Monday, June 30, 2008

XSS Comedy at McAfee Secure's Expense

In celebration of the deadline for PCI Requirement 6.6 compliance as of June 30, 2008, I thought I'd share a little web app sec comedy at McAfee Secure's expense.
As well you should know by know, the existence of XSS vulnerabilities in a site that is required to meet PCI DSS standards means that the site IS NOT PCI COMPLIANT. Very simple, right?
Let's consider the McAfee Secure/Hacker Safe-branded site for Organize-It.
A seemingly handy site, perfect for your HGTV types, likely with healthy credit card limits. Uh-oh, here it comes. Oh yes, Organize-It handles credit cards and is thus beholden to PCI DSS.
Organize-It is also proudly displaying a current McAfee Secure badge, indicating that it's tested daily.
Given the focus of many a recent discussion it shouldn't shock you that Organize-It is vulnerable to XSS.
What's funny is what Organize-It does with regard to "handling" malformed requests.
Where a typical test string for XSS might be " script payload /script (characters removed or Blogger will let me XSS myself), you won't get much use from such a string via either direct form submittal or URL encoding. But when the site barfed up '; // LEAVE THIS VALUE var sli_cId = 90;, while under investigation, my ruh-roh meter went off.
I decided to play with my trusty marquee test and found interesting results. The actual search form field is limited to 41 characters (er?). So my complete string of " marquee message /marquee didn't fit for direct submittal BUT THE MARQUEE RENDERED ANYWAY! Basically, half the test string worked: " marquee h1 This_site_is_NOT_McAfee_S
Forget the marquee tag on the blacklist, did we?
But here's the real icing on the cake. The uber-intuitive search index reinterpreted my message with what I can only imagine are index keywords. Thus "This site is NOT McAfee Secure" scrolls across the Organize-It site as "this sit is not coffee secure".
OMG! My daily quad shot Americano has been pwn3d to the core!
Here's the URL if you don't believe me, or the video if you prefer.
Forget PCI compliance, bring on the Gong Show hook, Chuck!
Cheers.

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