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)

Output encoding using HtmlEncoder

HTML encoding converts special characters so that the browser will interpret the text correctly and not render it as HTML. For instance, a string may contain a less than character <, and in HTML standards, this is an HTML entity being used to open and close tags. This needs to be escaped into &lt; to preserve the meaning of the text.

The protection that escaping output provides lies in preventing the attacker from changing the intent or the input's purpose when it is parsed by the interpreter. This stops the malicious actor from trying to execute scripts within the HTML context.

The following table displays the most common HTML entities and their encoded counterparts. This is by no means a complete list:

Table 1.1 – HTML entities

Table 1.1 – HTML entities

In this recipe, you will learn how to use HtmlEncoder to escape output in HTML.

Getting ready

Using Visual Studio Code, open the sample Online Banking app folder...