Re: [Full-disclosure] Downloads Folder: A Binary Planting Minefield

[Sanguinarious Rose <SanguineRose@xxxxxxxxxxxxxxxxx>]

On Mon, Feb 20, 2012 at 2:28 PM, Jeffrey Walton <noloader@xxxxxxxxx> wrote:
> Hi Mitja,
>
> On Fri, Feb 17, 2012 at 11:32 AM, ACROS Security Lists <lists@xxxxxxxx> wrote:
>>
>> This blog post reveals a bit of our research and provides an advance 
>> notification of
>> a largely unknown remote exploit technique on Windows. More importantly, it 
>> provides
>> instructions for protecting your computers from this technique while waiting 
>> for the
>> affected software to correct its behavior.
>>
>> http://blog.acrossecurity.com/2012/02/downloads-folder-binary-planting.html
>
> $ Look for the presence of any *.dll files in the Downloads
> $ folder and do the same as in the previous step.
> $ Delete all files from the Downloads folder.
> I don't believe a PE/PE+ executable needs a DLL extension to be loaded
> by LoadLibrary and friends.
>

They do not need a specific extension for LoadLibrary() to work.

This is more having to do with dll search paths which has been a known
exploit vector for a long while now. I do know Win7 fixes this by just
not checking the local directories when it loads a .exe, I am unsure
if Vista does the same, and I am positive WinXP checks local
directories first since I've done so under WinXP.

They might have something interesting with the msiexec.exe with it
checking the local directory first. I would call this a programming
issue by the installer not specifying a full path and no validations.

If a dev was really concerned when they called LoadLibrary() they
could just use SetDllDirectory(), GetDllDirectory(), and friends to
manipulate where they look for dlls.

Since I responded to something in this subject, I would like to share
my personal opinion this doesn't really seem like a major exploit
vector. It appears to fall to usual do and do not of basic security.
Obviously downloading files from a suspect website is a security risk.

> Perhaps a scanning/cleansing tool would be helpful.
>
> Jeff
>
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Charter: http://lists.grok.org.uk/full-disclosure-charter.html
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