Book Image

ASP.NET Core 5 Secure Coding Cookbook

By : Roman Canlas
Book Image

ASP.NET Core 5 Secure Coding Cookbook

By: Roman Canlas

Overview of this book

ASP.NET Core developers are often presented with security test results showing the vulnerabilities found in their web apps. While the report may provide some high-level fix suggestions, it does not specify the exact steps that you need to take to resolve or fix weaknesses discovered by these tests. In ASP.NET Secure Coding Cookbook, you’ll start by learning the fundamental concepts of secure coding and then gradually progress to identifying common web app vulnerabilities in code. As you progress, you’ll cover recipes for fixing security misconfigurations in ASP.NET Core web apps. The book further demonstrates how you can resolve different types of Cross-Site Scripting. A dedicated section also takes you through fixing miscellaneous vulnerabilities that are no longer in the OWASP Top 10 list. This book features a recipe-style format, with each recipe containing sample unsecure code that presents the problem and corresponding solutions to eliminate the security bug. You’ll be able to follow along with each step of the exercise and use the accompanying sample ASP.NET Core solution to practice writing secure code. By the end of this book, you’ll be able to identify unsecure code causing different security flaws in ASP.NET Core web apps and you’ll have gained hands-on experience in removing vulnerabilities and security defects from your code.
Table of Contents (15 chapters)

Fixing unsafe deserialization

Json.NET had always been a popular framework for processing JSON among .NET developers until .NET recently introduced its own set of serializer/deserializer classes under the System.Text.Json namespace. This new set of classes removes prior versions of .NET Core's dependency on the library.

Json.NET has a type-handling feature that can make your ASP.NET Core web application vulnerable to insecure deserialization if misused. The automatic type handling will allow the Json.NET stream deserializer to use the declared .NET type in an incoming request. Allowing your app to automatically deserialize objects based on the declared .NET type from an untrusted source can be harmful and may cause the instantiation of unexpected objects, causing arbitrary code execution in the host. In this recipe, we will fix this unsafe deserialization and prevent harmful automatic type handling.

Getting ready

For the recipes of this chapter, we will need the sample...