Refresh Token Rotation

Refresh token rotation is a security mechanism used to protect the integrity and security of refresh tokens in an authentication flow.

In a typical authentication scenario, a refresh token is issued to a client after a user successfully authenticates. This refresh token can be used to obtain new access tokens once the original access token expires.

However, static refresh tokens present a potential security risk if they are compromised. To mitigate this risk, refresh token rotation is employed.

What is Refresh Token Rotation?

Refresh token rotation is a process where a new refresh token is issued every time the client uses a refresh token to obtain a new access token. The previous refresh token is invalidated immediately after it's used.

This ensures that only one valid refresh token exists for a session at any given time. If an attacker intercepts a refresh token, they won't be able to use it after the legitimate client uses it, thus reducing the window of opportunity for abuse.

Security Benefits of Refresh Token Rotation

Reduced Attack Window

By rotating refresh tokens, the window of opportunity for an attacker to use a stolen refresh token is significantly reduced. Even if a refresh token is intercepted, it will only be valid until the client uses it to obtain a new access token.

Detection of Malicious Activity

If a refresh token is used more than once, it may indicate that the token has been compromised. Descope can detect this scenario, enabling the system to take appropriate actions such as revoking all tokens associated with the user session, notifying the user, or requiring re-authentication.

Enhanced Session Management

Refresh token rotation ensures that long-lived sessions remain secure. Even if a session lasts for an extended period, the frequent rotation of refresh tokens prevents the same token from being reused, minimizing the risk of token abuse.

How We Implement Refresh Token Rotation

In Descope, refresh token rotation is automatically handled as part of the OAuth 2.0 flow. When a refresh token is used to obtain a new access token, Descope will issue a new refresh token along with the new access token. The old refresh token is immediately invalidated, ensuring that it can no longer be used.

The steps involved in refresh token rotation with Descope are as follows:

1. User Authentication: The user authenticates with Descope, and a refresh token along with an access token is issued to the client.
2. Access Token Expiration: The access token eventually expires, and the client uses the refresh token to request a new access token.
3. Refresh Token Rotation: Descope validates the refresh token, issues a new access token, and rotates the refresh token by issuing a new one while invalidating the old token.
4. Secure Token Storage: The client stores the new refresh token securely, replacing the old one.

In addition to this, we have automatic reuse detection built in to automatically invalidate refresh tokens if there is an attempt to refresh the session token involving an older refresh token.

Conclusion

Refresh token rotation is a crucial security measure in maintaining the integrity of your authentication system. By regularly rotating refresh tokens, Descope enhances the security of user sessions, reducing the risks associated with token theft and unauthorized access. Implementing this feature within your applications is straightforward with Descope, providing a robust defense against potential security threats.