Didier Stevens

Thursday 15 July 2010

The Hex Factor RE Challenge

Filed under: My Software — Didier Stevens @ 18:11

Last year for Brucon, I produced some reverse engineering challenges (and I’m producing new ones for this year’s edition).

The Hex Factor blog posted the solution for level 300.

The source code for the challenge can be downloaded here. It’s completely written in assembler, even the I/O routines.

Here’s a trick I used to create your own EXE from assembler code, without any library:

A simple assembly program:

    BITS 32

    ret

Assemble with nasm: nasm -f win32 ret.asm -o ret.o

And link with mingw32‘s linker: ld -s ret.o -o ret.exe

Result:

1 Comment »

  1. Nice Breakpoint trick.

    I am too one of the guys that like to write thousands of lines in assemblers. just makes fun.

    Comment by Tom — Saturday 2 October 2010 @ 22:26


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