Bugtraq mailing list archives
A technique to mitigate cookie-stealing XSS attacks
From: "Michael Howard" <mikehow () microsoft com>
Date: Tue, 5 Nov 2002 10:44:24 -0800
During the Windows Security Push in Feb/Mar 2002, the Microsoft Internet Explorer team devised a method to reduce the risk of cookie-stealing attacks via XSS vulnerabilities. In a nutshell, if Internet Explorer 6.0 SP1 detects a cookie that has a trailing HttpOnly (case insensitive) it will return an empty string to the browser when accessed from script, such as by using document.cookie. Obviously, the server must add this option to all outgoing cookies. Note, this does _not fix_ XSS bugs in server code; it only helps reduce the potential damage from cookie disclosure threats. Nothing more. Think of it as a very small insurance policy! A full write-up outlining the HttpOnly flag, as well as source code to set this option, is at http://msdn.microsoft.com/library/en-us/dncode/html/secure10102002.asp. Cheers, Michael Howard Secure Windows Initiative Microsoft Corp. Writing Secure Code http://www.microsoft.com/mspress/books/5612.asp
Current thread:
- A technique to mitigate cookie-stealing XSS attacks Michael Howard (Nov 05)
- Re: A technique to mitigate cookie-stealing XSS attacks Florian Weimer (Nov 05)
- Re: A technique to mitigate cookie-stealing XSS attacks Valdis . Kletnieks (Nov 07)
- Re: A technique to mitigate cookie-stealing XSS attacks Florian Weimer (Nov 08)
- Re: A technique to mitigate cookie-stealing XSS attacks David Wagner (Nov 08)
- Re: A technique to mitigate cookie-stealing XSS attacks Valdis . Kletnieks (Nov 07)
- Re: A technique to mitigate cookie-stealing XSS attacks Justin King (Nov 09)
- Re: A technique to mitigate cookie-stealing XSS attacks Ulf Harnhammar (Nov 11)
- RE: A technique to mitigate cookie-stealing XSS attacks jasonk (Nov 12)
- Re: A technique to mitigate cookie-stealing XSS attacks Seth Arnold (Nov 14)
- Re: A technique to mitigate cookie-stealing XSS attacks Ulf Harnhammar (Nov 11)
- <Possible follow-ups>
- Re: A technique to mitigate cookie-stealing XSS attacks Matthew Collins (Nov 07)
- Re: A technique to mitigate cookie-stealing XSS attacks Nick Simicich (Nov 08)
(Thread continues...)
- Re: A technique to mitigate cookie-stealing XSS attacks Florian Weimer (Nov 05)