What is Insecure Deserialization in applications?

Insecure deserialization is a defect if it is present in your application. This defect can put your application at risk. As a software developer, it is important to know about this. And learn about techniques that help to prevent this defect in the application. Today in the digital world almost all the applications manipulate the program data with the help of serialization and deserialization.
A lot of web applications share data around in the form of JSON or XML packets. The transmission and receiving of data among application micro-services use serialization and deserialization of the data.

Since this is standard practice to serialize and deserialize data in applications, Hackers see this as an opening to inject malicious code into your application. And sometimes they get success in trapping your data during this process. Once your application receives the data and starts the data deserialization to put this data back in place. As soon as this deserialization is completed, your application starts processing the data, then the code injected by hackers also gets executed. This execution causes damage to your application as planned by the hacker.

Applications use a lot of utilities to serialize data and then deserialize it back. It is a normal process in application development. Hackers are aware of these development processes and they try to take advantage of this.
If you are not using proper serialization and deserialization techniques then you are causing a vulnerability. Such situations become perfect examples of Insecure deserialization.

How to avoid Insecure deserialization Vulnerability?

  1. Apply integrity checks and encryption

Packing and securing is a basic step when you plan to transmit anything from one place to another. The same applies to the data when you are serializing it (packing it) you should apply encryption to it. Similarly when you are receiving it then you should first make sure what you’ve received is what you are expecting.
Once you get the data perform a data integrity check, decrypt the data, and validate it. If you get the satisfactory results then only you should start executing this data.
If you see tampering of data then it is best practice to discard the data and request a fresh copy from the sender.
This simple security practice can save you from a lot of damage.

2. Track the incidents with logs

As per the above solution, we can detect the issue with our data. But just discarding the data and requesting again is not the best idea. To make our systems more secure and responsive we should generate alerts to the admins. These alerts will help you get informed with any malicious activity going on in your system or network.
As a developer, we always make sure that our applications have proper logging and alerting mechanism in place. We should take advantage of those mechanisms to alert if any data deserialization issue is detected by the system.
This will help in improving our application about any code issue and it will also help us in finding out that someone is trying to create trouble for you.

3. Secure Design for Isolation

Software Design is the first phase of development for any application.
During the design phase itself, we know the data transmission and receiving modules requirements.
It is recommended that during the design phase itself we should focus on the isolation of the modules which will handle the serialization and deserialization in our application.
Isolation means we should apply more security measures of data validation on these modules. We apply a similar approach to protect our systems against injection attacks.
We can take the help of threat modeling techniques also while we are designing our applications.