public static bool IsNewer45Decryption(MethodDef method)
{
if (method == null || method.Body == null)
{
return(false);
}
var instrs = method.Body.Instructions;
for (int i = 0; i < instrs.Count - 4; i++)
{
var ldci4 = instrs[i];
if (!ldci4.IsLdcI4() || ldci4.GetLdcI4Value() != 4)
{
continue;
}
if (instrs[i + 1].OpCode.Code != Code.Mul)
{
continue;
}
ldci4 = instrs[i + 2];
if (!ldci4.IsLdcI4() || ldci4.GetLdcI4Value() != 4)
{
continue;
}
if (instrs[i + 3].OpCode.Code != Code.Ldloca_S && instrs[i + 3].OpCode.Code != Code.Ldloca)
{
continue;
}
var call = instrs[i + 4];
if (call.OpCode.Code != Code.Call)
{
continue;
}
if (!DotNetUtils.IsPinvokeMethod(call.Operand as MethodDef, "kernel32", "VirtualProtect"))
{
continue;
}
return(true);
}
return(false);
}
bool FindFirstBlocks(Block block, TamperBlocks tamperBlocks, IList <Block> allBlocks, IList <Local> locals)
{
if (!block.LastInstr.IsBrfalse())
{
return(false);
}
/*
* ldc.i4.0
* stloc X
* call GetExecutingAssembly()
* stloc Y
* ldloc Y
* callvirt Location
* ldc.i4.1
* ldloca X
* call StrongNameSignatureVerificationEx
* pop / brfalse bad_code
* ldloc X
* brfalse bad_code
* ldloc Y
* callvirt FullName()
* ldstr "......"
* callvirt EndsWith(string)
* brfalse bad_code / brtrue good_code
*/
var instrs = block.Instructions;
int end = instrs.Count - 1;
Instr instr;
IMethod method;
tamperBlocks.type = Type.V1;
int index = 0;
int start = FindCallMethod(block, index, true, (calledMethod) => calledMethod.ToString() == "System.Reflection.Assembly System.Reflection.Assembly::GetExecutingAssembly()");
if (start < 0)
{
return(false);
}
index = start + 1;
instr = instrs[--start];
if (!instr.IsStloc())
{
return(false);
}
var loc0 = Instr.GetLocalVar(locals, instr);
instr = instrs[--start];
if (!instr.IsLdcI4())
{
return(false);
}
index = FindCallMethod(block, index, false, (calledMethod) => calledMethod.ToString() == "System.String System.Reflection.Assembly::get_Location()");
if (index < 0)
{
return(false);
}
index++;
index = FindCallMethod(block, index, false, (calledMethod) => {
tamperBlocks.pinvokeMethod = DotNetUtils.GetMethod(module, calledMethod);
return(DotNetUtils.IsPinvokeMethod(tamperBlocks.pinvokeMethod, "mscorwks", "StrongNameSignatureVerificationEx"));
});
if (index < 0)
{
return(false);
}
index++;
if (!instrs[index].IsBrfalse())
{
if (instrs[index].OpCode.Code != Code.Pop)
{
return(false);
}
instr = instrs[index + 1];
if (!instr.IsLdloc() || Instr.GetLocalVar(locals, instr) != loc0)
{
return(false);
}
if (!instrs[index + 2].IsBrfalse())
{
return(false);
}
tamperBlocks.type = Type.V1;
tamperBlocks.first = new BlockInfo {
Block = block,
Start = start,
End = end,
};
}
else
{
tamperBlocks.type = Type.V2;
tamperBlocks.first = new BlockInfo {
Block = block,
Start = start,
End = end,
};
block = block.FallThrough;
if (block == null)
{
return(false);
}
instrs = block.Instructions;
index = 0;
instr = instrs[index];
if (!instr.IsLdloc() || Instr.GetLocalVar(locals, instr) != loc0)
{
return(false);
}
if (!instrs[index + 1].IsBrfalse())
{
return(false);
}
}
block = block.FallThrough;
instrs = block.Instructions;
start = end = 0;
instr = instrs[end++];
if (!instr.IsLdloc())
{
return(false);
}
instr = instrs[end++];
if (instr.OpCode != OpCodes.Callvirt)
{
return(false);
}
method = instr.Operand as IMethod;
if (method == null || method.ToString() != "System.String System.Reflection.Assembly::get_FullName()")
{
return(false);
}
instr = instrs[end++];
if (instr.OpCode != OpCodes.Ldstr)
{
return(false);
}
instr = instrs[end++];
if (instr.OpCode != OpCodes.Callvirt)
{
return(false);
}
method = instr.Operand as IMethod;
if (method == null || method.ToString() != "System.Boolean System.String::EndsWith(System.String)")
{
return(false);
}
instr = instrs[end++];
if (!instr.IsBrfalse() && !instr.IsBrtrue())
{
return(false);
}
end--;
tamperBlocks.second = new BlockInfo {
Block = block,
Start = start,
End = end,
};
return(true);
}
