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
23 Corporate Plaza #280
Newport Beach, CA 92660
http://www.pivx.com
thor@pivx.com
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Phone: +1 (949) 231-8496
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