Full Disclosure mailing list archives

Re: DLL hijacking with Autorun on a USB drive


From: Christian Sciberras <uuf6429 () gmail com>
Date: Tue, 31 Aug 2010 23:38:38 +0200

Adding to Charles' this dll hijacking is even less than a non-issue
considering that the user has opened the "bad" file in the first
place.

I don't see it a matter of changing the cwd, but rather the user
shouldn't be running stuff which he doesn't know about.
It's the same analogy Charles mentioned all over again.

Dan: "The security model people keep presuming exists, doesn't."

Dan, there was no security model, and no one assumed there was.
Running dubious files, from anywhere, is always a security risk.

This is more of an anti-virus fix than changing CWD: the
anti-virus/ips/whatever knows that the dll-to-be-loaded is from an
external source, and it should wail out a warning.

I fully acknowledge a message telling me I'm about to run an
executable I've just downloaded, but simply refusing to run it
properly isn't something I, (or normal users, for the matter) would
want.




Finally, this "Application X is vulnerable to dll hijcak" needs to
stop, right now. This whole darn thing is stupid...most if not all
applications set the CWD to the target path for several reasons.
Microsoft Office suite, for instance, keep backup (archives, caches
and whatnot) files in the same folder the main file resides. Switching
between directories is surely not an option.



On Tue, Aug 31, 2010 at 11:20 PM, Charles Morris <cmorris () cs odu edu> wrote:
On Tue, Aug 31, 2010 at 5:15 PM, Dan Kaminsky <dan () doxpara com> wrote:


Again, the clicker can't differentiate word (the document) from word (the
executable).  The clicker also can't differentiate word (the document) from
word (the code equivalent script).

The security model people keep presuming exists, doesn't.

Even the situation whereby a dll is dropped into a directory of documents --
the closest to a real exploit path there is -- all those docs can be
repacked into executables.


What?

I can differentiate my coolProposal.doc from msword.exe just fine..

If your statement is that the windows defaults should be changed,
including the "hide extensions" default, then I wholeheartedly agree
as I detailed in my first post. It's the first thing I turn off.

Many people who think the same way have considered that a
vulnerability in windows for years, I wouldn't consider it part of
the "DLL Hijacking" fiasco.

Cheers,
Charles

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_______________________________________________
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