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I have just reversed a crackme in OllyDbg, and I was wondering if I can modify its code with application written in VB.NET. For example, to change JNZ (on specified address) for JMP.

EDIT:

I see there is a misconception. I was talking about creating patcher in Visual Basic.NET(programmatically change EXE code) to patch already reversed application. I know about Write/ReadProcessMemory that allows me to inject code after application execution(in that case it's loader not patcher), but how to overwrite EXE permanently?

blondkarol
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    Logically (I mean... if you have a basic computer software understanding), you cannot modify a running application directly (not within acceptable complexity levels). You can get the given source code, modify it (, compile this code if required) and then execute the (modified version of the) application again. In any case, this post is completely off-topic because of being a generic question about (very) basic ideas. – varocarbas Oct 11 '15 at 13:34

2 Answers2

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Changing JNZ to JMP is kind of bypassing some kind of verification inside application (serial number of if it is purchased or not, so if you have the source code, you can just comment which lines you don't want your application to execute

Xin Lok
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Patching a compiled program is possible with certain tools, you can even do that in runtime with code injection. But, as i understand from your question, you're talking about a vb .NET application and not a regular VB application. VB .NET applications compiles to bytecode (MSIL code) and not binary like regular VB applications, which makes it even more easier to reverse, you can actually "decompile" the .exe file to it's source code with a tool like ILSPY (see google), patch it, and then re-compiled it.

root
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