
One published detection covers this technique. Every one is unverified — no rule on Siemphony has been executed against real telemetry.
What the technique is
Adversaries may attempt to dump the contents of /etc/passwd and /etc/shadow to enable offline password cracking. Most modern Linux operating systems use a combination of /etc/passwd and /etc/shadow to store user account information, including password hashes in /etc/shadow. By default, /etc/shadow is only readable by the root user. Linux stores user information such as user ID, group ID, home directory path, and login shell in /etc/passwd. A "user" on the system may belong to a person or a service. All password hashes are stored in /etc/shadow - including entries for users with no passwords and users with locked or disabled accounts. Adversaries may attempt to read or dump the /etc/passwd and /etc/shadow files on Linux systems via command line utilities such as the cat command. Additionally, 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 - for example, via the command /usr/bin/unshadow /etc/passwd /etc/shadow > /tmp/crack.password.db. Since the user information stored in /etc/passwd are linked to the password hashes in /etc/shadow, an adversary would need to have access to both.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN1234
Adversaries attempt to read sensitive files such as /etc/passwd and /etc/shadow for credential dumping. This may involve access to the files directly via command-line utilities (e.g., cat, less), creation of backup copies, or parsing through post-exploitation frameworks. Multi-event correlation includes elevated process execution, file access/read on sensitive paths, and anomalous read behaviors tied to non-root or unusual users.
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