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2016-002: Stored XSS in Google Sites

2016-002: Stored XSS in Google Sites

Original release date: February 16, 2016
Last revised: February 16, 2016
Discovered by: Fabián Cuchietti
Severity: 6.1/10 (CVSSv3 Base Metrics)


Google Sites is a structured wiki and Web page-creation tool offered by Google as part of the Google Apps for Work productivity suite. The goal of Google Sites is for anyone to be able to create a team-oriented site where multiple people can collaborate and share files.


It possible to bypass the restriction on JavaScript execution in Google with article by embedding an <iframe> with a data and base64. The persistent (or stored) XSS vulnerability is a more devastating variant of a cross-site scripting flaw: it occurs when the data provided by the attacker is saved by the server, and then permanently displayed on &quot;normal&quot; pages returned to other users in the course of regular browsing, without proper HTML escaping. The affected resource is when you create/Edit a new article. </iframe>



First XSS:
1) Go to:
2) Create > Blank template > Site Name: > Create
3) Browse to the URL vulnerable: (example)
4) Edit > HTML > here insert the following payload: "><iframe src="data:text/html;base64,PHNjcmlwdD5hbGVydCgnWFNTJyk8L3NjcmlwdD4"></iframe>
5) To update
6) PoC:

Second XSS:
1) Browse to URL vulnerable: (example)
2) Create Page
3) Assign a name to your site: > Select a template: File cabinet > Create
4) Add file > select our file * .swf > Copy the link to "See"
5) PoC:


An attacker can execute arbitrary HTML or script code in a targeted user&#39;s browser. This can leverage to steal sensitive information as google email, user credentials, personal data, etc.



This vulnerability have been corrected.


February 16, 2016: Initial release.


  • December 13, 2015 Vulnerability acquired by Internet Security Auditors
  • December 13, 2015 Contact with Google Security Team
  • December 14, 2015 Vendor Response/Feedback
  • February 16, 2016 Advisory published.


The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Internet Security Auditors accepts no responsibility for any damage caused by the use or misuse of this information.


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