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This commit is contained in:
de4dot 2012-12-02 16:20:25 +01:00
parent 938bdcd104
commit ca6812bca7
4 changed files with 332 additions and 107 deletions
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1
de4dot.code/de4dot.code.csproj
View File

@ -231,6 +231,7 @@
<Compile Include="deobfuscators\QuickLZ.cs" />
<Compile Include="deobfuscators\RandomNameChecker.cs" />
<Compile Include="deobfuscators\Rummage\Deobfuscator.cs" />
<Compile Include="deobfuscators\Rummage\RummageVersion.cs" />
<Compile Include="deobfuscators\Rummage\StringDecrypter.cs" />
<Compile Include="deobfuscators\Skater_NET\Deobfuscator.cs" />
<Compile Include="deobfuscators\Skater_NET\EnumClassFinder.cs" />

15
de4dot.code/deobfuscators/Rummage/Deobfuscator.cs
View File

@ -46,6 +46,7 @@ namespace de4dot.code.deobfuscators.Rummage {
}
class Deobfuscator : DeobfuscatorBase {
string obfuscatorName = DeobfuscatorInfo.THE_NAME;
StringDecrypter stringDecrypter;
internal class Options : OptionsBase {
@ -60,7 +61,7 @@ namespace de4dot.code.deobfuscators.Rummage {
}
public override string Name {
get { return TypeLong; }
get { return obfuscatorName; }
}
public Deobfuscator(Options options)
@ -80,6 +81,18 @@ namespace de4dot.code.deobfuscators.Rummage {
protected override void scanForObfuscator() {
stringDecrypter = new StringDecrypter(module);
stringDecrypter.find();
detectVersion();
}
void detectVersion() {
string version;
switch (stringDecrypter.Version) {
case RummageVersion.V1_1_445: version = "v1.1 - v2.0"; break;
case RummageVersion.V2_1_729: version = "v2.1 - v2.2"; break;
default: version = null; break;
}
if (version != null)
obfuscatorName += " " + version;
}
public override void deobfuscateBegin() {

26
de4dot.code/deobfuscators/Rummage/RummageVersion.cs Normal file
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@ -0,0 +1,26 @@
/*
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/>.
*/
namespace de4dot.code.deobfuscators.Rummage {
enum RummageVersion {
Unknown,
V1_1_445, // 1.1.445.2781 - 2.0.640.3707
V2_1_729, // 2.1.729.3909 - 2.2.750.3964
}
}

397
de4dot.code/deobfuscators/Rummage/StringDecrypter.cs
View File

@ -28,11 +28,275 @@ using de4dot.blocks;
namespace de4dot.code.deobfuscators.Rummage {
class StringDecrypter {
ModuleDefMD module;
MethodDef stringDecrypterMethod;
FieldDefAndDeclaringTypeDict<StringInfo> stringInfos = new FieldDefAndDeclaringTypeDict<StringInfo>();
int fileDispl;
uint[] key;
BinaryReader reader;
IDecrypter decrypter;
interface IDecrypter {
RummageVersion Version { get; }
MethodDef Method { get; }
void initialize();
string decrypt(int stringId);
}
abstract class DecrypterBaseV11 : IDecrypter {
RummageVersion version;
MethodDef decrypterMethod;
protected int fileDispl;
protected BinaryReader reader;
protected uint[] key;
public RummageVersion Version {
get { return version; }
}
public MethodDef Method {
get { return decrypterMethod; }
}
protected DecrypterBaseV11(RummageVersion version, MethodDef decrypterMethod, int fileDispl) {
this.version = version;
this.decrypterMethod = decrypterMethod;
this.fileDispl = fileDispl;
}
public void initialize() {
reader = new BinaryReader(new FileStream(decrypterMethod.DeclaringType.Module.Location, FileMode.Open, FileAccess.Read, FileShare.Read));
initializeImpl();
}
protected abstract void initializeImpl();
protected static MethodDef findDecrypterMethod(TypeDef type) {
MethodDef cctor = null, decrypterMethod = null;
foreach (var method in type.Methods) {
if (!method.IsStatic || method.Body == null)
return null;
if (method.Name == ".cctor")
cctor = method;
else if (DotNetUtils.isMethod(method, "System.String", "(System.Int32)"))
decrypterMethod = method;
else
return null;
}
if (cctor == null || decrypterMethod == null)
return null;
return decrypterMethod;
}
public abstract string decrypt(int stringId);
protected string decryptInternal(int stringId) {
uint v0 = reader.ReadUInt32();
uint v1 = reader.ReadUInt32();
DeobUtils.xteaDecrypt(ref v0, ref v1, key, 32);
int utf8Length = (int)v0;
var decrypted = new uint[(utf8Length + 11) / 8 * 2 - 1];
decrypted[0] = v1;
for (int i = 1; i + 1 < decrypted.Length; i += 2) {
v0 = reader.ReadUInt32();
v1 = reader.ReadUInt32();
DeobUtils.xteaDecrypt(ref v0, ref v1, key, 32);
decrypted[i] = v0;
decrypted[i + 1] = v1;
}
var utf8 = new byte[utf8Length];
Buffer.BlockCopy(decrypted, 0, utf8, 0, utf8.Length);
return Encoding.UTF8.GetString(utf8);
}
}
class DecrypterV11 : DecrypterBaseV11 {
DecrypterV11(MethodDef decrypterMethod, int fileDispl)
: base(RummageVersion.V1_1_445, decrypterMethod, fileDispl) {
}
public static DecrypterV11 create(MethodDef cctor) {
var method = checkType(cctor);
if (method == null)
return null;
int fileDispl;
if (!getDispl(method, out fileDispl))
return null;
return new DecrypterV11(method, fileDispl);
}
static readonly string[] requiredFields = new string[] {
"System.UInt32[]",
};
static readonly string[] requiredLocals = new string[] {
"System.Byte[]",
"System.Int32",
"System.IO.FileStream",
};
static MethodDef checkType(MethodDef cctor) {
var type = cctor.DeclaringType;
if (!new FieldTypes(type).exactly(requiredFields))
return null;
if (!new LocalTypes(cctor).all(requiredLocals))
return null;
return findDecrypterMethod(type);
}
static bool getDispl(MethodDef method, out int displ) {
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count - 2; i++) {
var mul = instrs[i];
if (mul.OpCode.Code != Code.Mul)
continue;
var ldci4 = instrs[i + 1];
if (!ldci4.IsLdcI4())
continue;
var sub = instrs[i + 2];
if (sub.OpCode.Code != Code.Sub)
continue;
displ = ldci4.GetLdcI4Value();
return true;
}
displ = 0;
return false;
}
protected override void initializeImpl() {
initKey();
}
void initKey() {
reader.BaseStream.Position = reader.BaseStream.Length - 48;
key = new uint[4];
for (int i = 0; i < key.Length; i++)
key[i] = reader.ReadUInt32();
}
public override string decrypt(int stringId) {
reader.BaseStream.Position = reader.BaseStream.Length + (stringId * 4 - fileDispl);
return decryptInternal(stringId);
}
}
class DecrypterV21 : DecrypterBaseV11 {
long baseOffs;
public DecrypterV21(MethodDef decrypterMethod, int fileDispl)
: base(RummageVersion.V2_1_729, decrypterMethod, fileDispl) {
}
public static DecrypterV21 create(MethodDef cctor) {
var method = checkType(cctor);
if (method == null)
return null;
int fileDispl;
if (!getDispl(method, out fileDispl))
return null;
return new DecrypterV21(method, fileDispl);
}
static readonly string[] requiredFields = new string[] {
"System.UInt32[]",
"System.Int64",
};
static readonly string[] requiredLocals = new string[] {
"System.Boolean",
"System.Byte[]",
"System.Int32",
"System.IO.FileStream",
};
static MethodDef checkType(MethodDef cctor) {
var type = cctor.DeclaringType;
if (!new FieldTypes(type).exactly(requiredFields))
return null;
if (!new LocalTypes(cctor).all(requiredLocals))
return null;
return findDecrypterMethod(type);
}
static bool getDispl(MethodDef method, out int displ) {
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count - 6; i++) {
var ldci4_1 = instrs[i];
if (!ldci4_1.IsLdcI4() || ldci4_1.GetLdcI4Value() != 4)
continue;
if (instrs[i + 1].OpCode.Code != Code.Mul)
continue;
if (instrs[i + 2].OpCode.Code != Code.Conv_I8)
continue;
if (instrs[i + 3].OpCode.Code != Code.Add)
continue;
var ldci4 = instrs[i + 4];
if (!ldci4.IsLdcI4())
continue;
if (instrs[i + 5].OpCode.Code != Code.Conv_I8)
continue;
if (instrs[i + 6].OpCode.Code != Code.Sub)
continue;
displ = ldci4.GetLdcI4Value();
return true;
}
displ = 0;
return false;
}
static readonly byte[] magic = new byte[32] {
0xC9, 0x76, 0xC3, 0x0D, 0xE2, 0x83, 0x72, 0xE4,
0xD5, 0xC7, 0x35, 0xF8, 0x86, 0xD0, 0x60, 0x69,
0xEE, 0xE1, 0x4C, 0x5E, 0x07, 0xA1, 0xC1, 0xFE,
0x61, 0xE3, 0xAA, 0xBC, 0xE4, 0xB1, 0xF0, 0x92,
};
protected override void initializeImpl() {
baseOffs = initializeBaseOffs();
initKey();
}
void initKey() {
reader.BaseStream.Position = baseOffs - 16;
key = new uint[4];
for (int i = 0; i < key.Length; i++)
key[i] = reader.ReadUInt32();
}
long initializeBaseOffs() {
byte[] buf = new byte[0x1000]; // Must be 4096 bytes
reader.BaseStream.Position = reader.BaseStream.Length - buf.Length;
while (true) {
if (reader.Read(buf, 0, buf.Length) != buf.Length)
throw new ApplicationException("Could not read");
for (int bi = buf.Length - 1; bi > magic.Length; ) {
int mi = magic.Length - 1;
if (buf[bi--] != magic[mi--] ||
buf[bi] != magic[mi--])
continue;
while (true) {
if (buf[--bi] != magic[mi--])
break;
if (mi == -1)
return reader.BaseStream.Position - buf.Length + bi;
}
}
reader.BaseStream.Position -= buf.Length * 2 - 0x20;
}
}
public override string decrypt(int stringId) {
reader.BaseStream.Position = baseOffs + stringId * 4 - fileDispl;
return decryptInternal(stringId);
}
}
class StringInfo {
public readonly FieldDef field;
@ -51,8 +315,12 @@ namespace de4dot.code.deobfuscators.Rummage {
}
}
public RummageVersion Version {
get { return decrypter == null ? RummageVersion.Unknown : decrypter.Version; }
}
public TypeDef Type {
get { return stringDecrypterMethod != null ? stringDecrypterMethod.DeclaringType : null; }
get { return decrypter != null ? decrypter.Method.DeclaringType : null; }
}
public IEnumerable<TypeDef> OtherTypes {
@ -65,7 +333,7 @@ namespace de4dot.code.deobfuscators.Rummage {
}
public bool Detected {
get { return stringDecrypterMethod != null; }
get { return decrypter != null; }
}
public StringDecrypter(ModuleDefMD module) {
@ -73,93 +341,30 @@ namespace de4dot.code.deobfuscators.Rummage {
}
public void find() {
foreach (var type in module.Types) {
var method = checkType(type);
if (method == null)
continue;
if (!getDispl(method, ref fileDispl))
foreach (var type in module.GetTypes()) {
var cctor = type.FindStaticConstructor();
if (cctor == null)
continue;
stringDecrypterMethod = method;
break;
decrypter = DecrypterV11.create(cctor);
if (decrypter != null)
break;
decrypter = DecrypterV21.create(cctor);
if (decrypter != null)
break;
}
}
static readonly string[] requiredFields = new string[] {
"System.UInt32[]",
};
static readonly string[] requiredLocals = new string[] {
"System.Byte[]",
"System.Int32",
"System.IO.FileStream",
};
static MethodDef checkType(TypeDef type) {
if (!new FieldTypes(type).exactly(requiredFields))
return null;
var cctor = type.FindStaticConstructor();
if (cctor == null)
return null;
if (!new LocalTypes(cctor).all(requiredLocals))
return null;
return checkMethods(type);
}
static MethodDef checkMethods(TypeDef type) {
MethodDef cctor = null, decrypterMethod = null;
foreach (var method in type.Methods) {
if (!method.IsStatic || method.Body == null)
return null;
if (method.Name == ".cctor")
cctor = method;
else if (DotNetUtils.isMethod(method, "System.String", "(System.Int32)"))
decrypterMethod = method;
else
return null;
}
if (cctor == null || decrypterMethod == null)
return null;
return decrypterMethod;
}
static bool getDispl(MethodDef method, ref int displ) {
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count - 2; i++) {
var mul = instrs[i];
if (mul.OpCode.Code != Code.Mul)
continue;
var ldci4 = instrs[i + 1];
if (!ldci4.IsLdcI4())
continue;
var sub = instrs[i + 2];
if (sub.OpCode.Code != Code.Sub)
continue;
displ = ldci4.GetLdcI4Value();
return true;
}
return false;
}
public void initialize() {
reader = new BinaryReader(new FileStream(module.Location, FileMode.Open, FileAccess.Read, FileShare.Read));
initKey();
if (decrypter == null)
return;
decrypter.initialize();
foreach (var type in module.Types)
initType(type);
}
void initKey() {
reader.BaseStream.Position = reader.BaseStream.Length - 48;
key = new uint[4];
for (int i = 0; i < key.Length; i++)
key[i] = reader.ReadUInt32();
}
void initType(TypeDef type) {
var cctor = type.FindStaticConstructor();
if (cctor == null)
@ -185,7 +390,7 @@ namespace de4dot.code.deobfuscators.Rummage {
if (call.OpCode.Code != Code.Call)
continue;
var calledMethod = call.Operand as IMethod;
if (!MethodEqualityComparer.CompareDeclaringTypes.Equals(stringDecrypterMethod, calledMethod))
if (!MethodEqualityComparer.CompareDeclaringTypes.Equals(decrypter.Method, calledMethod))
continue;
var stsfld = instrs[i + 2];
@ -202,6 +407,8 @@ namespace de4dot.code.deobfuscators.Rummage {
}
public void deobfuscate(Blocks blocks) {
if (decrypter == null)
return;
foreach (var block in blocks.MethodBlocks.getAllBlocks()) {
var instrs = block.Instructions;
for (int i = 0; i < instrs.Count; i++) {
@ -226,31 +433,9 @@ namespace de4dot.code.deobfuscators.Rummage {
string decrypt(StringInfo info) {
if (info.decrypted == null)
info.decrypted = decrypt(info.stringId);
info.decrypted = decrypter.decrypt(info.stringId);
return info.decrypted;
}
string decrypt(int stringId) {
reader.BaseStream.Position = reader.BaseStream.Length + (stringId * 4 - fileDispl);
uint v0 = reader.ReadUInt32();
uint v1 = reader.ReadUInt32();
DeobUtils.xteaDecrypt(ref v0, ref v1, key, 32);
int utf8Length = (int)v0;
var decrypted = new uint[(utf8Length + 11) / 8 * 2 - 1];
decrypted[0] = v1;
for (int i = 1; i + 1 < decrypted.Length; i += 2) {
v0 = reader.ReadUInt32();
v1 = reader.ReadUInt32();
DeobUtils.xteaDecrypt(ref v0, ref v1, key, 32);
decrypted[i] = v0;
decrypted[i + 1] = v1;
}
var utf8 = new byte[utf8Length];
Buffer.BlockCopy(decrypted, 0, utf8, 0, utf8.Length);
return Encoding.UTF8.GetString(utf8);
}
}
}