Summary

Netsparker identified a misconfigured sandbox attribute in an iframe.

Impact

IFrame sandboxing enables a set of extra restrictions for the content in the inline frame.

Same Origin policy allows one window to access properties/functions of another one only if they come from the same protocol, the same port and the same domain.
           
URLs from the same origin:
            
http://site.com
http://site.com/
http://site.com/my/page.html
        
URLs not from the same origin:
            
http://www.site.com  (sub domain)
http://site.org      (different domain)
https://site.com     (different protocol)
http://site.com:8080 (different port)
    

When the sandbox attribute is set, the iframe content is treated as being from a unique origin, forms and scripts are disabled, links are prevented from targeting other browsing contexts and plugins are disabled.

When misconfigured sandbox attribute of an iframe on the same origin:

  • Compromised website in the iframe might affect the users in parent web application.
  • With a sandbox attribute containing both the allow-same-origin and allow-scripts flags, framed page can reach up into the parent and remove the sandbox attribute entirely.
Remediation
  • Avoid the usage of allow-same-origin and allow-scripts at the same time.