Affected Software/Device: Zyxel ZYWall 100 Vulnerability: Cross Site Scripting Risk: Low Description: The ZyWALL 100 is designed to act as a secure gateway via xDSL/Cable modems or broadband routers for small to medium size companies. The ZyWALL 100 features an ICSA certified firewall, IPSec VPN capability, MultiNAT, web pages content filtering and an embedded web configurator for easy configuration and management. ZyWALL web based management interface utilizes referer header for serving 404 Error pages. The vulnerability can be exploited by requesting a non-existing web page with a specially crafted referer header. As the application does not properly sanitize the data contained in the referer header, desired script code can be run on client browser. Sample Request: GET /blah.htm HTTP/1.1 Host: www.site.com Referer: blaaaa"><script>alert(12345)</script>aaaah.htm Deniz CEVIK www.intellectpro.com.tr