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Move detection of CV main type to its own class

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This commit is contained in:
de4dot 2012-02-08 15:40:11 +01:00
parent bb89ce2983
commit fa6b0d4054
6 changed files with 229 additions and 161 deletions
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1
de4dot.code/de4dot.code.csproj
View File

@ -80,6 +80,7 @@
<Compile Include="deobfuscators\CliSecure\StackFrameHelper.cs" />
<Compile Include="deobfuscators\CliSecure\StringDecrypter.cs" />
<Compile Include="deobfuscators\CodeVeil\AssemblyResolver.cs" />
<Compile Include="deobfuscators\CodeVeil\MainType.cs" />
<Compile Include="deobfuscators\CodeVeil\MethodsDecrypter.cs" />
<Compile Include="deobfuscators\CodeVeil\ObfuscatorVersion.cs" />
<Compile Include="deobfuscators\CodeVeil\StringDecrypter.cs" />

23
de4dot.code/deobfuscators/CodeVeil/Deobfuscator.cs
View File

@ -57,6 +57,7 @@ namespace de4dot.code.deobfuscators.CodeVeil {
string obfuscatorName = DeobfuscatorInfo.THE_NAME;
bool foundKillType = false;
MainType mainType;
MethodsDecrypter methodsDecrypter;
ProxyDelegateFinder proxyDelegateFinder;
StringDecrypter stringDecrypter;
@ -85,7 +86,8 @@ namespace de4dot.code.deobfuscators.CodeVeil {
protected override int detectInternal() {
int val = 0;
int sum = toInt32(methodsDecrypter.Detected) +
int sum = toInt32(mainType.Detected) +
toInt32(methodsDecrypter.Detected) +
toInt32(stringDecrypter.Detected) +
toInt32(proxyDelegateFinder.Detected);
if (sum > 0)
@ -98,11 +100,13 @@ namespace de4dot.code.deobfuscators.CodeVeil {
protected override void scanForObfuscator() {
findKillType();
proxyDelegateFinder = new ProxyDelegateFinder(module);
mainType = new MainType(module);
mainType.find();
proxyDelegateFinder = new ProxyDelegateFinder(module, mainType);
proxyDelegateFinder.findDelegateCreator();
methodsDecrypter = new MethodsDecrypter(module);
methodsDecrypter = new MethodsDecrypter(mainType);
methodsDecrypter.find();
stringDecrypter = new StringDecrypter(module);
stringDecrypter = new StringDecrypter(module, mainType);
stringDecrypter.find();
var version = detectVersion();
if (!string.IsNullOrEmpty(version))
@ -110,8 +114,8 @@ namespace de4dot.code.deobfuscators.CodeVeil {
}
string detectVersion() {
if (methodsDecrypter.Detected) {
switch (methodsDecrypter.Version) {
if (mainType.Detected) {
switch (mainType.Version) {
case ObfuscatorVersion.Unknown:
return null;
@ -160,9 +164,10 @@ namespace de4dot.code.deobfuscators.CodeVeil {
public override IDeobfuscator moduleReloaded(ModuleDefinition module) {
var newOne = new Deobfuscator(options);
newOne.setModule(module);
newOne.methodsDecrypter = new MethodsDecrypter(module, methodsDecrypter);
newOne.stringDecrypter = new StringDecrypter(module, stringDecrypter);
newOne.proxyDelegateFinder = new ProxyDelegateFinder(module, proxyDelegateFinder);
newOne.mainType = new MainType(module, mainType);
newOne.methodsDecrypter = new MethodsDecrypter(mainType, methodsDecrypter);
newOne.stringDecrypter = new StringDecrypter(module, newOne.mainType, stringDecrypter);
newOne.proxyDelegateFinder = new ProxyDelegateFinder(module, newOne.mainType, proxyDelegateFinder);
return newOne;
}

169
de4dot.code/deobfuscators/CodeVeil/MainType.cs Normal file
View File

@ -0,0 +1,169 @@
/*
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 Mono.Cecil;
using Mono.Cecil.Cil;
using Mono.Cecil.Metadata;
using de4dot.blocks;
namespace de4dot.code.deobfuscators.CodeVeil {
// Detects the type CV adds to the assembly that gets called from <Module>::.cctor.
class MainType {
ModuleDefinition module;
TypeDefinition theType;
MethodDefinition initMethod;
ObfuscatorVersion obfuscatorVersion = ObfuscatorVersion.Unknown;
List<int> rvas; // _stub and _executive
public bool Detected {
get { return theType != null; }
}
public ObfuscatorVersion Version {
get { return obfuscatorVersion; }
}
public TypeDefinition Type {
get { return theType; }
}
public MethodDefinition InitMethod {
get { return initMethod; }
}
public List<int> Rvas {
get { return rvas; }
}
public MainType(ModuleDefinition module) {
this.module = module;
}
public MainType(ModuleDefinition module, MainType oldOne) {
this.module = module;
this.theType = lookup(oldOne.theType, "Could not find main type");
this.initMethod = lookup(oldOne.initMethod, "Could not find main type init method");
this.obfuscatorVersion = oldOne.obfuscatorVersion;
this.rvas = oldOne.rvas;
}
T lookup<T>(T def, string errorMessage) where T : MemberReference {
return DeobUtils.lookup(module, def, errorMessage);
}
public void find() {
var cctor = DotNetUtils.getModuleTypeCctor(module);
if (cctor == null)
return;
var instrs = cctor.Body.Instructions;
for (int i = 0; i < instrs.Count - 2; i++) {
var ldci4_1 = instrs[i];
if (!DotNetUtils.isLdcI4(ldci4_1))
continue;
var ldci4_2 = instrs[i + 1];
if (!DotNetUtils.isLdcI4(ldci4_2))
continue;
var call = instrs[i + 2];
if (call.OpCode.Code != Code.Call)
continue;
var initMethodTmp = call.Operand as MethodDefinition;
ObfuscatorVersion obfuscatorVersionTmp;
if (!checkInitMethod(initMethodTmp, out obfuscatorVersionTmp))
continue;
if (!checkMethodsType(initMethodTmp.DeclaringType))
continue;
obfuscatorVersion = obfuscatorVersionTmp;
theType = initMethodTmp.DeclaringType;
initMethod = initMethodTmp;
break;
}
}
static string[] fieldTypesV5 = new string[] {
"System.Byte[]",
"System.Collections.Generic.List`1<System.Delegate>",
"System.Runtime.InteropServices.GCHandle",
};
bool checkInitMethod(MethodDefinition initMethod, out ObfuscatorVersion obfuscatorVersionTmp) {
obfuscatorVersionTmp = ObfuscatorVersion.Unknown;
if (initMethod == null)
return false;
if (initMethod.Body == null)
return false;
if (!initMethod.IsStatic)
return false;
if (!DotNetUtils.isMethod(initMethod, "System.Void", "(System.Boolean,System.Boolean)"))
return false;
if (hasCodeString(initMethod, "E_FullTrust")) {
if (DotNetUtils.getPInvokeMethod(initMethod.DeclaringType, "user32", "CallWindowProcW") != null)
obfuscatorVersionTmp = ObfuscatorVersion.V4_1;
else
obfuscatorVersionTmp = ObfuscatorVersion.V4_0;
}
else if (hasCodeString(initMethod, "Full Trust Required"))
obfuscatorVersionTmp = ObfuscatorVersion.V3;
else if (initMethod.DeclaringType.HasNestedTypes && new FieldTypes(initMethod.DeclaringType).all(fieldTypesV5))
obfuscatorVersionTmp = ObfuscatorVersion.V5_0;
else
return false;
return true;
}
static bool hasCodeString(MethodDefinition method, string str) {
foreach (var s in DotNetUtils.getCodeStrings(method)) {
if (s == str)
return true;
}
return false;
}
bool checkMethodsType(TypeDefinition type) {
var fields = getRvaFields(type);
if (fields.Count < 2) // RVAs for executive and stub are always present if encrypted methods
return true;
rvas = new List<int>(fields.Count);
foreach (var field in fields)
rvas.Add(field.RVA);
return true;
}
static List<FieldDefinition> getRvaFields(TypeDefinition type) {
var fields = new List<FieldDefinition>();
foreach (var field in type.Fields) {
if (field.FieldType.EType != ElementType.U1 && field.FieldType.EType != ElementType.U4)
continue;
if (field.RVA == 0)
continue;
fields.Add(field);
}
return fields;
}
}
}

137
de4dot.code/deobfuscators/CodeVeil/MethodsDecrypter.cs
View File

@ -29,33 +29,17 @@ using de4dot.code.PE;
namespace de4dot.code.deobfuscators.CodeVeil {
class MethodsDecrypter {
ModuleDefinition module;
TypeDefinition methodsType;
List<int> rvas; // _stub and _executive
MainType mainType;
IDecrypter decrypter;
public ObfuscatorVersion Version {
get { return decrypter == null ? ObfuscatorVersion.Unknown : decrypter.Version; }
}
interface IDecrypter {
ObfuscatorVersion Version { get; }
void initialize(byte[] methodsData);
bool decrypt(BinaryReader fileDataReader, DumpedMethod dm);
}
class Decrypter : IDecrypter {
ObfuscatorVersion obfuscatorVersion;
BinaryReader methodsDataReader;
public ObfuscatorVersion Version {
get { return obfuscatorVersion; }
}
public Decrypter(ObfuscatorVersion obfuscatorVersion) {
this.obfuscatorVersion = obfuscatorVersion;
}
public virtual void initialize(byte[] methodsData) {
methodsDataReader = new BinaryReader(new MemoryStream(methodsData));
}
@ -121,10 +105,6 @@ namespace de4dot.code.deobfuscators.CodeVeil {
class DecrypterV5 : Decrypter {
byte[] decryptKey;
public DecrypterV5()
: base(ObfuscatorVersion.V5_0) {
}
public override void initialize(byte[] methodsData) {
var data = DeobUtils.inflate(methodsData, true);
decryptKey = BitConverter.GetBytes(BitConverter.ToUInt32(data, 0));
@ -146,117 +126,42 @@ namespace de4dot.code.deobfuscators.CodeVeil {
}
public bool Detected {
get { return methodsType != null; }
get { return decrypter != null; }
}
public MethodsDecrypter(ModuleDefinition module) {
this.module = module;
public MethodsDecrypter(MainType mainType) {
this.mainType = mainType;
}
public MethodsDecrypter(ModuleDefinition module, MethodsDecrypter oldOne) {
this.module = module;
this.methodsType = lookup(oldOne.methodsType, "Could not find methods type");
}
T lookup<T>(T def, string errorMessage) where T : MemberReference {
return DeobUtils.lookup(module, def, errorMessage);
public MethodsDecrypter(MainType mainType, MethodsDecrypter oldOne) {
this.mainType = mainType;
}
public void find() {
var cctor = DotNetUtils.getModuleTypeCctor(module);
if (cctor == null)
if (!mainType.Detected)
return;
var instrs = cctor.Body.Instructions;
for (int i = 0; i < instrs.Count - 2; i++) {
var ldci4_1 = instrs[i];
if (!DotNetUtils.isLdcI4(ldci4_1))
continue;
var ldci4_2 = instrs[i + 1];
if (!DotNetUtils.isLdcI4(ldci4_2))
continue;
var call = instrs[i + 2];
if (call.OpCode.Code != Code.Call)
continue;
var initMethod = call.Operand as MethodDefinition;
if (!checkInitMethod(initMethod))
continue;
if (!checkMethodsType(initMethod.DeclaringType))
continue;
methodsType = initMethod.DeclaringType;
switch (mainType.Version) {
case ObfuscatorVersion.Unknown:
break;
}
}
static string[] fieldTypesV5 = new string[] {
"System.Byte[]",
"System.Collections.Generic.List`1<System.Delegate>",
"System.Runtime.InteropServices.GCHandle",
};
bool checkInitMethod(MethodDefinition initMethod) {
if (initMethod == null)
return false;
case ObfuscatorVersion.V3:
case ObfuscatorVersion.V4_0:
case ObfuscatorVersion.V4_1:
decrypter = new Decrypter();
break;
if (initMethod.Body == null)
return false;
if (!initMethod.IsStatic)
return false;
if (!DotNetUtils.isMethod(initMethod, "System.Void", "(System.Boolean,System.Boolean)"))
return false;
if (hasCodeString(initMethod, "E_FullTrust")) {
if (DotNetUtils.getPInvokeMethod(initMethod.DeclaringType, "user32", "CallWindowProcW") != null)
decrypter = new Decrypter(ObfuscatorVersion.V4_1);
else
decrypter = new Decrypter(ObfuscatorVersion.V4_0);
}
else if (hasCodeString(initMethod, "Full Trust Required"))
decrypter = new Decrypter(ObfuscatorVersion.V3);
else if (initMethod.DeclaringType.HasNestedTypes && new FieldTypes(initMethod.DeclaringType).all(fieldTypesV5))
case ObfuscatorVersion.V5_0:
decrypter = new DecrypterV5();
else
return false;
break;
return true;
}
static bool hasCodeString(MethodDefinition method, string str) {
foreach (var s in DotNetUtils.getCodeStrings(method)) {
if (s == str)
return true;
default:
throw new ApplicationException("Unknown version");
}
return false;
}
bool checkMethodsType(TypeDefinition type) {
var fields = getRvaFields(type);
if (fields.Count < 2)
return false;
rvas = new List<int>(fields.Count);
foreach (var field in fields)
rvas.Add(field.RVA);
return true;
}
static List<FieldDefinition> getRvaFields(TypeDefinition type) {
var fields = new List<FieldDefinition>();
foreach (var field in type.Fields) {
if (field.FieldType.EType != ElementType.U1 && field.FieldType.EType != ElementType.U4)
continue;
if (field.RVA == 0)
continue;
fields.Add(field);
}
return fields;
}
public bool decrypt(byte[] fileData, ref Dictionary<uint, DumpedMethod> dumpedMethods) {
if (methodsType == null)
if (decrypter == null)
return false;
var peImage = new PeImage(fileData);
@ -356,7 +261,7 @@ namespace de4dot.code.deobfuscators.CodeVeil {
return null;
int rva = BitConverter.ToInt32(fileData, offset + RVA_EXECUTIVE_OFFSET);
if (rvas.IndexOf(rva) < 0)
if (mainType.Rvas.IndexOf(rva) < 0)
continue;
int relOffs = BitConverter.ToInt32(fileData, offset + ENC_CODE_OFFSET);
@ -377,7 +282,7 @@ namespace de4dot.code.deobfuscators.CodeVeil {
int getStartOffset(PeImage peImage) {
int minOffset = int.MaxValue;
foreach (var rva in rvas) {
foreach (var rva in mainType.Rvas) {
int rvaOffs = (int)peImage.rvaToOffset((uint)rva);
if (rvaOffs < minOffset)
minOffset = rvaOffs;

33
de4dot.code/deobfuscators/CodeVeil/ProxyDelegateFinder.cs
View File

@ -26,11 +26,11 @@ using de4dot.blocks;
namespace de4dot.code.deobfuscators.CodeVeil {
class ProxyDelegateFinder : ProxyDelegateFinderBase {
MainType mainType;
Info info = new Info();
BinaryReader reader;
class Info {
public TypeDefinition mainType;
public TypeDefinition proxyType;
public MethodDefinition initMethod;
public FieldDefinition dataField;
@ -44,13 +44,14 @@ namespace de4dot.code.deobfuscators.CodeVeil {
}
}
public ProxyDelegateFinder(ModuleDefinition module)
public ProxyDelegateFinder(ModuleDefinition module, MainType mainType)
: base(module) {
this.mainType = mainType;
}
public ProxyDelegateFinder(ModuleDefinition module, ProxyDelegateFinder oldOne)
public ProxyDelegateFinder(ModuleDefinition module, MainType mainType, ProxyDelegateFinder oldOne)
: base(module, oldOne) {
info.mainType = lookup(oldOne.info.mainType, "Could not find mainType");
this.mainType = mainType;
info.proxyType = lookup(oldOne.info.proxyType, "Could not find proxyType");
info.initMethod = lookup(oldOne.info.initMethod, "Could not find initMethod");
info.dataField = lookup(oldOne.info.dataField, "Could not find dataField");
@ -97,22 +98,15 @@ namespace de4dot.code.deobfuscators.CodeVeil {
}
public void findDelegateCreator() {
var moduleCctor = DotNetUtils.getModuleTypeCctor(module);
if (moduleCctor == null)
if (!mainType.Detected)
return;
foreach (var call in DotNetUtils.getCalledMethods(module, moduleCctor)) {
if (!call.Item2.IsStatic)
continue;
if (!DotNetUtils.isMethod(call.Item2, "System.Void", "(System.Boolean,System.Boolean)"))
continue;
var infoTmp = new Info();
if (!initializeInfo(infoTmp, call.Item1))
continue;
info = infoTmp;
setDelegateCreatorMethod(info.initMethod);
var infoTmp = new Info();
if (!initializeInfo(infoTmp, mainType.Type))
return;
}
info = infoTmp;
setDelegateCreatorMethod(info.initMethod);
}
bool initializeInfo(Info infoTmp, TypeDefinition type) {
@ -123,7 +117,6 @@ namespace de4dot.code.deobfuscators.CodeVeil {
if (!initProxyType(infoTmp, cctor))
continue;
infoTmp.mainType = type;
return true;
}
@ -184,7 +177,9 @@ namespace de4dot.code.deobfuscators.CodeVeil {
}
protected override IEnumerable<TypeDefinition> getDelegateTypes() {
return info.mainType.NestedTypes;
if (!mainType.Detected)
return new List<TypeDefinition>();
return mainType.Type.NestedTypes;
}
public void initialize() {

27
de4dot.code/deobfuscators/CodeVeil/StringDecrypter.cs
View File

@ -26,6 +26,7 @@ using de4dot.blocks;
namespace de4dot.code.deobfuscators.CodeVeil {
class StringDecrypter {
ModuleDefinition module;
MainType mainType;
TypeDefinition decrypterType;
FieldDefinition stringDataField;
MethodDefinition initMethod;
@ -40,12 +41,14 @@ namespace de4dot.code.deobfuscators.CodeVeil {
get { return decrypterMethod; }
}
public StringDecrypter(ModuleDefinition module) {
public StringDecrypter(ModuleDefinition module, MainType mainType) {
this.module = module;
this.mainType = mainType;
}
public StringDecrypter(ModuleDefinition module, StringDecrypter oldOne) {
public StringDecrypter(ModuleDefinition module, MainType mainType, StringDecrypter oldOne) {
this.module = module;
this.mainType = mainType;
this.decrypterType = lookup(oldOne.decrypterType, "Could not find string decrypter type");
this.stringDataField = lookup(oldOne.stringDataField, "Could not find string data field");
this.initMethod = lookup(oldOne.initMethod, "Could not find string decrypter init method");
@ -95,21 +98,11 @@ namespace de4dot.code.deobfuscators.CodeVeil {
// The main decrypter type calls the string decrypter init method inside its init method
void find_V5(MethodDefinition method) {
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count; i++) {
var call = instrs[i];
if (call.OpCode.Code != Code.Call)
continue;
var mainTypeInitMethod = call.Operand as MethodDefinition;
if (mainTypeInitMethod == null || mainTypeInitMethod.Body == null || !mainTypeInitMethod.IsStatic)
continue;
if (!DotNetUtils.isMethod(mainTypeInitMethod, "System.Void", "(System.Boolean,System.Boolean)"))
continue;
foreach (var info in DotNetUtils.getCalledMethods(module, mainTypeInitMethod)) {
if (find(info.Item2))
return;
}
if (!mainType.Detected)
return;
foreach (var info in DotNetUtils.getCalledMethods(module, mainType.InitMethod)) {
if (find(info.Item2))
return;
}
}