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Support Eazfuscator.NET 3.5 string encrypter

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de4dot 2012-12-11 00:23:16 +01:00
parent b8430ea2e3
commit 245d875d5f
4 changed files with 365 additions and 0 deletions
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1
de4dot.code/de4dot.code.csproj
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@ -153,6 +153,7 @@
<Compile Include="deobfuscators\DeobUtils.cs" />
<Compile Include="deobfuscators\Dotfuscator\Deobfuscator.cs" />
<Compile Include="deobfuscators\Dotfuscator\StringDecrypter.cs" />
<Compile Include="deobfuscators\Eazfuscator_NET\Dynocode.cs" />
<Compile Include="deobfuscators\MyPEImage.cs" />
<Compile Include="deobfuscators\dotNET_Reactor\v3\AntiStrongName.cs" />
<Compile Include="deobfuscators\dotNET_Reactor\v3\ApplicationModeDecrypter.cs" />

1
de4dot.code/deobfuscators/Eazfuscator_NET/Deobfuscator.cs
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@ -156,6 +156,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
if (CanRemoveStringDecrypterType) {
addTypesToBeRemoved(stringDecrypter.Types, "String decrypter type");
addTypeToBeRemoved(decrypterType.Type, "Decrypter type");
addTypesToBeRemoved(stringDecrypter.DynocodeTypes, "Dynocode type");
addResourceToBeRemoved(stringDecrypter.Resource, "Encrypted strings");
}
addTypeToBeRemoved(assemblyResolver.Type, "Assembly resolver type");

286
de4dot.code/deobfuscators/Eazfuscator_NET/Dynocode.cs Normal file
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@ -0,0 +1,286 @@
/*
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 <http://www.gnu.org/licenses/>.
*/
using System.Collections.Generic;
using dot10.DotNet;
using dot10.DotNet.Emit;
using de4dot.blocks;
namespace de4dot.code.deobfuscators.Eazfuscator_NET {
interface IDynocodeGenerator {
IEnumerable<int> getValues(int input);
}
// Something added in EF 3.5 which they call Dynocode. The string decrypter can now
// call some iterator classes that will return some integers that it will use to
// XOR some key.
class Dynocode {
ISimpleDeobfuscator simpleDeobfuscator;
Dictionary<TypeDef, IDynocodeGenerator> typeToDCGen = new Dictionary<TypeDef, IDynocodeGenerator>();
class DCGen1 : IDynocodeGenerator {
public int magic1;
public int magic2;
public int magic3;
public int magic4;
public int magic5;
public int magic6;
public int magic7;
public IEnumerable<int> getValues(int input) {
yield return magic1;
yield return magic2;
yield return input ^ magic3;
yield return magic4;
yield return magic5;
yield return magic6;
yield return input ^ magic7;
}
}
class DCGen2 : IDynocodeGenerator {
public int magic1;
public IEnumerable<int> getValues(int input) {
int x = 0;
int y = 1;
while (true) {
yield return y;
if (--input == 0)
break;
int tmp = y;
y = (x + y + input) ^ magic1;
x = tmp;
}
}
}
class DCGen3 : IDynocodeGenerator {
public int magic1;
public int magic2;
public DCGen2 dc2;
public IEnumerable<int> getValues(int input) {
int i = 7;
foreach (var val in dc2.getValues(input)) {
int x = val ^ input;
if ((x % 4) == 0)
x ^= magic1;
if ((x % 16) == 0)
x ^= magic2;
yield return x;
if (--i == 0)
break;
}
}
}
public IEnumerable<TypeDef> Types {
get { return typeToDCGen.Keys; }
}
public Dynocode(ISimpleDeobfuscator simpleDeobfuscator) {
this.simpleDeobfuscator = simpleDeobfuscator;
}
public IDynocodeGenerator getDynocodeGenerator(TypeDef type) {
if (type == null)
return null;
var dt = type.DeclaringType;
if (dt == null)
return null;
IDynocodeGenerator dcGen;
if (typeToDCGen.TryGetValue(type, out dcGen))
return dcGen;
if (dt.NestedTypes.Count == 1)
dcGen = getDCGen1(type);
else if (dt.NestedTypes.Count == 2)
dcGen = getDCGen3(type);
typeToDCGen[type] = dcGen;
return dcGen;
}
DCGen1 getDCGen1(TypeDef type) {
var method = getMoveNext(type);
if (method == null)
return null;
simpleDeobfuscator.deobfuscate(method);
var swLabels = getSwitchLabels(method);
if (swLabels == null || swLabels.Count < 7)
return null;
var dcGen = new DCGen1();
if (!getMagicDC1(method, swLabels[0], out dcGen.magic1))
return null;
if (!getMagicDC1(method, swLabels[1], out dcGen.magic2))
return null;
if (!getMagicXorDC1(method, swLabels[2], out dcGen.magic3))
return null;
if (!getMagicDC1(method, swLabels[3], out dcGen.magic4))
return null;
if (!getMagicDC1(method, swLabels[4], out dcGen.magic5))
return null;
if (!getMagicDC1(method, swLabels[5], out dcGen.magic6))
return null;
if (!getMagicXorDC1(method, swLabels[6], out dcGen.magic7))
return null;
return dcGen;
}
static IList<Instruction> getSwitchLabels(MethodDef method) {
foreach (var instr in method.Body.Instructions) {
if (instr.OpCode.Code != Code.Switch)
continue;
return instr.Operand as IList<Instruction>;
}
return null;
}
static bool getMagicDC1(MethodDef method, Instruction target, out int magic) {
magic = 0;
var instrs = method.Body.Instructions;
int index = instrs.IndexOf(target);
if (index < 0)
return false;
for (int i = index; i < instrs.Count - 3; i++) {
var instr = instrs[i];
if (instr.OpCode.FlowControl != FlowControl.Next)
return false;
if (instr.OpCode.Code != Code.Stfld)
continue;
if (instrs[i + 1].OpCode.Code != Code.Ldarg_0)
continue;
var ldci4 = instrs[i + 2];
if (!ldci4.IsLdcI4())
continue;
if (instrs[i + 3].OpCode.Code != Code.Stfld)
continue;
magic = ldci4.GetLdcI4Value();
return true;
}
return false;
}
static bool getMagicXorDC1(MethodDef method, Instruction target, out int magic) {
magic = 0;
var instrs = method.Body.Instructions;
int index = instrs.IndexOf(target);
if (index < 0)
return false;
for (int i = index; i < instrs.Count - 2; i++) {
var instr = instrs[i];
if (instr.OpCode.FlowControl != FlowControl.Next)
return false;
if (!instr.IsLdcI4())
continue;
if (instrs[i + 1].OpCode.Code != Code.Xor)
continue;
if (instrs[i + 2].OpCode.Code != Code.Stfld)
continue;
magic = instr.GetLdcI4Value();
return true;
}
return false;
}
DCGen3 getDCGen3(TypeDef type) {
var method = getMoveNext(type);
if (method == null)
return null;
simpleDeobfuscator.deobfuscate(method);
var dcGen = new DCGen3();
int index = 0;
if (!getMagicDC3(method, ref index, out dcGen.magic1))
return null;
if (!getMagicDC3(method, ref index, out dcGen.magic2))
return null;
var dt = type.DeclaringType;
dcGen.dc2 = getDCGen2(dt.NestedTypes[0] == type ? dt.NestedTypes[1] : dt.NestedTypes[0]);
return dcGen;
}
static bool getMagicDC3(MethodDef method, ref int index, out int magic) {
var instrs = method.Body.Instructions;
for (int i = index; i < instrs.Count - 2; i++) {
var ldci4 = instrs[i];
if (!ldci4.IsLdcI4())
continue;
if (instrs[i + 1].OpCode.Code != Code.Xor)
continue;
if (instrs[i + 2].OpCode.Code != Code.Stfld)
continue;
index = i + 3;
magic = ldci4.GetLdcI4Value();
return true;
}
magic = 0;
return false;
}
DCGen2 getDCGen2(TypeDef type) {
var method = getMoveNext(type);
if (method == null)
return null;
simpleDeobfuscator.deobfuscate(method);
var dcGen = new DCGen2();
int index = 0;
if (!getMagicDC3(method, ref index, out dcGen.magic1))
return null;
return dcGen;
}
static MethodDef getMoveNext(TypeDef type) {
foreach (var m in type.Methods) {
if (!m.IsVirtual)
continue;
foreach (var mo in m.Overrides) {
if (mo.MethodDeclaration.FullName == "System.Boolean System.Collections.IEnumerator::MoveNext()")
return m;
}
}
foreach (var m in type.Methods) {
if (!m.IsVirtual)
continue;
if (m.Name != "MoveNext")
continue;
if (!DotNetUtils.isMethod(m, "System.Boolean", "()"))
continue;
return m;
}
return null;
}
}
}

77
de4dot.code/deobfuscators/Eazfuscator_NET/StringDecrypter.cs
View File

@ -47,6 +47,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
EfConstantsReader stringMethodConsts;
bool isV32OrLater;
int? validStringDecrypterValue;
Dynocode dynocode;
class StreamHelperType {
public TypeDef type;
@ -99,6 +100,10 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
}
}
public IEnumerable<TypeDef> DynocodeTypes {
get { return dynocode.Types; }
}
public MethodDef Method {
get { return stringMethod; }
}
@ -223,6 +228,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
}
bool findConstants(ISimpleDeobfuscator simpleDeobfuscator) {
dynocode = new Dynocode(simpleDeobfuscator);
simpleDeobfuscator.deobfuscate(stringMethod);
stringMethodConsts = new EfConstantsReader(stringMethod);
@ -630,6 +636,11 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
emu.push(new Int64Value((long)decrypterType.getMagic()));
break;
case Code.Newobj:
if (!emulateDynocode(emu, ref i))
goto default;
break;
default:
if (instr.OpCode.FlowControl != FlowControl.Next)
goto done;
@ -649,6 +660,72 @@ done: ;
return false;
}
bool emulateDynocode(InstructionEmulator emu, ref int index) {
var instrs = stringMethod.Body.Instructions;
var instr = instrs[index];
var ctor = instr.Operand as MethodDef;
if (ctor == null || ctor.MethodSig.GetParamCount() != 1 || ctor.MethodSig.Params[0].ElementType != ElementType.I4)
return false;
if (index + 4 >= instrs.Count)
return false;
var ldloc = instrs[index + 3];
if (!ldloc.IsLdloc() || instrs[index + 4].OpCode.Code != Code.Stfld)
return false;
var initValue = emu.getLocal(ldloc.GetLocal(stringMethod.Body.Variables)) as Int32Value;
if (initValue == null || !initValue.allBitsValid())
return false;
int leaveIndex = findLeave(instrs, index);
if (leaveIndex < 0)
return false;
var afterLoop = instrs[leaveIndex].Operand as Instruction;
if (afterLoop == null)
return false;
int newIndex = instrs.IndexOf(afterLoop);
var loopLocal = getDCLoopLocal(index, newIndex);
if (loopLocal == null)
return false;
var initValue2 = emu.getLocal(loopLocal) as Int32Value;
if (initValue2 == null || !initValue2.allBitsValid())
return false;
var dcGen = dynocode.getDynocodeGenerator(ctor.DeclaringType);
if (dcGen == null)
return false;
int loopLocalValue = initValue2.value;
foreach (var val in dcGen.getValues(initValue.value))
loopLocalValue ^= val;
emu.setLocal(loopLocal, new Int32Value(loopLocalValue));
emu.emulate(instr);
index = newIndex - 1;
return true;
}
Local getDCLoopLocal(int start, int end) {
var instrs = stringMethod.Body.Instructions;
for (int i = start; i < end - 1; i++) {
if (instrs[i].OpCode.Code != Code.Xor)
continue;
var stloc = instrs[i + 1];
if (!stloc.IsStloc())
continue;
return stloc.GetLocal(stringMethod.Body.Variables);
}
return null;
}
static int findLeave(IList<Instruction> instrs, int index) {
for (int i = index; i < instrs.Count; i++) {
if (instrs[i].OpCode.Code == Code.Leave_S || instrs[i].OpCode.Code == Code.Leave)
return i;
}
return -1;
}
static int findInitIntsIndex(MethodDef method, out bool initializedAll) {
initializedAll = false;