490 lines
14 KiB
C#
490 lines
14 KiB
C#
/*
|
|
Copyright (C) 2011-2015 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 <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
using System;
|
|
using System.Collections.Generic;
|
|
using System.Text;
|
|
using dnlib.IO;
|
|
using dnlib.DotNet;
|
|
using dnlib.DotNet.Emit;
|
|
using de4dot.blocks;
|
|
|
|
namespace de4dot.code.deobfuscators.Confuser {
|
|
class StringDecrypter : IVersionProvider {
|
|
ModuleDefMD module;
|
|
MethodDef decryptMethod;
|
|
EmbeddedResource resource;
|
|
uint magic1, magic2, key1;
|
|
IBinaryReader reader;
|
|
ConfuserVersion version = ConfuserVersion.Unknown;
|
|
Decrypter decrypter;
|
|
|
|
enum ConfuserVersion {
|
|
Unknown,
|
|
v10_r42915,
|
|
v10_r48832,
|
|
v11_r49299,
|
|
v13_r55604_safe,
|
|
v14_r58802_safe,
|
|
v14_r58802_dynamic,
|
|
// The string decrypter "confusion" was disabled from 1.5 r60785 and it was
|
|
// replaced by the constants "confusion".
|
|
}
|
|
|
|
abstract class Decrypter {
|
|
protected StringDecrypter stringDecrypter;
|
|
|
|
protected Decrypter(StringDecrypter stringDecrypter) {
|
|
this.stringDecrypter = stringDecrypter;
|
|
}
|
|
|
|
public abstract string Decrypt(MethodDef caller, int magic);
|
|
}
|
|
|
|
class Decrypter_v10_r42915 : Decrypter {
|
|
int? key;
|
|
|
|
public Decrypter_v10_r42915(StringDecrypter stringDecrypter)
|
|
: this(stringDecrypter, null) {
|
|
}
|
|
|
|
public Decrypter_v10_r42915(StringDecrypter stringDecrypter, int? key)
|
|
: base(stringDecrypter) {
|
|
this.key = key;
|
|
}
|
|
|
|
public override string Decrypt(MethodDef caller, int magic) {
|
|
var reader = stringDecrypter.reader;
|
|
reader.Position = (caller.MDToken.ToInt32() ^ magic) - stringDecrypter.magic1;
|
|
int len = reader.ReadInt32() ^ (int)~stringDecrypter.magic2;
|
|
var bytes = reader.ReadBytes(len);
|
|
var rand = new Random(key == null ? caller.MDToken.ToInt32() : key.Value);
|
|
|
|
int mask = 0;
|
|
for (int i = 0; i < bytes.Length; i++) {
|
|
byte b = bytes[i];
|
|
bytes[i] = (byte)(b ^ (rand.Next() & mask));
|
|
mask += b;
|
|
}
|
|
return Encoding.UTF8.GetString(bytes);
|
|
}
|
|
}
|
|
|
|
class Decrypter_v10_r48832 : Decrypter {
|
|
PolyConstantsReader constReader;
|
|
|
|
public Decrypter_v10_r48832(StringDecrypter stringDecrypter)
|
|
: base(stringDecrypter) {
|
|
}
|
|
|
|
public override string Decrypt(MethodDef caller, int magic) {
|
|
var reader = stringDecrypter.reader;
|
|
reader.Position = (caller.MDToken.ToInt32() ^ magic) - stringDecrypter.magic1;
|
|
int len = reader.ReadInt32() ^ (int)~stringDecrypter.magic2;
|
|
var rand = new Random(caller.MDToken.ToInt32());
|
|
|
|
var instrs = stringDecrypter.decryptMethod.Body.Instructions;
|
|
constReader = new PolyConstantsReader(instrs, false);
|
|
int polyIndex = ConfuserUtils.FindCallMethod(instrs, 0, Code.Callvirt, "System.Int64 System.IO.BinaryReader::ReadInt64()");
|
|
if (polyIndex < 0)
|
|
throw new ApplicationException("Could not find start of decrypt code");
|
|
|
|
var decrypted = new byte[len];
|
|
for (int i = 0; i < len; i += 8) {
|
|
constReader.Arg = reader.ReadInt64();
|
|
int index = polyIndex;
|
|
long val;
|
|
if (!constReader.GetInt64(ref index, out val) || instrs[index].OpCode.Code != Code.Conv_I8)
|
|
throw new ApplicationException("Could not get string int64 value");
|
|
Array.Copy(BitConverter.GetBytes(val ^ rand.Next()), 0, decrypted, i, Math.Min(8, len - i));
|
|
}
|
|
|
|
return Encoding.Unicode.GetString(decrypted);
|
|
}
|
|
}
|
|
|
|
class Decrypter_v11_r49299 : Decrypter {
|
|
public Decrypter_v11_r49299(StringDecrypter stringDecrypter)
|
|
: base(stringDecrypter) {
|
|
}
|
|
|
|
public override string Decrypt(MethodDef caller, int magic) {
|
|
var reader = stringDecrypter.reader;
|
|
reader.Position = (caller.MDToken.ToInt32() ^ magic) - stringDecrypter.magic1;
|
|
int len = reader.ReadInt32() ^ (int)~stringDecrypter.magic2;
|
|
var decrypted = new byte[len];
|
|
|
|
int startIndex, endIndex;
|
|
if (!FindPolyStartEndIndexes(out startIndex, out endIndex))
|
|
throw new ApplicationException("Could not get start/end indexes");
|
|
|
|
var constReader = new Arg64ConstantsReader(stringDecrypter.decryptMethod.Body.Instructions, false);
|
|
ConfuserUtils.DecryptCompressedInt32Data(constReader, startIndex, endIndex, reader, decrypted);
|
|
return Encoding.Unicode.GetString(decrypted);
|
|
}
|
|
|
|
bool FindPolyStartEndIndexes(out int startIndex, out int endIndex) {
|
|
startIndex = 0;
|
|
endIndex = 0;
|
|
|
|
var local = FindLocal(stringDecrypter.decryptMethod);
|
|
if (local == null)
|
|
return false;
|
|
|
|
if ((endIndex = FindEndIndex(stringDecrypter.decryptMethod)) < 0)
|
|
return false;
|
|
|
|
if ((startIndex = FindStartIndex(stringDecrypter.decryptMethod, endIndex)) < 0)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static Local FindLocal(MethodDef method) {
|
|
var instrs = method.Body.Instructions;
|
|
for (int i = 0; i < instrs.Count - 3; i++) {
|
|
if (instrs[i].OpCode.Code != Code.And)
|
|
continue;
|
|
if (instrs[i + 1].OpCode.Code != Code.Shl)
|
|
continue;
|
|
if (instrs[i + 2].OpCode.Code != Code.Or)
|
|
continue;
|
|
if (!instrs[i + 3].IsStloc())
|
|
continue;
|
|
return instrs[i + 3].GetLocal(method.Body.Variables);
|
|
}
|
|
return null;
|
|
}
|
|
|
|
static int FindEndIndex(MethodDef method) {
|
|
var instrs = method.Body.Instructions;
|
|
for (int i = 0; i < instrs.Count - 5; i++) {
|
|
if (instrs[i].OpCode.Code != Code.Conv_U1)
|
|
continue;
|
|
if (instrs[i + 1].OpCode.Code != Code.Stelem_I1)
|
|
continue;
|
|
if (!instrs[i + 2].IsLdloc())
|
|
continue;
|
|
if (!instrs[i + 3].IsLdcI4())
|
|
continue;
|
|
if (instrs[i + 4].OpCode.Code != Code.Add)
|
|
continue;
|
|
if (!instrs[i + 5].IsStloc())
|
|
continue;
|
|
return i;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
static int FindStartIndex(MethodDef method, int endIndex) {
|
|
var instrs = method.Body.Instructions;
|
|
for (int i = endIndex; i >= 0; i--) {
|
|
var instr = instrs[i];
|
|
if (instr.OpCode.FlowControl != FlowControl.Next)
|
|
break;
|
|
if (instr.OpCode.Code == Code.Conv_I8)
|
|
return i;
|
|
}
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
class PolyConstantsReader : ConstantsReader {
|
|
long arg;
|
|
|
|
public long Arg {
|
|
get { return arg; }
|
|
set { arg = value; }
|
|
}
|
|
|
|
public PolyConstantsReader(IList<Instruction> instrs, bool emulateConvInstrs)
|
|
: base(instrs, emulateConvInstrs) {
|
|
}
|
|
|
|
protected override bool ProcessInstructionInt64(ref int index, Stack<ConstantInfo<long>> stack) {
|
|
int i = index;
|
|
|
|
if (instructions[i].IsLdloc()) {
|
|
i++;
|
|
if (i >= instructions.Count)
|
|
return false;
|
|
}
|
|
var callvirt = instructions[i];
|
|
if (callvirt.OpCode.Code != Code.Callvirt)
|
|
return false;
|
|
var calledMethod = callvirt.Operand as IMethod;
|
|
if (calledMethod == null || calledMethod.FullName != "System.Int64 System.IO.BinaryReader::ReadInt64()")
|
|
return false;
|
|
|
|
stack.Push(new ConstantInfo<long>(index, arg));
|
|
index = i + 1;
|
|
return true;
|
|
}
|
|
}
|
|
|
|
public EmbeddedResource Resource {
|
|
get { return resource; }
|
|
}
|
|
|
|
public MethodDef Method {
|
|
get { return decryptMethod; }
|
|
}
|
|
|
|
public bool Detected {
|
|
get { return decryptMethod != null; }
|
|
}
|
|
|
|
public StringDecrypter(ModuleDefMD module) {
|
|
this.module = module;
|
|
}
|
|
|
|
static string[] requiredLocals = new string[] {
|
|
"System.Byte[]",
|
|
"System.IO.BinaryReader",
|
|
"System.Reflection.Assembly",
|
|
};
|
|
public void Find(ISimpleDeobfuscator simpleDeobfuscator) {
|
|
var type = DotNetUtils.GetModuleType(module);
|
|
if (type == null)
|
|
return;
|
|
foreach (var method in type.Methods) {
|
|
if (!method.IsStatic || method.Body == null)
|
|
continue;
|
|
if (!DotNetUtils.IsMethod(method, "System.String", "(System.Int32)"))
|
|
continue;
|
|
var localTypes = new LocalTypes(method);
|
|
if (!localTypes.All(requiredLocals))
|
|
continue;
|
|
|
|
simpleDeobfuscator.Deobfuscate(method);
|
|
|
|
bool foundOldMagic1;
|
|
if (FindMagic1(method, out magic1))
|
|
foundOldMagic1 = true;
|
|
else if (FindNewMagic1(method, out magic1))
|
|
foundOldMagic1 = false;
|
|
else
|
|
continue;
|
|
if (!FindMagic2(method, out magic2))
|
|
continue;
|
|
|
|
version = ConfuserVersion.Unknown;
|
|
if (DotNetUtils.CallsMethod(method, "System.Text.Encoding System.Text.Encoding::get_UTF8()")) {
|
|
if (foundOldMagic1) {
|
|
if (DotNetUtils.CallsMethod(method, "System.Object System.AppDomain::GetData(System.String)"))
|
|
version = ConfuserVersion.v13_r55604_safe;
|
|
else
|
|
version = ConfuserVersion.v10_r42915;
|
|
}
|
|
else {
|
|
if (!FindSafeKey1(method, out key1))
|
|
continue;
|
|
version = ConfuserVersion.v14_r58802_safe;
|
|
}
|
|
}
|
|
else if (!localTypes.Exists("System.Random")) {
|
|
if (foundOldMagic1)
|
|
version = ConfuserVersion.v11_r49299;
|
|
else
|
|
version = ConfuserVersion.v14_r58802_dynamic;
|
|
}
|
|
else if (localTypes.Exists("System.Collections.Generic.Dictionary`2<System.Int32,System.String>"))
|
|
version = ConfuserVersion.v10_r48832;
|
|
if (version == ConfuserVersion.Unknown)
|
|
continue;
|
|
|
|
decryptMethod = method;
|
|
break;
|
|
}
|
|
}
|
|
|
|
EmbeddedResource FindResource(MethodDef method) {
|
|
return DotNetUtils.GetResource(module, DotNetUtils.GetCodeStrings(method)) as EmbeddedResource;
|
|
}
|
|
|
|
static bool FindMagic1(MethodDef method, out uint magic) {
|
|
var instrs = method.Body.Instructions;
|
|
for (int i = 0; i < instrs.Count; i++) {
|
|
int index = ConfuserUtils.FindCallMethod(instrs, i, Code.Callvirt, "System.Byte[] System.IO.BinaryReader::ReadBytes(System.Int32)");
|
|
if (index < 0)
|
|
break;
|
|
if (index < 4)
|
|
continue;
|
|
|
|
index -= 4;
|
|
if (!instrs[index].IsLdarg())
|
|
continue;
|
|
if (instrs[index + 1].OpCode.Code != Code.Xor)
|
|
continue;
|
|
var ldci4 = instrs[index + 2];
|
|
if (!ldci4.IsLdcI4())
|
|
continue;
|
|
if (instrs[index + 3].OpCode.Code != Code.Sub)
|
|
continue;
|
|
|
|
magic = (uint)ldci4.GetLdcI4Value();
|
|
return true;
|
|
}
|
|
magic = 0;
|
|
return false;
|
|
}
|
|
|
|
static bool FindNewMagic1(MethodDef method, out uint magic) {
|
|
var instrs = method.Body.Instructions;
|
|
for (int i = 0; i < instrs.Count - 4; i++) {
|
|
if (instrs[i].OpCode.Code != Code.Ldarg_0)
|
|
continue;
|
|
if (instrs[i + 1].OpCode.Code != Code.Xor)
|
|
continue;
|
|
var ldci4 = instrs[i + 2];
|
|
if (!ldci4.IsLdcI4())
|
|
continue;
|
|
if (instrs[i + 3].OpCode.Code != Code.Sub)
|
|
continue;
|
|
if (!instrs[i + 4].IsStloc())
|
|
continue;
|
|
|
|
magic = (uint)ldci4.GetLdcI4Value();
|
|
return true;
|
|
}
|
|
magic = 0;
|
|
return false;
|
|
}
|
|
|
|
static bool FindMagic2(MethodDef method, out uint magic) {
|
|
var instrs = method.Body.Instructions;
|
|
for (int i = 0; i < instrs.Count; i++) {
|
|
int index = ConfuserUtils.FindCallMethod(instrs, i, Code.Callvirt, "System.UInt32 System.IO.BinaryReader::ReadUInt32()");
|
|
if (index < 0)
|
|
break;
|
|
if (index + 4 >= instrs.Count)
|
|
continue;
|
|
|
|
if (instrs[index + 1].OpCode.Code != Code.Not)
|
|
continue;
|
|
var ldci4 = instrs[index + 2];
|
|
if (!ldci4.IsLdcI4())
|
|
continue;
|
|
if (instrs[index + 3].OpCode.Code != Code.Xor)
|
|
continue;
|
|
if (!instrs[index + 4].IsStloc())
|
|
continue;
|
|
|
|
magic = (uint)ldci4.GetLdcI4Value();
|
|
return true;
|
|
}
|
|
magic = 0;
|
|
return false;
|
|
}
|
|
|
|
static bool FindSafeKey1(MethodDef method, out uint key) {
|
|
var instrs = method.Body.Instructions;
|
|
for (int i = 0; i < instrs.Count; i++) {
|
|
int index = ConfuserUtils.FindCallMethod(instrs, i, Code.Newobj, "System.Void System.Random::.ctor(System.Int32)");
|
|
if (index < 0)
|
|
break;
|
|
if (index == 0)
|
|
continue;
|
|
|
|
var ldci4 = instrs[index - 1];
|
|
if (!ldci4.IsLdcI4())
|
|
continue;
|
|
|
|
key = (uint)ldci4.GetLdcI4Value();
|
|
return true;
|
|
}
|
|
key = 0;
|
|
return false;
|
|
}
|
|
|
|
public void Initialize() {
|
|
if (decryptMethod == null)
|
|
return;
|
|
|
|
resource = FindResource(decryptMethod);
|
|
if (resource == null)
|
|
throw new ApplicationException("Could not find encrypted strings resource");
|
|
reader = MemoryImageStream.Create(DeobUtils.Inflate(resource.GetResourceData(), true));
|
|
|
|
switch (version) {
|
|
case ConfuserVersion.v10_r42915:
|
|
case ConfuserVersion.v13_r55604_safe:
|
|
decrypter = new Decrypter_v10_r42915(this);
|
|
break;
|
|
|
|
case ConfuserVersion.v10_r48832:
|
|
decrypter = new Decrypter_v10_r48832(this);
|
|
break;
|
|
|
|
case ConfuserVersion.v11_r49299:
|
|
case ConfuserVersion.v14_r58802_dynamic:
|
|
decrypter = new Decrypter_v11_r49299(this);
|
|
break;
|
|
|
|
case ConfuserVersion.v14_r58802_safe:
|
|
decrypter = new Decrypter_v10_r42915(this, (int)key1);
|
|
break;
|
|
|
|
default:
|
|
throw new ApplicationException("Invalid version");
|
|
}
|
|
}
|
|
|
|
public string Decrypt(MethodDef caller, int magic) {
|
|
return decrypter.Decrypt(caller, magic);
|
|
}
|
|
|
|
public bool GetRevisionRange(out int minRev, out int maxRev) {
|
|
switch (version) {
|
|
case ConfuserVersion.Unknown:
|
|
minRev = maxRev = 0;
|
|
return false;
|
|
|
|
case ConfuserVersion.v10_r42915:
|
|
minRev = 42915;
|
|
maxRev = 48771;
|
|
return true;
|
|
|
|
case ConfuserVersion.v10_r48832:
|
|
minRev = 48832;
|
|
maxRev = 49238;
|
|
return true;
|
|
|
|
case ConfuserVersion.v11_r49299:
|
|
minRev = 49299;
|
|
maxRev = 58741;
|
|
return true;
|
|
|
|
case ConfuserVersion.v13_r55604_safe:
|
|
minRev = 55604;
|
|
maxRev = 58741;
|
|
return true;
|
|
|
|
case ConfuserVersion.v14_r58802_safe:
|
|
case ConfuserVersion.v14_r58802_dynamic:
|
|
minRev = 58802;
|
|
maxRev = 60408;
|
|
return true;
|
|
|
|
default: throw new ApplicationException("Invalid version");
|
|
}
|
|
}
|
|
}
|
|
}
|