Analyzing Malicious Office Documents with OLEDUMP

Microsoft office documents are a common vehicle used by malware authors to deliver malware. These documents, used for malicious purposes, are commonly referred to as maldocs. While there has been a variety of ways in which they have been used, one of the more prevalent is through the use of macros. Macros are written in Visual Basic for Applications (VBA), which is well documented on the Microsoft Developer Network (MSDN). This API allows malware authors to hook into life-cycle events of a document, such as AutoOpen, AutoClose and AutoExit (MSDN) in order to achieve code execution with minimal interaction from…

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Locating DLL Name from the Process Environment Block (PEB)

I often encounter software, especially when performing malware analysis, that dynamically constructs it’s own import table. This can be done for a variety of reasons and in a variety of ways. In this article, we’ll explore one method I recently encountered. I typically become suspicious of this activity when I see the following assembly instructions: mov ebx, fs:[ 0x30 ] mov ebx, [ ebx + 0xC ] mov ebx, [ ebx + 0x14] mov esi, [ ebx + 0x28 ]

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