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Re: [WEB SECURITY] Universal XSS with PDF files: highly dangerous



RSnake wrote:
2. While thinking more about this solution, I observed that if the attacker can have an "agent" sharing the same IP address with the victim (by agent I mean an entity that can communicate with the target web site and read back its response data), then the algorithms I suggested will not be effective. Note that an attacker can share IP address with the victim when both share a forward proxy (e.g. some universities and ISPs), or when the attacker and victim share the same machine (multi-user environment). Still, that narrows down the attack surface significantly.

It should be noted that this isn't as rare as just a few universities
and ISPs.  This also happens in lots of corporate networks (rogue user
on the internal network),  it happens with lots of internet cafe's, it
happens with AOL (~5MM users) and it happens with TOR users.  So while,
yes, I agree it is better than nothing it is hardly a rock solid
solution for anyone on a shared IP.

The point is - someone with shared IP is vulnerable ONLY to an attacker with the same IP. Which makes attacks much less generic and much more painful. Rock solid it ain't, but I think it's a pretty good band-aid until all (hmmm...) clients upgrade to Acrobat Reader 8.0.

-Amit