Detect Confuser 1.4 r58802 proxy methods creator
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@ -46,6 +46,7 @@ namespace de4dot.code.deobfuscators.Confuser {
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v13_r55346,
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v13_r55604,
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v14_r58564,
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v14_r58802,
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v14_r58857,
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v17_r73740_normal,
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v17_r73740_native,
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@ -206,6 +207,7 @@ namespace de4dot.code.deobfuscators.Confuser {
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case ConfuserVersion.v13_r55346:
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case ConfuserVersion.v13_r55604:
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case ConfuserVersion.v14_r58564:
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case ConfuserVersion.v14_r58802:
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getCallInfo_v10_r48717(info, creatorInfo, out calledMethod, out callOpcode);
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break;
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@ -265,18 +267,22 @@ namespace de4dot.code.deobfuscators.Confuser {
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}
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void getCallInfo_v10_r48717(DelegateInitInfo info, ProxyCreatorInfo creatorInfo, out MethodReference calledMethod, out OpCode callOpcode) {
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bool? isNew = isNewFieldNameEncoding(info);
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if (isNew == null) {
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bool isNew = creatorInfo.version == ConfuserVersion.v14_r58802;
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int offs = creatorInfo.proxyCreatorType == ProxyCreatorType.CallOrCallvirt ? 2 : 1;
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if (isNew)
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offs--;
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int callvirtOffs = isNew ? 0 : 1;
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// This is an obfuscator bug. Field names are stored in the #Strings heap,
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// and strings in that heap are UTF8 zero terminated strings, but Confuser
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// can generate names with zeros in them. This was fixed in 1.4 58857.
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if (offs + 2 > info.field.Name.Length) {
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calledMethod = null;
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callOpcode = OpCodes.Call;
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return;
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}
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int offs = creatorInfo.proxyCreatorType == ProxyCreatorType.CallOrCallvirt ? 2 : 1;
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if (isNew.Value)
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offs--;
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int callvirtOffs = isNew.Value ? 0 : 1;
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uint token = BitConverter.ToUInt32(Encoding.Unicode.GetBytes(info.field.Name.ToCharArray(), offs, 2), 0) ^ creatorInfo.magic;
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uint table = token >> 24;
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if (table != 0 && table != 6 && table != 0x0A && table != 0x2B)
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@ -284,7 +290,7 @@ namespace de4dot.code.deobfuscators.Confuser {
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// 1.3 r55346 now correctly uses method reference tokens and finally fixed the old
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// bug of using methoddef tokens to reference external methods.
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if (isNew.Value || info.field.Name[0] == (char)1 || table != 0x06)
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if (isNew || info.field.Name[0] == (char)1 || table != 0x06)
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calledMethod = (MethodReference)module.LookupToken((int)token);
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else {
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var asmRef = module.AssemblyReferences[info.field.Name[0] - 2];
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@ -297,35 +303,6 @@ namespace de4dot.code.deobfuscators.Confuser {
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callOpcode = getCallOpCode(creatorInfo, isCallvirt);
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}
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// Returns true if Confuser 1.4 r58802 or later
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bool? isNewFieldNameEncoding(DelegateInitInfo info) {
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var creatorInfo = methodToInfo.find(info.creatorMethod);
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int oldLen, newLen;
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switch (creatorInfo.proxyCreatorType) {
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case ProxyCreatorType.Newobj:
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oldLen = 3;
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newLen = 2;
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break;
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case ProxyCreatorType.CallOrCallvirt:
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oldLen = 4;
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newLen = 3;
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break;
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default: throw new ApplicationException("Invalid proxy creator type");
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}
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if (info.field.Name.Length == oldLen)
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return false;
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if (info.field.Name.Length != newLen) {
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// This is an obfuscator bug. Field names are stored in the #Strings heap,
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// and strings in that heap are UTF8 zero terminated strings, but Confuser
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// can generate names with zeros in them. This was fixed in 1.4 58857.
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return null;
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}
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return true;
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}
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void getCallInfo_v14_r58857(DelegateInitInfo info, ProxyCreatorInfo creatorInfo, out MethodReference calledMethod, out OpCode callOpcode) {
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int offs = creatorInfo.proxyCreatorType == ProxyCreatorType.CallOrCallvirt ? 1 : 0;
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var nameInfo = decryptFieldName(info.field.Name);
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@ -501,8 +478,12 @@ namespace de4dot.code.deobfuscators.Confuser {
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MethodDefinition nativeMethod = null;
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uint magic;
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if (findMagic_v14_r58564(method, out magic)) {
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if (!DotNetUtils.callsMethod(method, "System.Byte[] System.Convert::FromBase64String(System.String)"))
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theVersion = ConfuserVersion.v14_r58564;
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if (!DotNetUtils.callsMethod(method, "System.Byte[] System.Convert::FromBase64String(System.String)")) {
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if (!isMethodCreator_v14_r58802(method, proxyType))
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theVersion = ConfuserVersion.v14_r58564;
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else
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theVersion = ConfuserVersion.v14_r58802;
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}
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else
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theVersion = ConfuserVersion.v14_r58857;
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}
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@ -559,6 +540,48 @@ namespace de4dot.code.deobfuscators.Confuser {
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}
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}
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static bool isMethodCreator_v14_r58802(MethodDefinition method, ProxyCreatorType proxyType) {
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int index = getFieldNameIndex(method);
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if (index < 0)
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throw new ApplicationException("Could not find field name index");
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switch (proxyType) {
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case ProxyCreatorType.Newobj:
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if (index == 1)
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return false;
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if (index == 0)
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return true;
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break;
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case ProxyCreatorType.CallOrCallvirt:
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if (index == 2)
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return false;
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if (index == 1)
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return true;
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break;
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default: throw new ApplicationException("Invalid proxy creator type");
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}
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throw new ApplicationException("Could not find field name index");
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}
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static int getFieldNameIndex(MethodDefinition method) {
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var instrs = method.Body.Instructions;
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for (int i = 0; i < instrs.Count; i++) {
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i = ConfuserUtils.findCallMethod(instrs, i, Code.Callvirt, "System.Byte[] System.Text.Encoding::GetBytes(System.Char[],System.Int32,System.Int32)");
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if (i < 0)
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break;
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if (i < 2)
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continue;
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var ldci4 = instrs[i - 2];
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if (!DotNetUtils.isLdcI4(ldci4))
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continue;
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return DotNetUtils.getLdcI4Value(ldci4);
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}
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return -1;
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}
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static int countCalls(MethodDefinition method, string methodFullName) {
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int count = 0;
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foreach (var instr in method.Body.Instructions) {
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@ -1031,6 +1054,11 @@ namespace de4dot.code.deobfuscators.Confuser {
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case ConfuserVersion.v14_r58564:
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minRev = 58564;
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maxRev = 58741;
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return true;
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case ConfuserVersion.v14_r58802:
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minRev = 58802;
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maxRev = 58852;
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return true;
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