Multiple directory traversal vulnerabilities in pam_timestamp.c in the pam_timestamp module for Linux-PAM 1.1.8 allow local users to create aribitrary files or possibly bypass authentication via a .. in the PAM_RUSER value to the get_ruser function or PAM_TTY value to the check_tty funtion, which is used by the format_timestamp_name function.The pam_userdb module for Pam uses a case-insensitive method to compare hashed passwords, which makes it easier for attackers to guess the password via a brute force attack.