Under certain circumstances the Linux users credentials may be recovered by an authenticated user.
The storage of passwords in a recoverable format makes them subject to password reuse attacks by malicious users. In fact, it should be noted that recoverable encrypted passwords provide no significant benefit over plaintext passwords since they are subject not only to reuse by malicious attackers but also by malicious insiders. If a system administrator can recover a password directly, or use a brute force search on the available information, the administrator can use the password on other accounts.