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I have to reverse-engineer a VB P-CODE mode program. I had the program's P-CODE, but I don't know what it means. For example:

Proc: 421840
421100: 04 FLdRfVar                local_0098
421103: 04 FLdRfVar                local_0094
421106: 05 ImpAdLdRf:              435aec
421109: 24 NewIfNullPr             408868
42110C: 0d VCallHresult            CVBApplication::get_

I have to find the tools to reverse a program.I want to know what the P-CODE means.Thanks

  • 1
    google first hit says p-code means packed-code en.wikipedia.org/wiki/Microsoft_P-Code supposed to be executed by a visual basic virtual machine (msvbvmXXX.dll abandoned after vb6 in favour of clr and .net and a hunch search yields several decompiers for that code like p32dasm , vb-decompiler etc – blabb Apr 22 '15 at 8:15
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Here are the two best free and available resources about Microsoft's VB P-Code. First one, the list of opcodes (here). Second one, a 12 pages document written by Alex Ionescu on how to decompile and analyze VB binaries (here).

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VB Decompiler Pro decompiles VB P-Code to Visual Basic code. See below for an example of the decompilation output:

Decompilation

Alternatively, if you're looking for help in analyzing the raw P-Code itself, you can check out the following links in addition to the links that yaspr posted:

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In addition to the Alex Ionescu paper, there's also a useful 27-page paper, VISUAL BASIC REVERSED - A decompiling approach by Andrea Geddon.

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