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Index > Windows > Debugger needed to change jz to jnz

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sylwek32



Joined: 27 Apr 2006
Posts: 339
sylwek32
Hello,
i tryed to modify jz to jnz in w32dasm and ida but it doesnt work.
Is there an other debugger for that task??

Please help
Post 11 Nov 2006, 18:50
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LocoDelAssembly
Your code has a bug


Joined: 06 May 2005
Posts: 4633
Location: Argentina
LocoDelAssembly
ollydbg?
Post 11 Nov 2006, 19:00
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okasvi



Joined: 18 Aug 2005
Posts: 382
Location: Finland
okasvi
in case you dont know how to do it in OllyDbg, after changing the jz to jnz, look for 'save changes to executable' from right-click menu
Post 11 Nov 2006, 19:11
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Ehtyar



Joined: 26 Sep 2006
Posts: 51
Ehtyar
Make sure you're using the correct opcode. You will end up with an invalid image if you use an opcode of different length. There are a few utilities around, but i use this one for the most part currently. Hope it helps.

Ehtyar.


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Post 11 Nov 2006, 20:38
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sylwek32



Joined: 27 Apr 2006
Posts: 339
sylwek32
thanks!
Post 11 Nov 2006, 23:12
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okasvi



Joined: 18 Aug 2005
Posts: 382
Location: Finland
okasvi
usually, OllyDbg's built-in utility to 'code' while debugging works so no need for manually changing opcodes.
Post 11 Nov 2006, 23:42
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OzzY



Joined: 19 Sep 2003
Posts: 1029
Location: Everywhere
OzzY
You gave me a idea to write a generic file patcher to patch files based on the offset got in w32dasm.
Soon I'll upload in my home page when it's completed.
For screenshot see: http://board.flatassembler.net/topic.php?t=6179
If you want an alpha version send me a PM.
Post 12 Nov 2006, 02:40
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vid
Verbosity in development


Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia
vid
note: to negate condition of jump, you just need to invert lowest bit. eg 70<->71, 72<->73 etc.

to make it unconditional jump, rewrite it to EB

common thingies when you... err.. "reversere engineer" a lot Wink
Post 12 Nov 2006, 11:18
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Maverick



Joined: 07 Aug 2006
Posts: 251
Location: Citizen of the Universe
Maverick
vid: you've been reported to the proper authorities ;D
Post 12 Nov 2006, 12:01
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