Fix shellcode emulation: use memory-mapped image for decoy PEs#284
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Fix shellcode emulation: use memory-mapped image for decoy PEs#284williballenthin wants to merge 4 commits intomasterfrom
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Co-authored-by: Moritz <mr-tz@users.noreply.github.com>
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The ApiModuleLoader was writing raw PE file bytes into emulated memory, but PE sections have different file offsets vs virtual addresses. Shellcode that walks the PEB InInitializationOrderModuleList to find kernel32 and then parses its export directory would read garbage because the .edata section data was at its file offset rather than its virtual address. Use pefile's get_memory_mapped_image() so sections are placed at their correct virtual addresses, matching how Windows loads DLLs. Also fixes Process.ldr_entries being a shared class-level mutable default instead of a per-instance list, and corrects the test config module order to list ntdll before kernel32 (matching the default config). Closes #45
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williballenthin
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Mar 10, 2026
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| jit = JitPeFile(self._arch, base=self._base) | ||
| img_data = jit.get_decoy_pe_image(self._name, all_exports) | ||
| jit.get_decoy_pe_image(self._name, all_exports) |
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now this doesn't return anything that we use? that seems like the API is designed wrong, then.
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are we using it for a side effect (in which case the name shouldn't be get_*)? or is this now dead code?
williballenthin
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Mar 10, 2026
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remove this file, too contrived.
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Summary
ApiModuleLoaderwrote raw PE file bytes into emulated memory, but PE sections have different file offsets vs virtual addresses. Shellcode walking the PEBInInitializationOrderModuleListto find kernel32 and parse its export directory would read garbage data because.edatawas at its file offset rather than its virtual address.pefile.get_memory_mapped_image()so sections are placed at their correct virtual addresses, matching how Windows actually loads DLLs.Process.ldr_entrieswas a shared class-level mutable list (classic Python gotcha) instead of per-instance, causing cross-test contamination. Moved to__init__.test.jsonnow lists ntdll before kernel32, matching the default config order.Test plan
test_peb_shellcode.pywith two tests:WinExecfrom kernel32 viaInInitializationOrderModuleList_ordered_peb_modules())Closes #45
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