Re: 0-day PDF exploit

[Justin Klein Keane <jukeane () sas upenn edu>]

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Adobe has a work around (but doesn't seem to have a fix yet) for this
vulnerability (which they categorize as "critical").  They also state
(and testing seems to validate) that impact is limited to Windows XP
machines with IE 7.

http://www.adobe.com/support/security/advisories/apsa07-04.html


Justin C. Klein Keane

Sr. Programmer Analyst and Information Security Specialist
University of Pennsylvania
School of Arts and Sciences Computing
3600 Market St.
Philadelphia, PA 19104

eric () rachner us wrote:
> > Why everybody said it is a zero day about PDF? it's just a fault in
> > IE7, or just want to make a big media hit? real PDF zero day will
> > exists in the PDF's file format, or some Adobe's expanded functions.
>
> Actually, it's about PDF *and* IE7.  Both are at fault, and if either  
> one of them was doing the right thing, the exploit would fail.
>
> The first fault is Adobe's.  Because it's their code that first  
> acquires the input from the attacker, it's their job IMHO to validate  
> it properly, but they don't.  Instead, they turn around and tell  
> Windows to open the bogus URI.
>
> The second fault is IE7's.  The protocol handler used to fail  
> gracefully by rejecting this kind of malformed URI, but now it  
> doesn't.  The new behavior is to turn around and call ShellExecute()  
> with data taken from the URI.
>
> I prefer to think of it this way: Adobe's code has been doing the  
> wrong thing for years, and they've gotten lucky.  But now, a new bug  
> in IE7 has come along which makes the old bug in Adobe's code  
> exploitable.
>
> - Eric
>
>
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