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Support Confuser 1.4 r58564 methods encrypter

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This commit is contained in:
de4dot 2012-07-31 17:17:16 +02:00
parent 17495e986f
commit 2a96ec9958
2 changed files with 78 additions and 8 deletions
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47
de4dot.code/deobfuscators/Confuser/MemoryMethodsDecrypter.cs
View File

@ -33,6 +33,7 @@ namespace de4dot.code.deobfuscators.Confuser {
Unknown,
v14_r57884,
v14_r58004,
v14_r58564,
vXX,
}
@ -49,7 +50,8 @@ namespace de4dot.code.deobfuscators.Confuser {
return false;
if (type.Methods.Count != 3)
return false;
if (DotNetUtils.getPInvokeMethod(type, "kernel32", "VirtualProtect") == null)
var virtProtect = DotNetUtils.getPInvokeMethod(type, "kernel32", "VirtualProtect");
if (virtProtect == null)
return false;
if (!DotNetUtils.hasString(initMethod, "Broken file"))
return false;
@ -59,6 +61,8 @@ namespace de4dot.code.deobfuscators.Confuser {
if (!DotNetUtils.hasString(initMethod, "Module error"))
version = ConfuserVersion.v14_r57884;
else if (virtProtect.IsPrivate)
version = ConfuserVersion.v14_r58564;
else if (DotNetUtils.callsMethod(initMethod, "System.Void System.IO.FileStream::.ctor(System.String,System.IO.FileMode,System.IO.FileAccess,System.IO.FileShare)"))
version = ConfuserVersion.v14_r58004;
else
@ -76,6 +80,11 @@ namespace de4dot.code.deobfuscators.Confuser {
case ConfuserVersion.v14_r58004:
break;
case ConfuserVersion.v14_r58564:
if (!initializeKeys_v14_r58564())
throw new ApplicationException("Could not find all decryption keys");
break;
case ConfuserVersion.vXX:
if (!initializeKeys_vXX())
throw new ApplicationException("Could not find all decryption keys");
@ -86,6 +95,26 @@ namespace de4dot.code.deobfuscators.Confuser {
}
}
bool initializeKeys_v14_r58564() {
simpleDeobfuscator.deobfuscate(initMethod);
if (!findLKey0(initMethod, out lkey0))
return false;
if (!findKey0_v14_r58564(initMethod, out key0))
return false;
if (!findKey2Key3(initMethod, out key2, out key3))
return false;
if (!findKey4(initMethod, out key4))
return false;
if (!findKey5(initMethod, out key5))
return false;
simpleDeobfuscator.deobfuscate(decryptMethod);
if (!findKey6(decryptMethod, out key6))
return false;
return true;
}
bool initializeKeys_vXX() {
simpleDeobfuscator.deobfuscate(initMethod);
if (!findLKey0(initMethod, out lkey0))
@ -186,6 +215,7 @@ namespace de4dot.code.deobfuscators.Confuser {
switch (version) {
case ConfuserVersion.v14_r57884: return decrypt_v14_r57884(peImage, fileData, ref dumpedMethods);
case ConfuserVersion.v14_r58004: return decrypt_v14_r58004(peImage, fileData, ref dumpedMethods);
case ConfuserVersion.v14_r58564: return decrypt_v14_r58004(peImage, fileData, ref dumpedMethods);
case ConfuserVersion.vXX: return decrypt_vXX(peImage, fileData, ref dumpedMethods);
default: throw new ApplicationException("Unknown version");
}
@ -212,7 +242,7 @@ namespace de4dot.code.deobfuscators.Confuser {
byte[] decryptMethodsData_v14_r57884(PeImage peImage) {
var reader = peImage.Reader;
reader.BaseStream.Position = 0;
var md5SumData = reader.ReadBytes((int)peImage.OptionalHeader.checkSum);
var md5SumData = reader.ReadBytes((int)peImage.OptionalHeader.checkSum ^ (int)key0);
int csOffs = (int)peImage.OptionalHeader.Offset + 0x40;
md5SumData[csOffs] = 0;
@ -220,11 +250,11 @@ namespace de4dot.code.deobfuscators.Confuser {
md5SumData[csOffs + 2] = 0;
md5SumData[csOffs + 3] = 0;
var md5Sum = DeobUtils.md5Sum(md5SumData);
ulong checkSum = reader.ReadUInt64();
ulong checkSum = reader.ReadUInt64() ^ lkey0;
if (checkSum != calcChecksum(md5SumData))
throw new ApplicationException("Invalid checksum. File has been modified.");
var iv = reader.ReadBytes(reader.ReadInt32());
var encrypted = reader.ReadBytes(reader.ReadInt32());
var iv = reader.ReadBytes(reader.ReadInt32() ^ (int)key2);
var encrypted = reader.ReadBytes(reader.ReadInt32() ^ (int)key3);
var decrypted = decrypt(encrypted, iv, md5SumData);
if (BitConverter.ToInt16(decrypted, 0) != 0x6FD6)
throw new ApplicationException("Invalid magic");
@ -233,16 +263,19 @@ namespace de4dot.code.deobfuscators.Confuser {
bool decrypt_v14_r58004(PeImage peImage, byte[] fileData, ref DumpedMethods dumpedMethods) {
methodsData = decryptMethodsData_v14_r57884(peImage);
return decryptImage_v14_r58004(peImage, fileData, ref dumpedMethods);
}
bool decryptImage_v14_r58004(PeImage peImage, byte[] fileData, ref DumpedMethods dumpedMethods) {
var reader = new BinaryReader(new MemoryStream(methodsData));
reader.ReadInt16(); // sig
var writer = new BinaryWriter(new MemoryStream(fileData));
int numInfos = reader.ReadInt32();
for (int i = 0; i < numInfos; i++) {
uint offs = reader.ReadUInt32();
uint offs = reader.ReadUInt32() ^ key4;
if (offs == 0)
continue;
uint rva = reader.ReadUInt32();
uint rva = reader.ReadUInt32() ^ key4;
if (peImage.rvaToOffset(rva) != offs)
throw new ApplicationException("Invalid offs & rva");
writer.BaseStream.Position = peImage.rvaToOffset(rva);

39
de4dot.code/deobfuscators/Confuser/MethodsDecrypterBase.cs
View File

@ -74,8 +74,14 @@ namespace de4dot.code.deobfuscators.Confuser {
if (instr.OpCode.Code != Code.Call)
continue;
var calledMethod = instr.Operand as MethodDefinition;
if (calledMethod == null || calledMethod.Body == null)
try {
// If the body is encrypted, this could throw
if (calledMethod == null || calledMethod.Body == null)
continue;
}
catch {
continue;
}
if (!DotNetUtils.isMethod(calledMethod, "System.Void", "()"))
continue;
if (!checkType(calledMethod.DeclaringType, calledMethod))
@ -152,6 +158,37 @@ namespace de4dot.code.deobfuscators.Confuser {
return false;
}
protected static bool findKey0_v14_r58564(MethodDefinition method, out uint key) {
var instrs = method.Body.Instructions;
for (int i = 0; i + 5 < instrs.Count; i++) {
i = ConfuserUtils.findCallMethod(instrs, i, Code.Callvirt, "System.Int32 System.IO.BinaryReader::ReadInt32()");
if (i < 0)
break;
int index = i + 1;
var ldci4_1 = instrs[index++];
if (!DotNetUtils.isLdcI4(ldci4_1))
continue;
if (instrs[index++].OpCode.Code != Code.Xor)
continue;
if (!DotNetUtils.isStloc(instrs[index++]))
continue;
if (!DotNetUtils.isLdloc(instrs[index++]))
continue;
var ldci4_2 = instrs[index++];
if (!DotNetUtils.isLdcI4(ldci4_2))
continue;
if (DotNetUtils.getLdcI4Value(ldci4_2) != 0)
continue;
key = (uint)DotNetUtils.getLdcI4Value(ldci4_1);
return true;
}
key = 0;
return false;
}
protected static bool findKey1(MethodDefinition method, out uint key) {
var instrs = method.Body.Instructions;
for (int index = 0; index < instrs.Count; index++) {