CODEWITHSUNDEEP
c++executablecompiled
Dan
Dan

Reputation: 341

Modify dll function call in compiled exe

I have an exe file that I had written a while back and cannot find the source code for it (it was written in C++).

It calls the MessageBoxA function in user32.dll and passes necessary parameters to it. I want to modify the flags parameter to include the MB_ICONERROR (0x10) flag.

How do I go about finding which bytes in the exe file need to be modified to accomplish this?

Upvotes: 0

Views: 2077

Answers (1)

Luiz Felipe
Luiz Felipe

Reputation: 1189

You need a disassembler like ICE or IDA. https://www.hex-rays.com/products/ida/support/download.shtml. Load the executable. Find the Win32 API call on Names Window, to find it, just type the function name. Then double click CODE XREF to go to referenced caller.

enter image description here

Then you get what you want: enter image description here

Just select the line and click on Hex-View to get the address.

enter image description here

Upvotes: 2

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