2011-11-06 19:19:26 +08:00
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/*
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2012-01-10 06:02:47 +08:00
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Copyright (C) 2011-2012 de4dot@gmail.com
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2011-11-06 19:19:26 +08:00
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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.IO;
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using System.Security.Cryptography;
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using System.Text;
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using Mono.Cecil;
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using de4dot.blocks;
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2011-12-09 16:02:06 +08:00
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namespace de4dot.code.deobfuscators.CliSecure {
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2011-11-06 19:19:26 +08:00
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class ResourceDecrypter {
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ModuleDefinition module;
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TypeDefinition rsrcType;
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MethodDefinition rsrcRrrMethod;
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MethodDefinition rsrcDecryptMethod;
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public TypeDefinition Type {
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get { return rsrcType; }
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}
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public MethodDefinition RsrcRrrMethod {
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get { return rsrcRrrMethod; }
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}
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public ResourceDecrypter(ModuleDefinition module) {
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this.module = module;
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}
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public void find() {
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findResourceType();
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}
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void findResourceType() {
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foreach (var type in module.Types) {
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MethodDefinition rrrMethod = null;
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MethodDefinition decryptMethod = null;
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foreach (var method in type.Methods) {
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if (method.Name == "rrr" && DotNetUtils.isMethod(method, "System.Void", "()"))
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rrrMethod = method;
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else if (DotNetUtils.isMethod(method, "System.Reflection.Assembly", "(System.Object,System.ResolveEventArgs)"))
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decryptMethod = method;
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}
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if (rrrMethod == null || decryptMethod == null)
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continue;
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var methodCalls = DotNetUtils.getMethodCallCounts(rrrMethod);
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if (methodCalls.count("System.Void System.ResolveEventHandler::.ctor(System.Object,System.IntPtr)") != 1)
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continue;
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rsrcType = type;
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rsrcRrrMethod = rrrMethod;
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rsrcDecryptMethod = decryptMethod;
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return;
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}
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}
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public EmbeddedResource mergeResources() {
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if (rsrcDecryptMethod == null)
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return null;
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var resource = DotNetUtils.getResource(module, DotNetUtils.getCodeStrings(rsrcDecryptMethod)) as EmbeddedResource;
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if (resource == null)
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return null;
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DeobUtils.decryptAndAddResources(module, resource.Name, () => decryptResource(resource));
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return resource;
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}
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byte[] decryptResource(EmbeddedResource resource) {
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using (var rsrcStream = resource.GetResourceStream()) {
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using (var reader = new BinaryReader(rsrcStream)) {
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var key = reader.ReadString();
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var data = reader.ReadBytes((int)(rsrcStream.Length - rsrcStream.Position));
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var cryptoTransform = new DESCryptoServiceProvider {
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Key = Encoding.ASCII.GetBytes(key),
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IV = Encoding.ASCII.GetBytes(key),
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}.CreateDecryptor();
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var memStream = new MemoryStream(data);
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using (var reader2 = new BinaryReader(new CryptoStream(memStream, cryptoTransform, CryptoStreamMode.Read))) {
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return reader2.ReadBytes((int)memStream.Length);
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}
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}
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}
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}
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}
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}
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