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Leveraging Windows' Built In Disassembler

Posted by adeyblue, 25 April 2012 · 1,290 views

windows
Wait, there's a disassembler built into Windows? Well, only in the sense that a supermarket that has the ingredients to build a cake. There's no ready made pastry hidden away in the depths of system32, unlike there is for file hashing [1].

What there is though, is an aisle full of ingredients going by the name of DbgEng.dll. This fellow forms part of the debugging tools triumverate with its more illustrious counterpart dbghelp.dll and the mysterious symsrv.dll. DbgEng contains the interfaces which make up WinDbg's core functionality, a portion of such is disassembling. So, being the sort of chef who would appear on a Gordon Ramsay show in quite short order, I rustled up a quick messily coded bun.

It's not IDA or Hiew, it's not meant to be. But for an 'objdump -d' like, quick and dirty tool that handles the 3 most common Windows architectures (as well as ARM and Alpha!) and doesn't require a toolchain to be installed, it's perfectly acceptable for my uses. It may be for others too, so have at it if you should so desire.

Download it here

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AMD64 output with symbols.

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ARM output from files compiled by eMbedded VC.

The code was to be part of a larger project which never was and so, is in a terrible state mixed with this library and that. In scant consolation, below are the basic steps to how it works, and how you can do it yourself if you're suitably deranged. The help for these interfaces and functions is on MSDN (obviously) and also the debugger.chm help file that comes with the Debugging Tools For Windows package which also houses the up to date headers, libs, and other helpful little programs.

Pseudocode steps


[1] - The lesser known tool is certutil.exe, the command line to hash files is
certutil -hashfile <file> <hash name>
Hash name can be SHA1, SHA256, SHA384, SHA512, MD2, MD4, MD5, must be uppercase




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