In this lesson, you will learn how to bypass the standard token expiration lifecycle to immediately invalidate a user's session when security policies change.
The Challenge of Stateless Tokens
When you use JWTs (JSON Web Tokens) for authentication, the server is "stateless." Once a client receives a token, they can use it until it expires, regardless of whether you’ve updated their permissions or disabled their account in your database. Because the server trusts the signature of the token without checking the database on every request, the user maintains access until the exp claim hits.
To bridge this gap, we implement "Real-Time Revocation."
Implementing SecurityStampValidator
The most effective way to force an immediate check is by using the SecurityStampValidator. ASP.NET Core Identity keeps a SecurityStamp in the user's database record. When this stamp changes (e.g., you call userManager.UpdateSecurityStampAsync(user)), the next time the user’s cookie or token is validated, the system compares the stamp in their claims to the one in the database.
If they don't match, the system automatically rejects the authentication.
How to trigger a check
You can wire this into your application configuration to ensure that the security stamp is verified on every request:
builder.Services.Configure<SecurityStampValidatorOptions>(options =>
{
// Validate the stamp every 0 minutes (immediate check)
options.ValidationInterval = TimeSpan.Zero;
});
By setting this to TimeSpan.Zero, you tell the framework to verify the SecurityStamp against the database on every single request. While this adds a slight performance overhead due to the database hit, it grants you the ability to "kill" a session instantly.
Use Cases for Real-Time Revocation
- Account Suspension: An admin marks a user as "Banned" in the dashboard.
- Password Resets: You force all active sessions to terminate after a sensitive security change.
- Role/Permission Updates: When a user is demoted from a highly privileged role, you want their elevated access to vanish before their token naturally expires.
Key Takeaway: By utilizing the SecurityStampValidator and a short validation interval, you override stateless token behavior to ensure that security policy updates are enforced globally and immediately.