monocul.us/de4dot-cex
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Detect Confuser 1.4 r58802 proxy methods creator

Browse Source
This commit is contained in:
de4dot 2012-08-10 22:10:44 +02:00
parent e3e051b876
commit 9cf4887061
1 changed files with 67 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

106
de4dot.code/deobfuscators/Confuser/ProxyCallFixer.cs
View File

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