Software Engineering Institute

ZyXEL Wireless N300 NetUSB Router NBG-419N running firmware version 1.00(BFQ.6)C0, and possibly earlier versions, has been reported to contain multiple vulnerabilities.

CWE-425: Direct Request - CVE-2014-0353
Authentication for content located in any subdirectory of the web root may be bypassed by escaping the "/" characters in the URL. For example, curl -v "http://<deviceip>/local%2Fadvance%2Fwlan.asp"

CWE-259: Use of Hard-coded Password - CVE-2014-0354
A hard-coded password of qweasdzxc may be used to login to the index.asp page.

CWE-121: Stack-based Buffer Overflow - CVE-2014-0355
The checkWeather function is vulnerable to a buffer overflow when parsing the forecastrss xml file provided from hxxp://weather.yahooapis.com/forecastrss. The vulnerability may be triggered with the following XML content: <yweather:condition  text="Partly Cloudy"  code="47"  temp="<overflow data goes here>". An attacker would need a man-in-the middle vantage point to exploit this vulnerability and the user would need to access index.asp in a web browser to trigger the download.

The detectWeather function is vulnerable to a buffer overflow of the WeatherCity and WeatherDegree variables.

The UpnpAddRunRLQoS(), UpnpDeleteRunRLQoS(), and UpnpDeletePortCheckType() functions are reported to be vulnerable to a buffer overflow vulnerability.

The udps command SET COUNTRY is reported to be vulnerable to command injection and a buffer overflow.

CWE-78: Improper Neutralization of Special Elements used in an OS Command - CVE-2014-0356
The detectWeather(), set_language(), SystemCommand(), and NTPSyncWithHost() functions in management.c are reported to be vulnerable to command injection.

The udps commands SET COUNTRY, SET WLAN SSID, SET WLAN CHANNEL, SET WLAN STATUS, SET WLAN COUNTRY are reported to be vulnerable to command injection. The udps process is only accessible from the LAN side.

The CVSS score below was calculated for CVE-2014-0356.

A remote unauthenticated attacker on the local area network may be able to inject arbitrary commands or run arbitrary code.

We are currently unaware of a practical solution to this problem. Please consider the following workarounds.

Restrict Access
As a general good security practice, only allow connections from trusted hosts and networks. Do not enable remote management of the device on the WAN interface.