/*
Copyright (C) 2011 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.Collections.Generic;
using Mono.Cecil;
using Mono.Cecil.Cil;
namespace de4dot.deobfuscators.SmartAssembly {
class ResourceDecrypterInfo {
ModuleDefinition module;
TypeDefinition simpleZipType;
public byte[] DES_Key { get; private set; }
public byte[] DES_IV { get; private set; }
public byte[] AES_Key { get; private set; }
public byte[] AES_IV { get; private set; }
public bool CanDecrypt {
get { return simpleZipType != null; }
}
public ResourceDecrypterInfo(ModuleDefinition module) {
this.module = module;
}
public ResourceDecrypterInfo(ModuleDefinition module, TypeDefinition simpleZipType, ISimpleDeobfuscator simpleDeobfuscator)
: this(module) {
setSimpleZipType(simpleZipType, simpleDeobfuscator);
}
public void setSimpleZipType(TypeDefinition type, ISimpleDeobfuscator simpleDeobfuscator) {
if (simpleZipType != null || type == null)
return;
simpleZipType = type;
init(simpleDeobfuscator);
}
void init(ISimpleDeobfuscator simpleDeobfuscator) {
var desList = new List(2);
var aesList = new List(2);
if (simpleZipType != null) {
foreach (var method in DotNetUtils.findMethods(simpleZipType.Methods, "System.Byte[]", new string[] { "System.Byte[]" }, true)) {
var instructions = method.Body.Instructions;
simpleDeobfuscator.deobfuscate(method);
for (int i = 0; i <= instructions.Count - 2; i++) {
var ldtoken = instructions[i];
if (ldtoken.OpCode.Code != Code.Ldtoken)
continue;
var field = DotNetUtils.getField(module, ldtoken.Operand as FieldReference);
if (field == null)
continue;
if (field.InitialValue == null)
continue;
var call = instructions[i + 1];
if (call.OpCode.Code != Code.Call)
continue;
var calledMethod = call.Operand as MethodReference;
if (!DotNetUtils.isMethod(calledMethod, "System.Void", "(System.Array,System.RuntimeFieldHandle)"))
continue;
if (field.InitialValue.Length == 8)
desList.Add(field.InitialValue);
else if (field.InitialValue.Length == 16)
aesList.Add(field.InitialValue);
}
}
}
if (desList.Count >= 2) {
DES_Key = desList[desList.Count - 2];
DES_IV = desList[desList.Count - 1];
}
if (aesList.Count >= 2) {
AES_Key = aesList[aesList.Count - 2];
AES_IV = aesList[aesList.Count - 1];
}
}
}
}