10 SPA Authentication Best Practices

Single Page Applications (SPAs) are becoming increasingly popular as they provide a more interactive and engaging user experience. However, with this increased popularity comes the need for secure authentication. SPAs are vulnerable to a variety of attacks, so it’s important to ensure that authentication is implemented correctly.

In this article, we’ll discuss 10 best practices for implementing authentication in SPAs. By following these best practices, you can ensure that your SPA is secure and your users’ data is protected.

1. Use HTTPS

HTTPS is a secure protocol that encrypts data sent between the client and server. This means that any sensitive information, such as passwords or credit card numbers, will be encrypted before being transmitted over the internet. Without HTTPS, this data could be intercepted by malicious actors, leading to potential security breaches.

Using HTTPS also helps protect against man-in-the-middle attacks, where an attacker intercepts communication between two parties in order to gain access to confidential information. By using HTTPS, you can ensure that all communications are securely encrypted and protected from these types of attacks.

2. Don’t store tokens in local storage

Local storage is vulnerable to XSS attacks, which can allow malicious actors to access the stored tokens. This means that if an attacker gains access to a user’s local storage, they could use the token to gain access to the application as that user.

Instead of storing tokens in local storage, it’s best practice to store them in session storage or cookies with httpOnly flag set. This will help protect against XSS attacks and ensure that your users’ data remains secure.

3. Store tokens in memory cache

When a user logs in, the application should store an authentication token in memory. This token is used to authenticate requests from the client-side and verify that the user has access to certain resources. Storing tokens in memory cache ensures that they are not stored on the hard drive or sent over the network, which can be intercepted by malicious actors.

Additionally, storing tokens in memory cache allows for faster retrieval of data since it does not require a database lookup. This helps improve performance and makes sure that users have quick access to their data.

4. Keep tokens short-lived

When a user logs in, the SPA will receive an authentication token. This token is used to authenticate requests from the client-side application to the server. If this token is not short-lived, it can be stolen and used by malicious actors to gain access to your system.

To prevent this, you should set up your tokens with a short expiration time (e.g., 15 minutes). This way, if someone does steal the token, they won’t have much time to use it before it expires. Additionally, you should also implement refresh tokens that allow users to renew their session without having to log in again.

5. Revoke tokens on logout

When a user logs out of an SPA, the authentication token is still stored in the browser. This means that if someone else were to gain access to the computer, they could use the token to log back into the application without needing any credentials.

To prevent this from happening, it’s important to revoke the token when a user logs out. This will ensure that the token can no longer be used and that the user must re-authenticate with their credentials before being able to access the application again.

6. Use JWT with an asymmetric algorithm (RS256)

JWT is a secure and compact way to store authentication information. It’s also easy to use, since it can be sent in the HTTP Authorization header of each request. An asymmetric algorithm (RS256) provides an extra layer of security by using two different keys for signing and verifying tokens. This means that only the server has access to the private key used to sign the token, while the public key is available to anyone who needs to verify the token.

Using JWT with an asymmetric algorithm ensures that your SPA authentication process is secure and reliable.

7. Avoid using custom claims unless absolutely necessary

Custom claims are additional pieces of information that can be added to a user’s authentication token. These claims can contain sensitive data, such as the user’s role or access level.

The problem with custom claims is that they increase the size of the authentication token and can slow down the authentication process. Additionally, if the custom claim contains sensitive data, it could potentially be exposed in an attack. Therefore, it’s best to avoid using custom claims unless absolutely necessary.

8. Implement token refresh

When a user logs in to an SPA, they are issued a token that is used for authentication. This token has a limited lifespan and will eventually expire. If the token expires while the user is still logged in, they will be unable to access any protected resources until they log out and back in again.

To avoid this issue, you should implement token refresh. Token refresh allows your application to automatically detect when a token is about to expire and request a new one from the server before it does. This ensures that users can remain logged in without interruption.

9. Use a whitelist for CORS requests

Cross-origin resource sharing (CORS) is a mechanism that allows restricted resources on a web page to be requested from another domain outside the domain from which the first resource was served. This can open up your application to potential security risks, as malicious actors could use CORS requests to gain access to sensitive data or even take control of user accounts.

By using a whitelist for CORS requests, you can ensure that only trusted domains are allowed to make requests to your application. This will help protect your users and their data from unauthorized access.

10. Use the state parameter

The state parameter is a unique, randomly generated string that is sent along with the authentication request. It helps to prevent cross-site request forgery (CSRF) attacks by ensuring that the response from the authorization server matches the original request. This means that an attacker cannot hijack the user’s session and gain access to their account without knowing the exact value of the state parameter.

By using the state parameter, you can ensure that your SPA authentication process is secure and reliable.