146 lines
4.6 KiB
C#
146 lines
4.6 KiB
C#
/*
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Copyright (C) 2011 de4dot@gmail.com
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This file is part of de4dot.
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de4dot is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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de4dot is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with de4dot. If not, see <http://www.gnu.org/licenses/>.
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*/
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using System;
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using System.IO;
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using ICSharpCode.SharpZipLib.Zip.Compression;
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using de4dot.code.PE;
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namespace de4dot.code.deobfuscators.dotNET_Reactor {
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class NativeImageUnpacker {
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PeImage peImage;
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bool isNet1x;
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public NativeImageUnpacker(PeImage peImage) {
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this.peImage = peImage;
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}
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public byte[] unpack() {
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var resources = peImage.Resources;
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var dir = resources.getRoot();
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if ((dir = dir.getDirectory(10)) == null)
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return null;
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if ((dir = dir.getDirectory("__")) == null)
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return null;
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var dataEntry = dir.getData(0);
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if (dataEntry == null)
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return null;
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var encryptedData = peImage.readBytes(dataEntry.RVA, (int)dataEntry.Size);
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if (encryptedData.Length != dataEntry.Size)
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return null;
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var keyData = getKeyData();
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if (keyData == null)
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return null;
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var decrypter = new NativeFileDecrypter(keyData);
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decrypter.decrypt(encryptedData, 0, encryptedData.Length);
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byte[] inflatedData;
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if (isNet1x) {
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var buffer = new byte[0x1000];
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var memStream = new MemoryStream();
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var inflater = new Inflater();
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inflater.SetInput(encryptedData, 0, encryptedData.Length);
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while (true) {
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int count = inflater.Inflate(buffer, 0, buffer.Length);
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if (count == 0)
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break;
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memStream.Write(buffer, 0, count);
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}
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inflatedData = memStream.ToArray();
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}
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else {
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int inflatedSize = BitConverter.ToInt32(encryptedData, 0);
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inflatedData = new byte[inflatedSize];
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var inflater = new Inflater();
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inflater.SetInput(encryptedData, 4, encryptedData.Length - 4);
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int count = inflater.Inflate(inflatedData);
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if (count != inflatedSize)
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return null;
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}
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if (BitConverter.ToInt16(inflatedData, 0) != 0x5A4D)
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return null;
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return inflatedData;
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}
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static uint[] baseOffsets = new uint[] {
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0x1C00, // DNR 4.0 & 4.1
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0x1900, // DNR 4.2.7.5
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0x1B60, // DNR 4.2.8.4, 4.3 & 4.4
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};
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static short[] decryptMethodPattern = new short[] {
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/* 00 */ 0x83, 0xEC, 0x38, // sub esp, 38h
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/* 03 */ 0x53, // push ebx
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/* 04 */ 0xB0, -1, // mov al, ??h
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/* 06 */ 0x88, 0x44, 0x24, 0x2B, // mov [esp+2Bh], al
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/* 0A */ 0x88, 0x44, 0x24, 0x2F, // mov [esp+2Fh], al
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/* 0E */ 0xB0, -1, // mov al, ??h
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/* 10 */ 0x88, 0x44, 0x24, 0x30, // mov [esp+30h], al
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/* 14 */ 0x88, 0x44, 0x24, 0x31, // mov [esp+31h], al
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/* 18 */ 0x88, 0x44, 0x24, 0x33, // mov [esp+33h], al
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/* 1C */ 0x55, // push ebp
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/* 1D */ 0x56, // push esi
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};
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static short[] startMethodNet1xPattern = new short[] {
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/* 00 */ 0x55, // push ebp
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/* 01 */ 0x8B, 0xEC, // mov ebp, esp
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/* 03 */ 0xB9, 0x14, 0x00, 0x00, 0x00, // mov ecx, 14h
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/* 08 */ 0x6A, 0x00, // push 0
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/* 0A */ 0x6A, 0x00, // push 0
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/* 0C */ 0x49, // dec ecx
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/* 0D */ 0x75, 0xF9, // jnz short $-5
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/* 0F */ 0x53, // push ebx
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/* 10 */ 0x56, // push esi
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/* 11 */ 0x57, // push edi
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/* 12 */ 0xB8, -1, -1, -1, -1, // mov eax, offset XXXXXXXX
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/* 17 */ 0xE8, -1, -1, -1, -1, // call YYYYYYYY
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};
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byte[] getKeyData() {
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isNet1x = false;
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for (int i = 0; i < baseOffsets.Length; i++) {
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var code = peImage.offsetReadBytes(baseOffsets[i], decryptMethodPattern.Length);
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if (DeobUtils.isCode(decryptMethodPattern, code))
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return getKeyData(baseOffsets[i]);
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}
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var net1xCode = peImage.offsetReadBytes(0x207E0, startMethodNet1xPattern.Length);
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if (DeobUtils.isCode(startMethodNet1xPattern, net1xCode)) {
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isNet1x = true;
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return new byte[6] { 0x34, 0x38, 0x63, 0x65, 0x7A, 0x35 };
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}
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return null;
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}
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byte[] getKeyData(uint baseOffset) {
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return new byte[6] {
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peImage.offsetReadByte(baseOffset + 5),
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peImage.offsetReadByte(baseOffset + 0xF),
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peImage.offsetReadByte(baseOffset + 0x58),
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peImage.offsetReadByte(baseOffset + 0x6D),
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peImage.offsetReadByte(baseOffset + 0x98),
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peImage.offsetReadByte(baseOffset + 0xA6),
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};
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}
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}
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}
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