Vulnerability Development: Re: unpacking UPX or PE-packed binaries

[Gadi Evron <ge () linuxbox org>]

Blue Boar wrote:
> Karma wrote:
>
> > Just interested in how AV R&D companies unpack worms with complex UPX 
> > and PE
> > pack protocols.
>
> The modified UPX packing is a pretty small change usually.  Compare one 
> with a standard UPX header for the same version.  There are a variety of 
> unpackers out there.
[Hey BB, 'sup? :)]

Having taken a look at the samples, they are indeed agobots (look a bit 
more like phatbots, but who can tell anymore?), but polymorphic ones 
(polybots).
Also, they are packed using PE-Crypt.Wonk, which would explain why upx 
-d didn't work.
        Gadi Evron.