/*
Copyright (C) 2011-2012 de4dot@gmail.com
This file is part of de4dot.
de4dot is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
de4dot is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with de4dot. If not, see .
*/
using System;
using System.Collections.Generic;
using Mono.Cecil;
using Mono.MyStuff;
using de4dot.blocks;
using de4dot.PE;
namespace de4dot.code.deobfuscators.CodeWall {
public class DeobfuscatorInfo : DeobfuscatorInfoBase {
public const string THE_NAME = "CodeWall";
public const string THE_TYPE = "cw";
const string DEFAULT_REGEX = @"!^[0-9A-F]{32}$&!^[_<>{}$.`-]$&" + DeobfuscatorBase.DEFAULT_VALID_NAME_REGEX;
BoolOption dumpEmbeddedAssemblies;
BoolOption decryptMainAsm;
public DeobfuscatorInfo()
: base(DEFAULT_REGEX) {
dumpEmbeddedAssemblies = new BoolOption(null, makeArgName("embedded"), "Dump embedded assemblies", true);
decryptMainAsm = new BoolOption(null, makeArgName("decrypt-main"), "Decrypt main embedded assembly", true);
}
public override string Name {
get { return THE_NAME; }
}
public override string Type {
get { return THE_TYPE; }
}
public override IDeobfuscator createDeobfuscator() {
return new Deobfuscator(new Deobfuscator.Options {
ValidNameRegex = validNameRegex.get(),
DumpEmbeddedAssemblies = dumpEmbeddedAssemblies.get(),
DecryptMainAsm = decryptMainAsm.get(),
});
}
protected override IEnumerable getOptionsInternal() {
return new List () {
dumpEmbeddedAssemblies,
decryptMainAsm,
};
}
}
class Deobfuscator : DeobfuscatorBase {
Options options;
MethodsDecrypter methodsDecrypter;
StringDecrypter stringDecrypter;
AssemblyDecrypter assemblyDecrypter;
string obfuscatorName = DeobfuscatorInfo.THE_NAME;
internal class Options : OptionsBase {
public bool DumpEmbeddedAssemblies { get; set; }
public bool DecryptMainAsm { get; set; }
}
public override string Type {
get { return DeobfuscatorInfo.THE_TYPE; }
}
public override string TypeLong {
get { return DeobfuscatorInfo.THE_NAME; }
}
public override string Name {
get { return obfuscatorName; }
}
public Deobfuscator(Options options)
: base(options) {
this.options = options;
}
protected override int detectInternal() {
int val = 0;
int sum = toInt32(methodsDecrypter.Detected) +
toInt32(stringDecrypter.Detected);
if (sum > 0)
val += 100 + 10 * (sum - 1);
// If methods are encrypted, and more than one obfuscator has been used, then CW
// was most likely the last obfuscator used. Increment val so the user doesn't have
// to force CW.
if (methodsDecrypter.Detected)
val += 50;
return val;
}
protected override void scanForObfuscator() {
methodsDecrypter = new MethodsDecrypter(module);
methodsDecrypter.find();
stringDecrypter = new StringDecrypter(module);
stringDecrypter.find();
var version = detectVersion();
if (version != null)
obfuscatorName = DeobfuscatorInfo.THE_NAME + " " + version;
}
string detectVersion() {
if (stringDecrypter.Detected) {
switch (stringDecrypter.TheVersion) {
case StringDecrypter.Version.V30: return "v3.0 - v3.5";
case StringDecrypter.Version.V36: return "v3.6 - v4.1";
}
}
if (methodsDecrypter.Detected)
return "v3.0 - v4.1";
return null;
}
[Flags]
enum DecryptState {
CanDecryptMethods = 1,
CanGetMainAssembly = 2,
}
DecryptState decryptState = DecryptState.CanDecryptMethods | DecryptState.CanGetMainAssembly;
public override bool getDecryptedModule(int count, ref byte[] newFileData, ref DumpedMethods dumpedMethods) {
if ((decryptState & DecryptState.CanDecryptMethods) != 0) {
if (decryptModule(ref newFileData, ref dumpedMethods)) {
ModuleBytes = newFileData;
decryptState &= ~DecryptState.CanDecryptMethods;
return true;
}
}
if (options.DecryptMainAsm && (decryptState & DecryptState.CanGetMainAssembly) != 0) {
newFileData = getMainAssemblyBytes();
if (newFileData != null) {
ModuleBytes = newFileData;
decryptState &= ~DecryptState.CanGetMainAssembly;
decryptState |= DecryptState.CanDecryptMethods;
return true;
}
}
return false;
}
bool decryptModule(ref byte[] newFileData, ref DumpedMethods dumpedMethods) {
if (!methodsDecrypter.Detected)
return false;
byte[] fileData = ModuleBytes ?? DeobUtils.readModule(module);
var peImage = new PeImage(fileData);
if (!methodsDecrypter.decrypt(peImage, ref dumpedMethods))
return false;
newFileData = fileData;
return true;
}
byte[] getMainAssemblyBytes() {
try {
initializeStringDecrypter();
initializeAssemblyDecrypter();
}
catch {
return null;
}
var asm = module.Assembly;
if (asm == null || assemblyDecrypter == null)
return null;
var asmInfo = assemblyDecrypter.findMain(asm.FullName);
if (asmInfo == null)
return null;
assemblyDecrypter.remove(asmInfo);
return asmInfo.data;
}
public override IDeobfuscator moduleReloaded(ModuleDefinition module) {
var newOne = new Deobfuscator(options);
newOne.setModule(module);
newOne.methodsDecrypter = new MethodsDecrypter(module);
newOne.methodsDecrypter.find();
newOne.stringDecrypter = new StringDecrypter(module);
newOne.stringDecrypter.find();
newOne.assemblyDecrypter = assemblyDecrypter;
newOne.ModuleBytes = ModuleBytes;
newOne.decryptState = decryptState;
return newOne;
}
public override void deobfuscateBegin() {
base.deobfuscateBegin();
addAssemblyReferenceToBeRemoved(methodsDecrypter.AssemblyNameReference, "Obfuscator decrypter DLL reference");
initializeStringDecrypter();
initializeAssemblyDecrypter();
dumpEmbeddedAssemblies();
}
bool hasInitializedStringDecrypter = false;
void initializeStringDecrypter() {
if (hasInitializedStringDecrypter)
return;
stringDecrypter.initialize(DeobfuscatedFile);
foreach (var info in stringDecrypter.Infos)
staticStringInliner.add(info.Method, (method, args) => stringDecrypter.decrypt(method, (int)args[0], (int)args[1], (int)args[2]));
DeobfuscatedFile.stringDecryptersAdded();
hasInitializedStringDecrypter = true;
}
void initializeAssemblyDecrypter() {
if (!options.DumpEmbeddedAssemblies || assemblyDecrypter != null)
return;
assemblyDecrypter = new AssemblyDecrypter(module, DeobfuscatedFile, this);
assemblyDecrypter.find();
}
void dumpEmbeddedAssemblies() {
if (assemblyDecrypter == null)
return;
foreach (var info in assemblyDecrypter.AssemblyInfos) {
var asmName = info.assemblySimpleName;
if (info.isEntryPointAssembly)
asmName += "_real";
DeobfuscatedFile.createAssemblyFile(info.data, asmName, info.extension);
}
}
public override void deobfuscateMethodEnd(Blocks blocks) {
methodsDecrypter.deobfuscate(blocks);
base.deobfuscateMethodEnd(blocks);
}
public override void deobfuscateEnd() {
if (CanRemoveStringDecrypterType) {
foreach (var info in stringDecrypter.Infos) {
addResourceToBeRemoved(info.Resource, "Encrypted strings");
addTypeToBeRemoved(info.Type, "String decrypter type");
}
}
base.deobfuscateEnd();
}
public override IEnumerable getStringDecrypterMethods() {
var list = new List();
foreach (var info in stringDecrypter.Infos)
list.Add(info.Method.MetadataToken.ToInt32());
return list;
}
}
}