Protecting .NET applications that use the MVVM pattern

September 20, 2018 3258 Views Johnny

Model–View–ViewModel (MVVM) is a common pattern used in WPF, Xamarin, and other types of .NET applications. There are different ways to apply the MVVM pattern, but they all share a few underlying concepts. I’d like to discuss these concepts, and how to successfully configure protection with Dotfuscator for MVVM-based apps.

Please consider this basic WPF application, which displays a group of employees in a grid format:

The Model for this application is the Employee object. As with any MVVM application, the model has three characteristics:

1.It implements INotifyPropertyChanged.

2. Because it implements INotifyPropertyChanged, it contains an event of type PropertyChangedEventHandler.

3. It has an OnPropertyChanged method which, in conjunction with the PropertyChanged event, is responsible for syncing the state of the object data with the user interface.

If we look at any of the properties within Employee, we notice that they call OnPropertyChanged with a string argument containing the property name.

This string value will be compared at runtime to the name of the property, so in my Dotfuscator config, I need to exclude such properties from Renaming.

If I do not exclude these properties, Dotfuscator will rename them, and the string comparison will fail. That causes my Employee grid to be empty after obfuscation.

As I mentioned earlier, there are many possible implementations of the MVVM pattern, but most of them are affected by obfuscation this same way. The property name on the Model contains a string representation of that property which is passed to OnPropertyChanged. Because of this, a rename exclusion is required in Dotfuscator.

You may download the full example here.

If you have any feedback on this topic, or other topics you would like us to discuss in the Support Corner, please feel free to contact us at support [at] preemptive [dot] com.

Latest Blog Posts

Dotfuscator 6.0 Beta: Entering the Next Era of Dotfuscator

Today we're announcing the first new major-version release of Dotfuscator in thirteen years: Dotfuscator Professional 6.0 Beta. It's an exciting new release with major new capabilities, but before we get into that, let's take a look at why it's been so long since we had a major release and why we're choosing to do one now.

For development teams, adding Dotfuscator to a build pipeline can often seem like a challenge; the value it adds is mostly gained by the surrounding business, and the cost of adding it is mostly borne by the development team. We understand that constraint, which is why we focus on making Dotfuscator as easy to integrate and maintain as possible. If you're a long-time user of Dotfuscator, you've probably experienced that - release after release of painless upgrades. That's our "first do no harm" philosophy in action.

The dynamic type in C# provides flexibility that is not available in other statically-typed languages. Since its introduction in C# 4.0 (.NET 4.5), we have worked with customers who wanted to know more about how dynamic types are impacted by the obfuscation process.

Malicious actors — like any thieves — live by a simple rule: If the front door is locked, break the window.

It’s why threats like fileless malware and crypto-jacking have seen substantial gains over last few years. It’s why — despite increasing employee education and IT training — hackers are still hooking phish by developing more sophisticated and authentic-looking email spoofs. Cybercriminal communities, meanwhile, continue to grow on the dark web, allowing attackers to share info, purchase exploit kits and identify potential targets.

What does this mean for CISOs? That typical defense efforts are being outpaced as familiar attack vectors are replaced with non-traditional threats. But it’s not all bad news; here are three questions every CISO needs to ask to help close the doors, bolt the windows and leave hackers out in the cold.

Gabriel, you have been in the security industry for over 2 decades. You have seen many different tools and services. Why create a company around something as specific as obfuscation and in-app protection?

Our customers build a lot of really innovative apps that enable their users and customers to do new and cool things. These apps frequently run on untrusted client computers/devices and they control access to customer’s sensitive data or critical devices.

And after all the effort of designing, building, debugging, and deploying their applications, the last thing they want is for an attacker to steal their work or use it to look for vulnerabilities to break into their system.

Long ago, we built a Java code optimizer, but it became clear to us that our customer cared more about the obfuscation effects of the optimization than the actual performance improvement. That is when we really began to focus on app protection. First with Java, then .NET, Android, iOS, Xamarin, JavaScript, etc.

Gartner calls In-App Protection “crucial” in their July 2019 Market Guide for In-App Protection In-App Protection. The guide’s summary advises security and risk management leaders to “take due care in protecting their application clients” in order to avoid “security failure.”

This raises the question – what constitutes “due care?” Obviously, no development organization looks to recklessly expose their applications or sensitive data to attack or compromise. On the other hand, over-engineered (or poorly engineered) security controls can quickly lead to excessive development costs, performance and quality issues, and, ultimately, unacceptable user experiences. While terms and terminology may vary, there is broad consensus on how to best define “due care” for any given application/user scenario.

Protecting .NET applications that use the MVVM pattern

Dotfuscator 6.0 Beta: Entering the Next Era of Dotfuscator

Protecting C# Applications That Use Dynamic Types

Non-Traditional Attack Vectors: Three Questions Every CISO Needs to Ask

Q&A With PreEmptive CEO Gabriel Torok

Gabriel, you have been in the security industry for over 2 decades. You have seen many different tools and services. Why create a company around something as specific as obfuscation and in-app protection?

The Secret to Effective In-App Protection

Latest Blog Posts

Dotfuscator 6.0 Beta: Entering the Next Era of Dotfuscator

Introducing JSDefender: PreEmptive Protection now includes JavaScript

Protecting C# Applications That Use Dynamic Types

Non-Traditional Attack Vectors: Three Questions Every CISO Needs to Ask

Q&A With PreEmptive CEO Gabriel Torok

Twitter