Breaking and Fixing Token Revocation: A Real-Time Exploration

TL;DR

• Successfully revoked tokens when logging out of iOS.
• Explored how to emulate authentication failures.
• Discovered undocumented token paths in the code.
• Utilized mocking to simulate error scenarios.
• Uncovered the use of max age parameters and off-time claims with Auth0.

Today was all about understanding token handling in my iOS setup. I started with success: logging out on iOS successfully revoked the “El Tokarino” token. Knowing this was crucial as it sets the baseline functionality for subsequent tests and experiments. But the real intrigue came when considering how to simulate failures that didn’t naturally occur, especially when logs looked too consistently smooth.

Problem: Simulate Token Failure

My method involved identifying potential failure points in the token refresh and login process. The goal was to compel an error, ideally by corrupting a token, to see how the system manages unexpected issues. My immediate thought was to programmatically throw errors after key operations - like after signing in - since these boundaries define critical functionality.

Exploration: Inserting Fail Points

I reviewed the code to identify promising spots where errors could be injected. Initially, getOrRefreshCredentials seemed like a logical point because it’s pivotal in handling token refreshes. However, after more thought, I focused on the web authorization process, wondering what would happen if I interrupted this with an error. I knew it would have to be caught and handled gracefully by existing mechanisms unless I unintentionally bypassed something crucial. Importantly, I wanted to ensure that any test conclusions correlated with real-world use.

Insight: Mocking Auth0 Functions

A lightbulb moment struck post-bathroom break: I could mock Auth0’s functions and check if expected function calls occurred during an error. This would mean simulating a function throwing an error and observing if a revoke happens. These tests aren’t just useful - they generated valuable insight into ensuring token security across authentications.

Deep Dive: Max Age and Off Time

I needed clarity on managing the lifespan of a session token. Auth0’s max_age parameter was center stage. It determines how often a user must re-authenticate after a period of inactivity. During my research on Auth0 settings, I unpacked how this interacted with the auth_time claim in the ID token. Realizing it automatically contained auth_time was a revelation, simplifying future token handling.

Conclusion

By closely examining logs, ensuring no traceback errors, and verifying API conditions versus expected behavior, I strengthened my approach to token management. Monitoring for refresh cooldown and troubleshooting spuriously repeated refresh calls rounded this off.

My next steps involve probing deeper into refresh logic, especially understanding refresh token rotations for more robust, future-proof testing environments. Real-time exploration not only challenges assumptions but also reveals the quirks and nuances that automated tests might miss. This journey through token management was both tedious and enlightening, showing once more that authenticating users is an ever-evolving art.