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Corkami PE Testing - Known Failure Fixes #151

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ekilmer opened this issue Mar 16, 2021 · 0 comments
Open
2 tasks

Corkami PE Testing - Known Failure Fixes #151

ekilmer opened this issue Mar 16, 2021 · 0 comments

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@ekilmer
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ekilmer commented Mar 16, 2021

Within #145, there are very simple tests to detect whether pe-parse would correctly identify the executables as PE, without erroring. Unfortunately (but not unexpectedly), there are a few executables that are not parsed correctly.

Ideally, we should at least test and enforce that we support parsing of any PE in the Corkami dataset.

  • There are no test exceptions (read: known failures) when processing the Corkami dataset of PEs

Reference to known failing tests:

static const std::unordered_set<std::string> kKnownPEFailure{
"virtsectblXP.exe", "maxsec_lowaligW7.exe",
"maxsecXP.exe", "nullSOH-XP.exe",
"tinyXP.exe", "tinydllXP.dll",
"virtrelocXP.exe", "foldedhdrW7.exe",
"maxvals.exe", "d_nonnull.dll",
"reloccrypt.exe", "d_resource.dll",
"fakerelocs.exe", "lfanew_relocW7.exe",
"bigSoRD.exe", "tinyW7.exe",
"reloccryptW8.exe", "standard.exe",
"exe2pe.exe", "tinygui.exe",
"dllfwloop.dll", "tinydrivXP.sys",
"tiny.exe", "tinydll.dll",
"foldedhdr.exe", "dllmaxvals.dll",
"reloccryptXP.exe", "dosZMXP.exe",
"tinyW7_3264.exe", "dllfw.dll",
"hdrcode.exe", "ibrelocW7.exe",
"d_tiny.dll", "sc.exe"};

Secondly, a much bigger task would be to confirm that pe-parse is correctly parsing all and only the information that the Corkami PEs claim to exhibit.

  • There are specific PE field tests/asserts for the Corkami PEs to ensure correctness

How to Start Investigating

First, run git submodule update --init to pull the Corkami dataset (We will be focusing on the PEs here https://github.com/corkami/pocs/tree/master/PE/bin).

Then, running the standalone dump-pe tool that is included in this repo should be an easy way to iterate on code changes, since the testing logic is basically the same.

$ ./build/dump-pe/dump-pe tests/assets/corkami-poc-dataset/PE/bin/virtsectblXP.exe
Error: 3 (Invalid section)
Location: ParsePEFromBuffer:2394

Use that information as a starting point for where to begin debugging. Moreover, most, if not all, of the PEs have a corresponding asm file that provides the source code for building the PE and how the file is constructed. Use this information to gain a better understanding of why pe-parse is having difficulty parsing it and what kind of fix would be needed. Here it is for our example https://github.com/corkami/pocs/blob/master/PE/virtsectblXP.asm

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