Software Engineering Institute

CWE-255: Credentials Management - CVE-2015-7283

The ZyXEL NBG-418N web administration interface uses non-random default credentials of admin:1234. A local area network attacker can gain privileged access to a vulnerable device's web management interfaces or leverage default credentials in remote attacks such as cross-site request forgery.

CWE-352: Cross-Site Request Forgery (CSRF) - CVE-2015-7284

The ZyXEL NBG-418N contains a global CSRF vulnerability. An attacker can perform actions with the same permissions as a victim user, provided the victim has an active session and is induced to trigger the malicious request. Note that in combination with default credentials, an attacker can establish an active session as part of an attack and therefore would not require a victim to be logged in.

The CVSS score below reflects CVE-2015-7282.

A remote, unauthenticated attacker may be able to execute arbitrary script in the context of the end-user's browser session or perform actions as an authenticated user. A local area network attacker can take complete control of a device using default admin credentials.

The CERT/CC is currently unaware of a practical solution to this problem. Until these vulnerabilities are addressed, users should consider the following workarounds.

Restrict access and use strong passwords

As a general good security practice, only allow trusted hosts to connect to the LAN. Implement strong passwords for WiFi and for the web management interface. Strong passwords can help to prevent blind guessing attempts that would establish sessions for CSRF attacks. LAN hosts should not browse the Internet while the web management interface has an active session in a browser tab.