In the Macally WIFISD2-2A82 Media and Travel Router 2.000.010, the Guest user is able to reset its own password. This process has a vulnerability which can be used to take over the administrator account and results in shell access. As the admin user may read the /etc/shadow file, the password hashes of each user (including root) can be dumped. The root hash can be cracked easily which results in a complete system compromise.
CWE-287 - Improper Authentication
Improper (or broken) authentication attacks are widespread, and have accounted for many of the worst data breaches in recent years. Improper authentication attacks are a class of vulnerabilities where an attacker impersonates a legitimate user by exploiting weaknesses in either session management or credential management to gain access to the user’s account. This can result in disclosure of sensitive information, and can lead to system compromise, theft, identity theft, and fraud.