Software Engineering Institute

CWE-255: Credentials Management - CVE-2015-5994

Medialink MWN-WAPR300N by default uses the common admin:admin credentials for the web management interface and uses medialink:password for the wireless network. An attacker within range of a wireless network using default settings can connect and gain privileged access to the web management interface. Additionally, default credentials can be leveraged in remote attacks such as cross-site request forgery.

CWE-784: Reliance on Cookies without Validation and Integrity Checking in a Security Decision - CVE-2015-5995

Authorization in the Medialink MWN-WAPR300N is handled by checking the HTTP Cookie header that is sent by the client. An unauthenticated, local area network (LAN) attacker can modify the cookie header of a request to "Cookie: language-en; admin:language-en" and gain admin access to restricted pages of the web management interface without any knowledge of credentials. This authentication bypass works regardless of whether the administrator account username has been changed from 'admin.'

A nearly identical vulnerability has been reported in the Tenda N3 Wireless N150 Home Router. This likely indicates a supply chain relationship between some Mediabridge and Tenda components.

CWE-352: Cross-Site Request Forgery (CSRF) - CVE-2015-5996

Medialink MWN-WAPR300N routers contain a global cross-site request forgery (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 does not require a victim to be logged in.

The CVSS score below describes CVE-2015-5996.

Additional issues affecting these routers have been disclosed by researcher David Spector.

A remote, unauthenticated attacker may be able to induce an authenticated user into making an unintentional request to the web server that will be treated as an authentic request. A LAN-based attacker can bypass authentication to take complete control of a vulnerable device.

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. While passwords do not provide any additional security against LAN-based attackers due to the authentication bypass vulnerability, 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.