How do you handle cross-site scripting (XSS) and cross-site request forgery (CSRF) attacks in a .NET Core Web API?

Cross-site scripting (XSS) and cross-site request forgery (CSRF) are two common types of attacks that can affect the security of a .NET Core Web API. Here are some ways to handle these attacks:

Cross-site scripting (XSS): This type of attack occurs when an attacker injects malicious code into a website, which is then executed by the victim's browser. To prevent this type of attack, you can:

• Use the built-in ASP.NET Core Request Validation feature to sanitize user input and avoid accepting untrusted input.
• Use Content Security Policy (CSP) to restrict the types of content that can be loaded on your website.
• Encode output that is displayed to users, using HTML encoding or URL encoding, to ensure that it is not interpreted as code.

 

Cross-site request forgery (CSRF): This type of attack occurs when an attacker tricks a user into performing an action on a website without their consent. To prevent this type of attack, you can:

• Use anti-forgery tokens, which are unique tokens that are generated for each user session and used to validate requests. You can generate anti-forgery tokens in ASP.NET Core using the [ValidateAntiForgeryToken] attribute or the [AutoValidateAntiforgeryToken] attribute.
• Use the SameSite attribute to ensure that cookies are only sent with requests that originate from the same site.
• Limit the use of HTTP methods that have side effects, such as POST, PUT, DELETE, and PATCH, to prevent attackers from making unauthorized changes to your data.

By implementing these measures, you can help protect your .NET Core Web API from these common types of attacks.