VBA and P-code, (Mon, Sep 26th)

I want to draw your attention to some great work Dr. Bontchev did.

pcodedmp.py is a VBA P-code disassembler. Microsoft Office documents contain VBA macros in several forms. They contain the source code, but also compiled P-code. Dr. Bontchev created a proof-of-concept document that executes P-code and does not contain the corresponding source code. Here is the output from his pcodedmp.py tool for his PoC document:

python pcodedmp.py -d poc2b.docProcessing file: poc2b.doc===============================================================================Module streams:Macros/VBA/ThisDocument - 1949 bytesLine #0:        FuncDefn (Sub / Property Set) func_00000078Line #1:        LitStr 0x001D This could have been a virus!        Ld vbInformation        Ld vbOKOnly        Add        LitStr 0x0006 Virus!        ArgsCall MsgBox 0x0003Line #2:        LitStr 0x0008 calc.exe        Paren        ArgsCall Shell 0x0001Line #3:        EndSub

Dr. Bontchev also coded a plugin for oledump.

Didier Stevens
Microsoft MVP Consumer Security
blog.DidierStevens.com DidierStevensLabs.com

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