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Support EF obfuscated SL assemblies

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This commit is contained in:
de4dot 2012-03-16 23:22:24 +01:00
parent d9aec67fcb
commit 9ecc5a313f
5 changed files with 143 additions and 29 deletions
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14
de4dot.code/deobfuscators/DeobUtils.cs
View File

@ -190,15 +190,21 @@ namespace de4dot.code.deobfuscators {
}
public static bool hasInteger(MethodDefinition method, int value) {
return indexOfLdci4Instruction(method, value) >= 0;
}
public static int indexOfLdci4Instruction(MethodDefinition method, int value) {
if (method == null || method.Body == null)
return false;
foreach (var instr in method.Body.Instructions) {
return -1;
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count; i++) {
var instr = instrs[i];
if (!DotNetUtils.isLdcI4(instr))
continue;
if (DotNetUtils.getLdcI4Value(instr) == value)
return true;
return i;
}
return false;
return -1;
}
}
}

71
de4dot.code/deobfuscators/Eazfuscator_NET/AssemblyResolver.cs
View File

@ -36,6 +36,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
MethodDefinition decryptMethod;
TypeDefinition otherType;
List<AssemblyInfo> assemblyInfos = new List<AssemblyInfo>();
FrameworkType frameworkType;
byte[] decryptKey;
public class AssemblyInfo {
@ -76,6 +77,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
public AssemblyResolver(ModuleDefinition module, DecrypterType decrypterType) {
this.module = module;
this.frameworkType = DotNetUtils.getFrameworkType(module);
this.decrypterType = decrypterType;
}
@ -90,20 +92,65 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
foreach (var instr in method.Body.Instructions) {
if (instr.OpCode.Code != Code.Call)
continue;
if (!checkInitMethod(instr.Operand as MethodDefinition))
continue;
var calledMethod = instr.Operand as MethodDefinition;
if (calledMethod == null || !calledMethod.IsStatic || calledMethod.Body == null)
return false;
if (!DotNetUtils.isMethod(calledMethod, "System.Void", "()"))
return false;
if (frameworkType == FrameworkType.Silverlight) {
if (!checkInitMethodSilverlight(calledMethod))
continue;
}
else {
if (!checkInitMethod(calledMethod))
continue;
}
decryptMethod = getDecryptMethod();
updateDecrypterType();
return true;
}
return false;
}
bool checkInitMethodSilverlight(MethodDefinition method) {
var type = method.DeclaringType;
if (type.NestedTypes.Count != 2)
return false;
var resolveHandler = getResolveMethodSilverlight(method);
if (resolveHandler == null)
return false;
initMethod = method;
resolverType = type;
handlerMethod = resolveHandler;
return true;
}
static MethodDefinition getResolveMethodSilverlight(MethodDefinition initMethod) {
foreach (var instr in initMethod.Body.Instructions) {
if (instr.OpCode.Code != Code.Call)
continue;
var calledMethod = instr.Operand as MethodDefinition;
if (calledMethod == null)
continue;
if (!DotNetUtils.isMethod(calledMethod, "System.Void", "()"))
continue;
if (!DeobUtils.hasInteger(calledMethod, ',') ||
!DeobUtils.hasInteger(calledMethod, '|'))
continue;
return calledMethod;
}
return null;
}
bool checkInitMethod(MethodDefinition method) {
if (method == null || !method.IsStatic || method.Body == null)
return false;
if (!DotNetUtils.isMethod(method, "System.Void", "()"))
return false;
var type = method.DeclaringType;
if (type.NestedTypes.Count != 3)
return false;
@ -120,8 +167,6 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
initMethod = method;
resolverType = type;
handlerMethod = resolveHandler;
decryptMethod = getDecryptMethod();
updateDecrypterType();
return true;
}
@ -239,8 +284,9 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
}
bool createAssemblyInfos() {
int numElements = DeobUtils.hasInteger(handlerMethod, 3) ? 3 : 2;
foreach (var s in DotNetUtils.getCodeStrings(handlerMethod)) {
var infos = createAssemblyInfos(s);
var infos = createAssemblyInfos(s, numElements);
if (infos == null)
continue;
@ -251,17 +297,16 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
return false;
}
List<AssemblyInfo> createAssemblyInfos(string s) {
List<AssemblyInfo> createAssemblyInfos(string s, int numElements) {
try {
return tryCreateAssemblyInfos(s);
return tryCreateAssemblyInfos(s, numElements);
}
catch (FormatException) {
return null; // Convert.FromBase64String() failed
}
}
List<AssemblyInfo> tryCreateAssemblyInfos(string s) {
int numElements = decrypterType.Detected ? 3 : 2;
List<AssemblyInfo> tryCreateAssemblyInfos(string s, int numElements) {
var ary = s.Split(',');
if (ary.Length == 0 || ary.Length % numElements != 0)
return null;

22
de4dot.code/deobfuscators/Eazfuscator_NET/EfUtils.cs
View File

@ -24,6 +24,28 @@ using de4dot.blocks;
namespace de4dot.code.deobfuscators.Eazfuscator_NET {
static class EfUtils {
public static int indexOfPreviousLdci4Instruction(MethodDefinition method, int index) {
var instrs = method.Body.Instructions;
for (int i = index; i >= 0; i--) {
var instr = instrs[i];
if (DotNetUtils.isLdcI4(instr))
return i;
}
return -1;
}
public static int indexOfNextLdci4Instruction(MethodDefinition method, int index) {
if (index < 0)
return -1;
var instrs = method.Body.Instructions;
for (int i = index; i < instrs.Count; i++) {
var instr = instrs[i];
if (DotNetUtils.isLdcI4(instr))
return i;
}
return -1;
}
public static bool getNextInt32(MethodDefinition method, ref int index, out int val) {
for (; index < method.Body.Instructions.Count; index++) {
var instr = method.Body.Instructions[index];

46
de4dot.code/deobfuscators/Eazfuscator_NET/StringDecrypter.cs
View File

@ -23,6 +23,7 @@ using System.IO;
using System.Text;
using Mono.Cecil;
using Mono.Cecil.Cil;
using Mono.Cecil.Metadata;
using de4dot.blocks;
namespace de4dot.code.deobfuscators.Eazfuscator_NET {
@ -43,6 +44,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
BinaryReader reader;
DecrypterType decrypterType;
StreamHelperType streamHelperType;
bool isV32OrLater;
class StreamHelperType {
public TypeDefinition type;
@ -104,6 +106,15 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
this.decrypterType = decrypterType;
}
static bool checkIfV32OrLater(TypeDefinition type) {
int numInts = 0;
foreach (var field in type.Fields) {
if (field.FieldType.EType == ElementType.I4)
numInts++;
}
return numInts >= 2;
}
public void find() {
foreach (var type in module.Types) {
if (!checkType(type))
@ -115,6 +126,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
stringType = type;
stringMethod = method;
isV32OrLater = checkIfV32OrLater(stringType);
return;
}
}
@ -229,7 +241,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
if (dataDecrypterType == null)
return false;
if (decrypterType.Detected) {
if (isV32OrLater) {
bool initializedAll;
if (!findInts(stringMethod, out initializedAll))
return false;
@ -241,7 +253,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
return false;
}
if (!decrypterType.initialize())
if (decrypterType.Detected && !decrypterType.initialize())
return false;
}
@ -252,7 +264,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
}
void initializeFlags() {
if (!decrypterType.Detected || !DeobUtils.hasInteger(stringMethod, 0xFFFFFFF)) {
if (!isV32OrLater || !DeobUtils.hasInteger(stringMethod, 0xFFFFFFF)) {
// <= 3.3.134
rldFlag = 0x40000000;
bytesFlag = 0x80000000;
@ -305,8 +317,9 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
else
keyLen = reader.ReadInt16() ^ s2;
magic1 = i1 ^ i2;
if (decrypterType.Detected)
magic1 = (int)decrypterType.getMagic() ^ i1 ^ i2;
magic1 ^= (int)decrypterType.getMagic();
}
public string decrypt(int val) {
@ -316,7 +329,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
byte[] tmpKey;
if (theKey == null) {
tmpKey = reader.ReadBytes(keyLen == -1 ? (short)(reader.ReadInt16() ^ s3 ^ offset) : keyLen);
if (decrypterType.Detected) {
if (isV32OrLater) {
for (int i = 0; i < tmpKey.Length; i++)
tmpKey[i] ^= (byte)(magic1 >> ((i & 3) << 3));
}
@ -484,9 +497,30 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
return true;
}
// 3.2 (Silverlight)
if (findIntsSilverlight(method, ref initializedAll))
return true;
return false;
}
bool findIntsSilverlight(MethodDefinition method, ref bool initializedAll) {
int index = DeobUtils.indexOfLdci4Instruction(method, 268435314);
if (index < 0)
return false;
index--;
index = EfUtils.indexOfPreviousLdci4Instruction(method, index);
if (index < 0)
return false;
i1 = 0;
if (!EfUtils.getNextInt32(method, ref index, out i2))
return false;
initializedAll = method.Body.Instructions[index].OpCode.Code == Code.Stsfld;
return true;
}
bool findIntsCctor(MethodDefinition cctor) {
int index = 0;
if (!findCallGetFrame(cctor, ref index))
@ -516,7 +550,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
}
bool findInt3(MethodDefinition method) {
if (!decrypterType.Detected)
if (!isV32OrLater)
return findInt3Old(method);
return findInt3New(method);
}

19
de4dot.code/deobfuscators/Eazfuscator_NET/VersionDetector.cs
View File

@ -49,6 +49,7 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
return null;
bool hasConstantM2 = DeobUtils.hasInteger(decryptStringMethod, -2);
var frameworkType = DotNetUtils.getFrameworkType(decryptStringType.Module);
/////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////
@ -345,7 +346,8 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
!decryptStringMethod.IsSynchronized &&
decryptStringMethod.Body.MaxStackSize >= 1 &&
decryptStringMethod.Body.MaxStackSize <= 8 &&
decryptStringMethod.Body.ExceptionHandlers.Count == 2 &&
(decryptStringMethod.Body.ExceptionHandlers.Count == 2 ||
(frameworkType == FrameworkType.Silverlight && decryptStringMethod.Body.ExceptionHandlers.Count == 1)) &&
new LocalTypes(decryptStringMethod).exactly(locals29) &&
checkTypeFields(fields29)) {
return "2.9";
@ -395,7 +397,8 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
!decryptStringMethod.IsSynchronized &&
decryptStringMethod.Body.MaxStackSize >= 1 &&
decryptStringMethod.Body.MaxStackSize <= 8 &&
decryptStringMethod.Body.ExceptionHandlers.Count == 2 &&
(decryptStringMethod.Body.ExceptionHandlers.Count == 2 ||
(frameworkType == FrameworkType.Silverlight && decryptStringMethod.Body.ExceptionHandlers.Count == 1)) &&
new LocalTypes(decryptStringMethod).exactly(locals30) &&
checkTypeFields(fields30)) {
return "3.0";
@ -445,7 +448,8 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
!decryptStringMethod.IsSynchronized &&
decryptStringMethod.Body.MaxStackSize >= 1 &&
decryptStringMethod.Body.MaxStackSize <= 8 &&
decryptStringMethod.Body.ExceptionHandlers.Count == 2 &&
(decryptStringMethod.Body.ExceptionHandlers.Count == 2 ||
(frameworkType == FrameworkType.Silverlight && decryptStringMethod.Body.ExceptionHandlers.Count == 1)) &&
new LocalTypes(decryptStringMethod).exactly(locals31) &&
checkTypeFields(fields31)) {
return "3.1";
@ -497,7 +501,8 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
!decryptStringMethod.IsSynchronized &&
decryptStringMethod.Body.MaxStackSize >= 1 &&
decryptStringMethod.Body.MaxStackSize <= 8 &&
decryptStringMethod.Body.ExceptionHandlers.Count == 2 &&
(decryptStringMethod.Body.ExceptionHandlers.Count == 2 ||
(frameworkType == FrameworkType.Silverlight && decryptStringMethod.Body.ExceptionHandlers.Count == 1)) &&
new LocalTypes(decryptStringMethod).exactly(locals32) &&
checkTypeFields(fields32)) {
return "3.2";
@ -552,7 +557,8 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
!decryptStringMethod.IsSynchronized &&
decryptStringMethod.Body.MaxStackSize >= 1 &&
decryptStringMethod.Body.MaxStackSize <= 8 &&
decryptStringMethod.Body.ExceptionHandlers.Count == 2 &&
(decryptStringMethod.Body.ExceptionHandlers.Count == 2 ||
(frameworkType == FrameworkType.Silverlight && decryptStringMethod.Body.ExceptionHandlers.Count == 1)) &&
new LocalTypes(decryptStringMethod).exactly(locals33) &&
checkTypeFields(fields33)) {
return "3.3.29 - 3.3.57 (BETA)";
@ -608,7 +614,8 @@ namespace de4dot.code.deobfuscators.Eazfuscator_NET {
!decryptStringMethod.IsSynchronized &&
decryptStringMethod.Body.MaxStackSize >= 1 &&
decryptStringMethod.Body.MaxStackSize <= 8 &&
decryptStringMethod.Body.ExceptionHandlers.Count == 2 &&
(decryptStringMethod.Body.ExceptionHandlers.Count == 2 ||
(frameworkType == FrameworkType.Silverlight && decryptStringMethod.Body.ExceptionHandlers.Count == 1)) &&
new LocalTypes(decryptStringMethod).exactly(locals33) &&
checkTypeFields(fields33)) {
return "3.3";