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CERT Coordination Center

ZyXEL NBG-418N router uses default credentials and is vulnerable to cross-site request forgery

Vulnerability Note VU#330000

Original Release Date: 2015-12-10 | Last Revised: 2015-12-10


ZyXEL NBG-418N router, firmware version 1.00(AADZ.3)C0, uses default credentials and is vulnerable to cross-site request forgery.


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.

Vendor Information


ZyXEL Affected

Notified:  October 08, 2015 Updated: December 10, 2015



Vendor Statement

We have not received a statement from the vendor.

Vendor Information

We are not aware of further vendor information regarding this vulnerability.

CVSS Metrics

Group Score Vector
Base 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P
Temporal 6.5 E:F/RL:U/RC:C
Environmental 1.6 CDP:ND/TD:L/CR:ND/IR:ND/AR:ND



These vulnerabilities were reported by Joel Land of the CERT/CC.

This document was written by Joel Land.

Other Information

CVE IDs: CVE-2015-7283, CVE-2015-7284
Date Public: 2015-12-10
Date First Published: 2015-12-10
Date Last Updated: 2015-12-10 15:06 UTC
Document Revision: 7

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