Multiple StarCraft - Basic Reversing with OLLYDBG

[LCSBSSRHXXX]

For this tutorial you will need StarCraft and the debugger OLLYDBG.
What we are going to acomplish in this tutorial is write a patched executable that will allow us to run multiple instances of StarCraft. This will teach you some basic reverse engineering skills and some basic functions of OLLYDBG.

Run OLLYDBG and go to the file menu and select Open.


Find StarCraft.exe in your StarCraft directory


Once you open StarCraft OLLYDBG will look like this


Right click -> Search for -> All refrenced text strings


A new window will open up, go to your window setting and tile your windows vertically so they look like this.


While looking though the list of all the refrenced text strings you will eventually run across this string saying "StarCraft Check For Other Instances"


Double Click that item and it will bring you to the line where that is used.


Select the four lines in the brackets and NOP them.


The lines will look like this after they are NOPed


Now right click the changes we made -> Copy to exicuatble -> Selection


A new window will come up, right click the selected changes in there -> Save to file.


Save your new patched version as Multiple StarCraft.exe


Run StarCraft.exe and Multiple StarCraft.exe


Success!

[DarthSlyGuy]

LLGW!

[p00onu]

Very nice LCS.

[LCSBSSRHXXX]

Bump! I re-uploaded all of the images and fixed my first post because when the attachments broke a while back it pretty much made this tutorial useless, so today I decided to fix this up so it can be used. I hope someone actually uses this tutorial and learns something from it, shout out in here if you have any problems, questions, comments, feedback on the tutorial, but I think it is pretty straight forward. (I made it step by step so anyone can do it and learn about OLLYDBG / basic reversing / asm with out having to think too much)

[LCSTest]

Test.

[Maid]

well, I've tried to do this tutorial over and over again. but still shows no result. I've tried to start the to .exe separatly and at the same time. what have I done wrong? Oo