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

[Henrik Bøgh <henrik.list () boegh net>]

On Friday 23 April 2004 04:25 Karma wrote to 
"Undisclosed-Recipient:;"@securityfocus.com:

[...]

> Been trying to disect the recent Gaobot variants and getting no where with
> my generic UPX-unpacker. Since this is more and more commonly used, I
> thought I would be wise to consult the Lists.
In the case of at least one of the Gaobot's the UPX-header was (probably 
deliberately by the author) mangled after the binary was packed. This method 
"obfuscating" code has been seen before. If you could restore the original 
UPX-header unpacking the code should be trivial.

> Karma
-- 
Venlig hilsen / Kind regards
Henrik Bøgh ( henrik.list () boegh net )
  "Hva' glor du på? Det' sgu'da bare en hammer mand!"
   -- Søren Pilmark som Grethe i 'Ørkenens sønner'