JS Framework Security: Common Risks & Fixes

TL;DR

Yes, popular JavaScript frameworks (React, Angular, Vue etc.) can introduce security risks if not used carefully. These often stem from Cross-Site Scripting (XSS), injection flaws, and dependency vulnerabilities. Regular updates, input validation, output encoding, secure coding practices, and using a Content Security Policy (CSP) are key to mitigating these issues.

Understanding the Risks

JavaScript frameworks make building web apps faster, but they don’t automatically make them secure. Here’s what you need to watch out for:

• Cross-Site Scripting (XSS): This is a big one. If your framework lets user input appear on the page without proper sanitisation, attackers can inject malicious scripts.
• Injection Flaws: Similar to XSS, but applies to other contexts like database queries or command execution if you’re not careful with how data flows through your application.
• Dependency Vulnerabilities: Frameworks rely on lots of external packages (dependencies). These can have security holes that attackers exploit.
• Client-Side Logic Issues: Sensitive logic shouldn’t be entirely handled on the client side, as it’s easily visible and manipulable.

How to Secure Your JS Framework App

Here’s a step-by-step guide to improve your application’s cyber security:

1. Keep Everything Updated

1. Framework Updates: Regularly update your JavaScript framework to the latest version. These updates often include critical security patches.

   npm update

   or

   yarn upgrade

2. Dependency Updates: Use a dependency management tool to identify and update vulnerable packages.

   npm audit fix

   or

   yarn audit --fix

2. Input Validation & Sanitisation

1. Server-Side Validation: Always validate user input on the server side, even if you also do client-side validation. Client-side checks can be bypassed.
2. Sanitise Data: Remove or encode potentially harmful characters from user input before displaying it in your application. Frameworks often provide built-in functions for this:
   • React: Use libraries like dompurify to sanitise HTML.
   • Angular: Angular’s template engine automatically encodes output by default, but be careful when using innerHTML.
   • Vue: Vue's templating system also provides automatic encoding, but review custom components carefully.

3. Output Encoding

Ensure that data displayed on the page is properly encoded to prevent XSS attacks. This converts potentially harmful characters into safe representations.

4. Content Security Policy (CSP)

1. Implement CSP: A CSP tells the browser which sources of content are allowed for your application. This can significantly reduce the risk of XSS.

   Content-Security-Policy: default-src 'self'; script-src 'self' https://trusted-cdn.example.com;

2. Start Strict, Then Relax: Begin with a very restrictive CSP and gradually relax it as needed, carefully monitoring for compatibility issues.

5. Secure Coding Practices

• Avoid eval(): Never use the eval() function to execute user-supplied code. It's a major security risk.
• Be Careful with Third-Party Libraries: Only use trusted libraries from reputable sources. Review their code and dependencies before using them.
• Handle Authentication & Authorisation Securely: Don’t store sensitive information on the client side. Use secure authentication protocols (e.g., OAuth 2.0) and properly implement authorisation checks.

6. Regular Security Scanning

1. Static Code Analysis: Tools like ESLint with security plugins can identify potential vulnerabilities in your code.
2. Dynamic Application Security Testing (DAST): Use tools to scan your running application for XSS, injection flaws, and other vulnerabilities.