mirror of
https://github.com/DosX-dev/Astral-PE
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DosX
64 lines
3.0 KiB
C#
64 lines
3.0 KiB
C#
/*
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* This file is part of the Astral-PE project.
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* Copyright (c) 2025 DosX. All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* Astral-PE is a low-level post-compilation PE header mutator (obfuscator) for native
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* Windows x86/x64 binaries. It modifies structural metadata while preserving execution integrity.
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*
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* For source code, updates, and documentation, visit:
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* https://github.com/DosX-dev/Astral-PE
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*/
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using PeNet;
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namespace AstralPE.Obfuscator.Modules {
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public class ChecksumWiper : IAstralPeModule {
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/// <summary>
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/// Overwrites the 4-byte CheckSum field (offset +0x40) in the optional header with zero, if it is non-zero.
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/// </summary>
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/// <param name="raw">The raw byte buffer of the PE file.</param>
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/// <param name="pe">The parsed PE file structure.</param>
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/// <param name="e_lfanew">Offset to IMAGE_NT_HEADERS.</param>
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/// <param name="optStart">Offset to Optional Header.</param>
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/// <param name="sectionTableOffset">Offset to section headers.</param>
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/// <param name="rnd">Random instance (unused).</param>
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public void Apply(ref byte[] raw, PeFile pe, int e_lfanew, int optStart, int sectionTableOffset, Random rnd) {
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// Sanity check to ensure header structures are available
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if (pe.ImageNtHeaders == null || pe.ImageSectionHeaders == null)
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throw new InvalidPeImageException();
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// Calculate offset to CheckSum field (offset +0x40 in optional header)
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int checksumOffset = optStart + 0x40;
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// Bounds check
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if (checksumOffset + 4 > raw.Length)
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throw new ArgumentOutOfRangeException(nameof(raw), "Checksum offset exceeds buffer length.");
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// If checksum is already zero, skip
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if (pe.ImageNtHeaders.OptionalHeader.CheckSum == 0)
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return;
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// Clear the 4-byte CheckSum field
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BitConverter.GetBytes(0u).CopyTo(raw, checksumOffset);
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}
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}
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} |