Member declaration renames, but usage (call) remains the same!

Question

Member declaration renames, but usage (call) remains the same!

KLO128 opened this issue 2 years ago · 2 comments

LoGiC.NET obfuscator looks good, but I have found some issues with renaming...

My Changes in LoGiC.NET

I had to made some cosmetic changes in LoGiC.NET for my needs.

I have excluded InvalidMetadata protection, because IIS server does not support such protected libraries with invalid metadata.

Protection[] protections = new Protection[]
     {
             new Renamer(),
             new AntiTamper(),
             new JunkDefs(),
             new StringEncryption(),
             new AntiDe4dot(),
             new ControlFlow(),
             new IntEncoding(),
             new ProxyAdder(),
             // new InvalidMetadata()
     };

Renamer: I have commented out renaming of namespaces and data types (classes, interfaces, structs, delegates, enums,...)

//if (CanRename(type))
//{
//    // Hide namespace
//    type.Namespace = string.Empty;
//    type.Name = Randomizer.String(MemberRenamer.StringLength());
//}

Renamer: I have commented out renaming of instance fields, because it did not work - it renamed some fields and then called the original name...

public static bool CanRename(object obj)
{
    DefAnalyzer analyze;
    if (obj is MethodDef method) analyze = new MethodDefAnalyzer();
    else if (obj is PropertyDef prop) analyze = new PropertyDefAnalyzer();
    else if (obj is EventDef) analyze = new EventDefAnalyzer();
    else if (obj is FieldDef) return false;
    else if (obj is Parameter) analyze = new ParameterAnalyzer();
    else if (obj is TypeDef) return false;
    else return false;

    return analyze.Execute(obj);
}

Configuration: I had to exclude ProxyCallsIntensity due to stack overflowing...
```
ProxyCallsIntensity: 0
```

My Project Issue

In my project, I came to an exception of calling an internal method with the original name in the same class's public constructor, but the declaration of the method was renamed after the obfuscation!!! :-(

I think it could be caused by not supported version of .NET (.NET 6).
...or there must be some issue with the privacy: The constructor's public modifier, where it is called, is not the privacy modifier of the called method. I think, that program attaches wrong metadata of privacy to this method in some code branch, and it assumes it is public, so it does not rename it when calling it.

public MyService(IDependency dependency) : base(dependency)
{
    InitData();
}
...
// original InitData()
internal void rgrehrehrehzhwefwegweh()
{
}

Unfortunately, I could not reproduce this issue creating a new sample project (TestAppToObfuse), but I have found a similar one...

Sample Project Issue 1

I have created a new sample project to reproduce the renaming issue and I have explored another issue.
Reproduction of the issue was not successful: similar case of the declaration and the call was renamed correctly, but it calls a property setter helper method called set_PreviousResult(), which does not exist in the original neither obfuscated code.
PreviousResult property only exists and I have used the old syntax of getter and setter (if it matters).

Steps to Reproduce

You can download the github project TestAppToObfuse.
Obfuscate the libraries TestAppToObfuse.Services and TestAppToObfuse.Services.Impl
Copy the result libraries' DLLs into the Libs folder...

...and run TestAppToObfuse.exe, you will get the exception:

Method not found: 'Void TestAppToObfuse.Services.SomeServiceBase.set_PreviousResult(System.String)`

Sample Project Small Issue 2

As you can see after disassembling, protected non-internal method DoItInner(string what) of SomeService is renamed - it should be not in my opinion, because it is visible outside the assembly as it is protected method in a public class. I know, that it is not a public well known interface, but some class could count with the original name as it would like to inherit it.

Many thanks for any help to solve these issues! (Specially My Project Issue or Sample Project Issue 1).

Answer 1 · 2022-10-11T15:44:09.000Z

Hello, and sorry for answering late!

About this issue, it's most likely because LoGiC.NET has issues with dependencies. Specifically, it doesn't quite support applications with dependencies, especially for renaming.

For the second small issue, this can probably be fixed with some simple checks.

Hope this helps!

Answer 2 · 2022-10-14T10:25:23.000Z

Hello,
Thank You for the response.
I am planning to invest into Babel Obfuscator as I have not found anything usable and free for .NET 6.
Babel Obfuscator disassembled codes are unfortunately more readable, but functional. Maybe using the Enterprise feature (code encryption) will make it more unreadable. Dotfuscator is maybe good, but very expensive.