In which file are system and user account passwords stored?

`/etc/passwd` stores user account information like username, UID, GID, home directory, and shell, but typically contains an 'x' in the password field, indicating that the actual password hash is in `/etc/shadow`.

`/etc/login.defs` defines system-wide password policies, such as minimum password length and age, but does not store individual user passwords.

The `/etc/shadow` file stores encrypted password hashes, expiration information, and other security-related details for user accounts. This file is only readable by the root user, ensuring the confidentiality of password hashes and protecting against unauthorized access.

`/etc/secure` is not a standard Linux file for storing user passwords; it might refer to system security configurations in some contexts but not direct password storage.