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

[RSnake <rsnake@xxxxxxxxxxxx>]

> 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.

-RSnake
http://ha.ckers.org/
http://sla.ckers.org/
http://ha.ckers.org/fierce/