RE: First vulnerabilities in the SP2 - XP ?...

["Thor Larholm" <tlarholm () pivx com>]

> From: Radoslav Dejanović [mailto:radoslav.dejanovic () opsus hr] 
> > On Monday 16 August 2004 15:58, Jrme ATHIAS wrote:
> > http://www.heise.de/security/artikel/50051

> This might be SP2 bug only if the same bug can't be repeated 
> on pre-SP2 machine. Didn't test, but I think this is an old 
> trick. Anyone care to test it?

The entire concept of the Zone.Identifier altenate data stream is new to XPSP2. Whenever you download any file from the 
web IE will add an ADS called Zone.Identifier which specifies what IE security zone the file originated from. Later, 
when the user tries to execute this file, Explorer itself will check for this ADS. If it does not exist Explorer will 
simply execute the file as it has always done, but if it does exist and it specifies the Internet zone Explorer will 
then check for a valid digital signature. If such a signature is not found Explorer will prompt the user and ask 
whether to execute this unknown executable from an unknown publisher.

Regardless of whether we think this has a high practical impact the advisory from Jürgen does specify a way to 
circumvent a desired security functionality which has been addded to XPSP2. Circumventing a desired security 
functionality is always interested, especially seeing as this is one of many first steps in a move toward digitally 
signing all executables on the Windows platform.



Regards

Thor Larholm
Senior Security Researcher
PivX Solutions
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