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Support Confuser 1.3 r55802 resource encrypter

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This commit is contained in:
de4dot 2012-07-31 10:00:46 +02:00
parent a2038f348e
commit b517755607
1 changed files with 76 additions and 10 deletions
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86
de4dot.code/deobfuscators/Confuser/ResourceDecrypter.cs
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@ -17,6 +17,7 @@
along with de4dot. If not, see <http://www.gnu.org/licenses/>.
*/
using System;
using System.Collections.Generic;
using System.IO;
using Mono.Cecil;
@ -32,6 +33,13 @@ namespace de4dot.code.deobfuscators.Confuser {
EmbeddedResource resource;
Dictionary<FieldDefinition, bool> fields = new Dictionary<FieldDefinition, bool>();
byte key0, key1;
ConfuserVersion version = ConfuserVersion.Unknown;
enum ConfuserVersion {
Unknown,
v13_r55802,
vXX,
}
public IEnumerable<FieldDefinition> Fields {
get { return fields.Keys; }
@ -67,22 +75,33 @@ namespace de4dot.code.deobfuscators.Confuser {
if (tmpHandler == null || tmpHandler.DeclaringType != method.DeclaringType)
return false;
simpleDeobfuscator.deobfuscate(tmpHandler, true);
if (addFields(findFields(tmpHandler, method.DeclaringType)) != 1)
return false;
var tmpResource = findResource(tmpHandler);
if (tmpResource == null)
return false;
if (!findKey0(tmpHandler, out key0))
return false;
if (!findKey1(tmpHandler, out key1))
return false;
simpleDeobfuscator.deobfuscate(tmpHandler, true);
ConfuserVersion tmpVersion = ConfuserVersion.Unknown;
if (DotNetUtils.callsMethod(tmpHandler, "System.Object System.AppDomain::GetData(System.String)")) {
tmpVersion = ConfuserVersion.v13_r55802;
if (!findKey0Key1_v13_r55802(tmpHandler, out key0, out key1))
return false;
}
else {
tmpVersion = ConfuserVersion.vXX;
if (addFields(findFields(tmpHandler, method.DeclaringType)) != 1)
return false;
if (!findKey0_vXX(tmpHandler, out key0))
return false;
if (!findKey1_vXX(tmpHandler, out key1))
return false;
}
handler = tmpHandler;
resource = tmpResource;
installMethod = method;
version = tmpVersion;
return true;
}
@ -146,7 +165,7 @@ namespace de4dot.code.deobfuscators.Confuser {
return DotNetUtils.getResource(module, DotNetUtils.getCodeStrings(method)) as EmbeddedResource;
}
static bool findKey0(MethodDefinition method, out byte key0) {
static bool findKey0_vXX(MethodDefinition method, out byte key0) {
var instrs = method.Body.Instructions;
for (int index = 0; index < instrs.Count; index++) {
index = ConfuserUtils.findCallMethod(instrs, index, Code.Callvirt, "System.Int32 System.IO.Stream::Read(System.Byte[],System.Int32,System.Int32)");
@ -175,7 +194,7 @@ namespace de4dot.code.deobfuscators.Confuser {
return false;
}
static bool findKey1(MethodDefinition method, out byte key1) {
static bool findKey1_vXX(MethodDefinition method, out byte key1) {
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count - 4; i++) {
int index = i;
@ -200,6 +219,33 @@ namespace de4dot.code.deobfuscators.Confuser {
return false;
}
static bool findKey0Key1_v13_r55802(MethodDefinition method, out byte key0, out byte key1) {
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count - 5; i++) {
if (!DotNetUtils.isLdcI4(instrs[i]))
continue;
if (instrs[i + 1].OpCode.Code != Code.Add)
continue;
if (instrs[i + 2].OpCode.Code != Code.Ldelem_U1)
continue;
var ldci4_1 = instrs[i + 3];
if (!DotNetUtils.isLdcI4(ldci4_1))
continue;
if (instrs[i + 4].OpCode.Code != Code.Xor)
continue;
var ldci4_2 = instrs[i + 5];
if (!DotNetUtils.isLdcI4(ldci4_2))
continue;
key0 = (byte)DotNetUtils.getLdcI4Value(ldci4_1);
key1 = (byte)DotNetUtils.getLdcI4Value(ldci4_2);
return true;
}
key0 = 0;
key1 = 0;
return false;
}
public EmbeddedResource mergeResources() {
if (resource == null)
return null;
@ -208,6 +254,26 @@ namespace de4dot.code.deobfuscators.Confuser {
}
byte[] decryptResource() {
switch (version) {
case ConfuserVersion.v13_r55802: return decrypt_v13_r55802();
case ConfuserVersion.vXX: return decrypt_vXX();
default: throw new ApplicationException("Unknown version");
}
}
byte[] decrypt_v13_r55802() {
var reader = new BinaryReader(new MemoryStream(DeobUtils.inflate(resource.GetResourceData(), true)));
var encypted = reader.ReadBytes(reader.ReadInt32());
if ((encypted.Length & 1) != 0)
throw new ApplicationException("Invalid resource data length");
var decrypted = new byte[encypted.Length / 2];
for (int i = 0; i < decrypted.Length; i++)
decrypted[i] = (byte)((encypted[i * 2 + 1] ^ key0) * key1 + (encypted[i * 2] ^ key0));
reader = new BinaryReader(new MemoryStream(DeobUtils.inflate(decrypted, true)));
return reader.ReadBytes(reader.ReadInt32());
}
byte[] decrypt_vXX() {
var encrypted = resource.GetResourceData();
byte k = key0;
for (int i = 0; i < encrypted.Length; i++) {