SANS ISC: Stored XSS vulnerability on YouTube actively abused?

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SANS ISC InfoSec Forums

XSS vulnerabilities are often underestimated, but they can sometimes be extremely dangerous. It looks as if couple of hours ago attackers started exploiting what looks like a stored XSS vulnerability on YouTube.

I don't want to go into details on how to exploit it until YouTube fixes it, but it indeed looks pretty widespread already. So far, all exploits I've seen just enter some benign HTML and are more of comment spam, but as this appears to be a full-fledged vulnerability things could get out of control easily unless this is fixed.

What could an attacker do? Well, they could steal your YouTube cookies, which probably doesn't mean much to them, but they could also post various JavaScript code that will execute in your browser, in the context of YouTube. I've seen nasty XSS attacks that are used to fake whole login screens and we know how many people use same passwords for multiple accounts.

We'll keep you informed on the development of this.

--
Bojan
INFIGO IS