2012-07-30 20:11:04 +08:00
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/*
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Copyright (C) 2011-2012 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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2012-08-01 01:56:10 +08:00
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using System;
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2012-08-01 17:41:31 +08:00
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using System.Collections.Generic;
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2012-08-01 01:56:10 +08:00
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using System.IO;
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2012-07-30 20:11:04 +08:00
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using Mono.Cecil;
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using Mono.Cecil.Cil;
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using de4dot.blocks;
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namespace de4dot.code.deobfuscators.Confuser {
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2012-08-01 17:41:31 +08:00
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class EmbeddedAssemblyInfo {
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public readonly byte[] data;
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public readonly string asmFullName;
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public readonly string asmSimpleName;
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public readonly string extension;
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public readonly EmbeddedResource resource;
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public EmbeddedAssemblyInfo(EmbeddedResource resource, byte[] data, string asmFullName, string extension) {
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this.resource = resource;
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this.data = data;
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this.asmFullName = asmFullName;
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this.asmSimpleName = Utils.getAssemblySimpleName(asmFullName);
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this.extension = extension;
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}
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public override string ToString() {
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return asmFullName;
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}
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}
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2012-07-30 20:11:04 +08:00
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class Unpacker {
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ModuleDefinition module;
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2012-08-01 17:41:31 +08:00
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EmbeddedResource mainAsmResource;
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uint key0, key1;
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2012-08-01 01:56:10 +08:00
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ConfuserVersion version = ConfuserVersion.Unknown;
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2012-08-01 17:41:31 +08:00
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MethodDefinition asmResolverMethod;
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2012-08-01 01:56:10 +08:00
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enum ConfuserVersion {
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Unknown,
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v10_r42915,
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v14_r58564,
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2012-08-01 17:41:31 +08:00
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v14_r58802,
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2012-08-01 20:05:29 +08:00
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v14_r58852,
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2012-08-02 14:40:52 +08:00
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v15_r60785,
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2012-08-01 01:56:10 +08:00
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}
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2012-07-30 20:11:04 +08:00
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public bool Detected {
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2012-08-01 17:41:31 +08:00
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get { return mainAsmResource != null; }
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2012-07-30 20:11:04 +08:00
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}
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public Unpacker(ModuleDefinition module) {
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this.module = module;
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}
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static string[] requiredFields = new string[] {
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"System.String",
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};
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static string[] requiredEntryPointLocals = new string[] {
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"System.Byte[]",
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"System.Int32",
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"System.IO.BinaryReader",
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"System.IO.Stream",
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};
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public void find(ISimpleDeobfuscator simpleDeobfuscator, IDeobfuscator deob) {
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var entryPoint = module.EntryPoint;
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if (entryPoint == null)
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return;
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if (!new LocalTypes(entryPoint).all(requiredEntryPointLocals))
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return;
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var type = entryPoint.DeclaringType;
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if (!new FieldTypes(type).all(requiredFields))
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return;
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2012-08-01 01:56:10 +08:00
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var decyptMethod = findDecryptMethod(type);
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if (decyptMethod == null)
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2012-07-30 20:11:04 +08:00
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return;
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2012-08-02 14:40:52 +08:00
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var decryptLocals = new LocalTypes(decyptMethod);
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if (decryptLocals.exists("System.IO.MemoryStream"))
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2012-08-01 01:56:10 +08:00
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version = ConfuserVersion.v10_r42915;
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else
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version = ConfuserVersion.v14_r58564;
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2012-07-30 20:11:04 +08:00
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var cctor = DotNetUtils.getMethod(type, ".cctor");
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if (cctor == null)
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return;
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2012-08-01 17:41:31 +08:00
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if ((asmResolverMethod = findAssemblyResolverMethod(entryPoint.DeclaringType)) != null) {
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version = ConfuserVersion.v14_r58802;
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simpleDeobfuscator.deobfuscate(asmResolverMethod);
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if (!findKey1(asmResolverMethod, out key1))
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return;
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}
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switch (version) {
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case ConfuserVersion.v10_r42915:
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break;
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case ConfuserVersion.v14_r58564:
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case ConfuserVersion.v14_r58802:
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2012-08-01 01:56:10 +08:00
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simpleDeobfuscator.deobfuscate(decyptMethod);
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2012-08-01 20:05:29 +08:00
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if (findKey0_v14_r58564(decyptMethod, out key0))
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break;
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if (findKey0_v14_r58852(decyptMethod, out key0)) {
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2012-08-02 14:40:52 +08:00
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if (!decryptLocals.exists("System.Security.Cryptography.RijndaelManaged")) {
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version = ConfuserVersion.v14_r58852;
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break;
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}
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version = ConfuserVersion.v15_r60785;
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2012-08-01 20:05:29 +08:00
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break;
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}
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throw new ApplicationException("Could not find magic");
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2012-08-01 17:41:31 +08:00
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default:
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throw new ApplicationException("Invalid version");
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2012-08-01 01:56:10 +08:00
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}
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2012-07-30 20:11:04 +08:00
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simpleDeobfuscator.deobfuscate(cctor);
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simpleDeobfuscator.decryptStrings(cctor, deob);
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2012-08-01 17:41:31 +08:00
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mainAsmResource = findResource(cctor);
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if (mainAsmResource == null)
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throw new ApplicationException("Could not find main assembly resource");
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2012-07-30 20:11:04 +08:00
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}
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2012-08-01 17:41:31 +08:00
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static MethodDefinition findAssemblyResolverMethod(TypeDefinition type) {
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foreach (var method in type.Methods) {
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if (!method.IsStatic || method.Body == null)
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continue;
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if (!DotNetUtils.isMethod(method, "System.Reflection.Assembly", "(System.Object,System.ResolveEventArgs)"))
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continue;
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return method;
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}
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return null;
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}
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2012-08-01 20:05:29 +08:00
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static bool findKey0_v14_r58564(MethodDefinition method, out uint key) {
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2012-08-01 01:56:10 +08:00
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 2; i++) {
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if (instrs[i].OpCode.Code != Code.Xor)
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continue;
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var ldci4 = instrs[i + 1];
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if (!DotNetUtils.isLdcI4(ldci4))
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continue;
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if (instrs[i + 2].OpCode.Code != Code.Xor)
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continue;
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key = (uint)DotNetUtils.getLdcI4Value(ldci4);
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return true;
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}
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key = 0;
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return false;
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}
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2012-08-01 20:05:29 +08:00
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static bool findKey0_v14_r58852(MethodDefinition method, out uint key) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 3; i++) {
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var ldci4_1 = instrs[i];
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if (!DotNetUtils.isLdcI4(ldci4_1))
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continue;
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if (!DotNetUtils.isStloc(instrs[i + 1]))
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continue;
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var ldci4_2 = instrs[i + 2];
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if (!DotNetUtils.isLdcI4(ldci4_2) && DotNetUtils.getLdcI4Value(ldci4_2) != 0)
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continue;
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if (!DotNetUtils.isStloc(instrs[i + 3]))
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continue;
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key = (uint)DotNetUtils.getLdcI4Value(ldci4_1);
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return true;
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}
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key = 0;
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return false;
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}
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2012-08-01 17:41:31 +08:00
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static bool findKey1(MethodDefinition method, out uint key) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count - 4; i++) {
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if (instrs[i].OpCode.Code != Code.Ldelem_U1)
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continue;
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var ldci4 = instrs[i + 1];
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if (!DotNetUtils.isLdcI4(ldci4))
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continue;
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if (instrs[i + 2].OpCode.Code != Code.Xor)
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continue;
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if (!DotNetUtils.isLdloc(instrs[i + 3]))
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continue;
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if (instrs[i + 4].OpCode.Code != Code.Xor)
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continue;
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key = (uint)DotNetUtils.getLdcI4Value(ldci4);
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return true;
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}
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key = 0;
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return false;
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}
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2012-07-30 20:11:04 +08:00
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EmbeddedResource findResource(MethodDefinition method) {
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return DotNetUtils.getResource(module, DotNetUtils.getCodeStrings(method)) as EmbeddedResource;
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}
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static string[] requiredDecryptLocals = new string[] {
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"System.Byte[]",
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"System.IO.Compression.DeflateStream",
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};
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static MethodDefinition findDecryptMethod(TypeDefinition type) {
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foreach (var method in type.Methods) {
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if (!method.IsStatic || method.Body == null)
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continue;
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if (!DotNetUtils.isMethod(method, "System.Byte[]", "(System.Byte[])"))
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continue;
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if (!new LocalTypes(method).all(requiredDecryptLocals))
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continue;
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return method;
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}
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return null;
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}
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2012-08-01 17:41:31 +08:00
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public EmbeddedAssemblyInfo unpackMainAssembly() {
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if (mainAsmResource == null)
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2012-07-30 20:11:04 +08:00
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return null;
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2012-08-01 17:41:31 +08:00
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return createEmbeddedAssemblyInfo(mainAsmResource, decrypt(mainAsmResource));
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}
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public List<EmbeddedAssemblyInfo> getEmbeddedAssemblyInfos() {
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var infos = new List<EmbeddedAssemblyInfo>();
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foreach (var rsrc in module.Resources) {
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var resource = rsrc as EmbeddedResource;
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if (resource == null || resource == mainAsmResource)
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continue;
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try {
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infos.Add(createEmbeddedAssemblyInfo(resource, decrypt(resource)));
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}
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catch {
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}
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}
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return infos;
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}
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static EmbeddedAssemblyInfo createEmbeddedAssemblyInfo(EmbeddedResource resource, byte[] data) {
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var mod = ModuleDefinition.ReadModule(new MemoryStream(data));
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return new EmbeddedAssemblyInfo(resource, data, mod.Assembly.Name.FullName, DeobUtils.getExtension(mod.Kind));
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}
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byte[] decrypt(EmbeddedResource resource) {
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2012-07-30 20:11:04 +08:00
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var data = resource.GetResourceData();
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2012-08-01 20:05:29 +08:00
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switch (version) {
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case ConfuserVersion.v10_r42915: return decrypt_v10_r42915(data);
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case ConfuserVersion.v14_r58564: return decrypt_v14_r58564(data);
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case ConfuserVersion.v14_r58802: return decrypt_v14_r58564(data);
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case ConfuserVersion.v14_r58852: return decrypt_v14_r58852(data);
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2012-08-02 14:40:52 +08:00
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case ConfuserVersion.v15_r60785: return decrypt_v15_r60785(data);
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2012-08-01 20:05:29 +08:00
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default: throw new ApplicationException("Unknown version");
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}
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}
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byte[] decrypt_v10_r42915(byte[] data) {
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2012-07-30 20:11:04 +08:00
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for (int i = 0; i < data.Length; i++)
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2012-08-01 17:41:31 +08:00
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data[i] ^= (byte)(i ^ key0);
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2012-08-01 20:05:29 +08:00
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return DeobUtils.inflate(data, true);
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}
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2012-08-01 01:56:10 +08:00
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2012-08-01 20:05:29 +08:00
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byte[] decrypt_v14_r58564(byte[] data) {
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var reader = new BinaryReader(new MemoryStream(decrypt_v10_r42915(data)));
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return reader.ReadBytes(reader.ReadInt32());
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}
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2012-08-01 01:56:10 +08:00
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2012-08-01 20:05:29 +08:00
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byte[] decrypt_v14_r58852(byte[] data) {
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var reader = new BinaryReader(new MemoryStream(DeobUtils.inflate(data, true)));
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data = reader.ReadBytes(reader.ReadInt32());
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for (int i = 0; i < data.Length; i++) {
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if ((i & 1) == 0)
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data[i] ^= (byte)((key0 & 0xF) - i);
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else
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data[i] ^= (byte)((key0 >> 4) + i);
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data[i] -= (byte)i;
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|
|
|
}
|
2012-07-30 20:11:04 +08:00
|
|
|
|
return data;
|
|
|
|
|
}
|
2012-08-01 17:41:31 +08:00
|
|
|
|
|
2012-08-02 14:40:52 +08:00
|
|
|
|
byte[] decrypt_v15_r60785(byte[] data) {
|
|
|
|
|
var reader = new BinaryReader(new MemoryStream(DeobUtils.inflate(data, true)));
|
|
|
|
|
var encrypted = reader.ReadBytes(reader.ReadInt32());
|
|
|
|
|
var iv = reader.ReadBytes(reader.ReadInt32());
|
|
|
|
|
var key = reader.ReadBytes(reader.ReadInt32());
|
|
|
|
|
for (int i = 0; i < key.Length; i += 4) {
|
|
|
|
|
key[i] ^= (byte)key0;
|
|
|
|
|
key[i + 1] ^= (byte)(key0 >> 8);
|
|
|
|
|
key[i + 2] ^= (byte)(key0 >> 16);
|
|
|
|
|
key[i + 3] ^= (byte)(key0 >> 24);
|
|
|
|
|
}
|
|
|
|
|
reader = new BinaryReader(new MemoryStream(DeobUtils.aesDecrypt(encrypted, key, iv)));
|
|
|
|
|
return reader.ReadBytes(reader.ReadInt32());
|
|
|
|
|
}
|
|
|
|
|
|
2012-08-01 17:41:31 +08:00
|
|
|
|
public void deobfuscate(Blocks blocks) {
|
|
|
|
|
if (asmResolverMethod == null)
|
|
|
|
|
return;
|
|
|
|
|
if (blocks.Method != DotNetUtils.getModuleTypeCctor(module))
|
|
|
|
|
return;
|
|
|
|
|
ConfuserUtils.removeResourceHookCode(blocks, asmResolverMethod);
|
|
|
|
|
}
|
2012-07-30 20:11:04 +08:00
|
|
|
|
}
|
|
|
|
|
}
|