How do you secure your front-end code?

1 Use HTTPS

HTTPS is the secure version of HTTP, the protocol that transfers data between your browser and the server. HTTPS encrypts the data, making it harder for attackers to intercept, modify, or steal it. HTTPS also verifies the identity of the server, preventing phishing and spoofing attacks. To use HTTPS, obtain a valid SSL certificate from a trusted authority and configure your server to redirect all HTTP requests to HTTPS. Also use tools like Let's Encrypt or Cloudflare to get free SSL certificates and enable HTTPS easily.

2 Validate inputs and outputs

Input validation is the process of checking the data that users enter or upload to your web application, such as forms, files, or cookies. Input validation can prevent malicious injections, such as SQL, NoSQL, or command injections, that can compromise your database or server. Use regular expressions, whitelists, or sanitizers to filter and validate the inputs. Output validation is the process of checking the data that your web application sends or displays to the users, such as HTML, JSON, or XML. Output validation can prevent cross-site scripting (XSS), which is a type of attack that injects malicious code into your web pages. You can use encoding, escaping, or templating to filter and validate the outputs.

3 Implement CSP and SRI

Content Security Policy (CSP) is a security mechanism that allows you to control what resources your web application can load and execute, such as scripts, images, or fonts. CSP can prevent XSS and other attacks that rely on loading external or inline code. Implement CSP by adding a meta tag or a header to your web pages, and specifying the sources and directives that you want to allow or block. Subresource Integrity (SRI) is a security feature that allows you to verify the integrity of the external scripts or stylesheets that your web application loads, such as libraries or frameworks. SRI can prevent tampering or corruption of these resources by attackers. Implement SRI by adding a hash attribute to your script or link tags, and generating the hash value using tools like SRI Hash Generator.

4 Store sensitive data securely

Storing sensitive data securely is crucial to prevent data breaches and comply with privacy regulations. Avoid storing sensitive data in your front-end code, such as in variables, local storage, or cookies. Instead, store sensitive data in your back-end server or database, and use encryption, hashing, or salting to protect it. Use secure methods to transfer sensitive data between your front-end and your back-end, such as HTTPS, JWT, or OAuth.

5 Update dependencies and libraries

Dependencies and libraries are external code you use in your front-end development, such as frameworks, plugins, or tools. Dependencies and libraries can improve your productivity and functionality, but they can also introduce vulnerabilities and bugs that can affect your security. Update your dependencies and libraries regularly, and use tools like npm audit or Snyk to check for any security issues or patches. Also use only trusted and reputable sources for your dependencies and libraries, and avoid using outdated or unmaintained ones.

6 Test and audit your code

Testing and auditing your code is the process of finding and fixing any errors, bugs, or vulnerabilities that can compromise your security. Testing and auditing your code can help you improve your code quality, performance, and reliability, as well as prevent potential attacks or breaches. Use tools like Jest, Mocha, or Cypress to test your front-end code, and tools like ESLint, Prettier, or SonarQube to audit your code style, complexity, and security. Also use tools like OWASP ZAP, Nmap, or Burp Suite to perform penetration testing or ethical hacking on your web application, and simulate real-world scenarios and attacks.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?