Security has always been one of the most important concerns in the application software development and having a robust security model drives the success of the software application. .Net is a software development platform that is created by Microsoft and helps in developing different types of applications.

Code access security often provides powerful and explicit mechanism that helps to implement security. Most application codes simply use the infrastructure that is implemented by .NET, but in some cases, additional security is needed and this is done by extending the security system.

By using the .NET enforced permissions and other security features in your code, you can prevent malicious codes from accessing the information and performing other undesirable actions.

Together with this, you can also strike a balance between the usability and security by using trusted codes.

Here we will discuss the different way you can design the codes that can help to strengthen the security system of your application.

Securing the Resource Access:

While designing and writing your .net development codes, you should protect and also limit the access of resources to the codes.

Especially when you are using any codes of unknown origin, always remember that it is very important to ensure that your codes are secure and do not use any partial trusted codes or use code access security.

It is recommended not to use .NET remoting and any distributed component object model.  You should not load or execute any codes without putting alternative security measure.

Security-Neutral Codes:

This does nothing explicit with the security and runs with the permissions that it receives. Applications that fail to catch security exceptions can often result in an unhandled exception, and the security neutral codes take the benefits of the security technologies in .NET and its library has some special characteristics that the developers should understand.

If your codes don’t have the corresponding permission, then it won’t run as specified.  Even if the codes has the corresponding permission, any application code that it calls should also have similar permission to work.

Application Code That is Not Reusable:

If your .NET code is part of an application and is not called by any other codes, then security is simple and any special coding may not be needed. But remember that malicious codes can call your codes.

Though code access security may stop the malicious codes from accessing any important resources, but such codes could read the values of the fields or properties and may contain sensitive information.

Library Codes That Expose the Protected Resources:

This is an approach that is the most powerful and of course potentially dangerous one for security coding. The library will serve as an interface for other codes in order to access some resources that are not available otherwise, just like the .NET classes that enforce the permissions for the resources that they use.

Whenever a resource is exposed, the code must ask for the permission that is appropriate to the resource that it should perform a security checking and then assert its rights in order to perform the actual operation.

Using Managed Wrappers For Native Code Implementation:

In this case, some useful functionalities are added in the native code so that it is available in the managed code. The managed wrappers are quick and easy to write by either using the platform invoke or the COM interop.

In case you do this, the callers of your wrappers should have unmanaged code rights for success. This means that any code that is downloaded from the internet or the intranet won’t work properly with the wrappers.

So, instead of giving any unmanaged code right to the applications using the wrappers, it is a good idea to give these right only to the wrappers codes. In case the underlying functionality does not expose any resources and the implementation is safe, the wrapper needs to assert its rights that allow any code to call through it.

When the resources are involved, then the security coding should be same as the library codes. Since the wrapper is exposing the callers to these resources, any verification of the safety of the native code is essential and this is the responsibility of the wrapper.