mirror of
https://github.com/DosX-dev/Astral-PE
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DosX
77 lines
3.4 KiB
C#
77 lines
3.4 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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using System.Text;
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namespace AstralPE.Obfuscator.Modules {
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public class UpxPackerMutator : IAstralPeModule {
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/// <summary>
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/// Detects and removes the UPX version signature from the PE file and changes the imports hash.
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/// </summary>
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/// <param name="raw">The raw byte array of the PE file.</param>
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/// <param name="pe">The parsed PE 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 IMAGE_OPTIONAL_HEADER.</param>
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/// <param name="sectionTableOffset">Offset to section table start.</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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if (pe.ImageSectionHeaders == null)
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throw new InvalidPeImageException();
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// Check for any section named "UPX"
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if (!pe.ImageSectionHeaders.Any(s => s.Name?.Contains("UPX") == true))
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return;
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// Signature pattern: 4 bytes for version + null + "UPX!"
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// e.g., "4.25\0UPX!" = 4 + 1 + 4 = 9 bytes
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for (int i = 0; i < raw.Length - 8; i++) {
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if (raw[i + 4] == 0x00 &&
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raw[i + 5] == 'U' && raw[i + 6] == 'P' &&
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raw[i + 7] == 'X' && raw[i + 8] == '!') {
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// Clear 9-byte UPX signature
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Patcher.ReplaceBytes(raw, raw.Skip(i).Take(9).ToArray(), new byte[9]);
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break;
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}
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}
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if (pe.IsExe) {
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// Change imports hash. Yes, we sacrifice ExitProcess, but it works
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byte[] exit = Encoding.ASCII.GetBytes('\0' + "ExitProcess" + '\0'),
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fake = Encoding.ASCII.GetBytes('\0' + "CopyContext" + '\0');
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Patcher.ReplaceBytes(raw, exit, fake);
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}
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}
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}
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}
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