Uptime Kuma has Persistentent User Sessions
SummaryAttackers with access to a users' device can gain persistent account access.
This is caused by missing verification of Session Tokens after password changes and/or elapsed inactivity-periods.Details`uptime-kuma` sets JWT tokens for users after successful authentication.These tokens have the following design flaws:After successful login, a JWT token and it is stored in `sessionStorage` or `localStorage`. 
Which of the two is decided based on the `Remember Me` button. 
The users' token is valid without any time limitation, even after long periods of inactivity. 
This increases the risk of session hijacking if, for example, a user forgets to log off and leaves the PC.sessions are only deleted on the client side after a user loggs out, meaning a local attacker could reuse said token with deep system access over the browserIf a user changes a passwordany previously logged in clients are not logged outpreviously issued tokens remained valid foreverThese flaws allow user cookies to remain valid even after changing passwords or being inactive, posing a high security risk.POCPassword resets not deactivating cookiesLog in.Note the user cookie.Change your password.Attempt to log in again with the same cookie.The cookie remains valid despite the password change.Inactivity not deactivating sessionsIn testing, even after a period of over a day of inactivity, the session was still validImpactAnother person with local access to the device could take over the session permanently, even after hours of previous inactivity or a password change.
Such activity would not be obvious to the user (see https://github.com/louislam/uptime-kuma/issues/3481 if you want to help with this).With this gained account access, an attacker can cause:confidentially lossmonitors (including private ones not shared on public status pages)notification providerssettings like `api-keys` (only used for accessing `/metrics`)settings like secrets like the `Steam API Key`maintenance periodsavailability lossby creating a lot of monitors and setting the retention policy very high leading to degraded database performance or out of storageby creating a lot of `HTTP(s) - Browser Engine (Chrome/Chromium) (Beta)` leading to RAM exhaustionintegrity lossby the attacker deleting a monitorby the attacker deleting a monitor's historyby the atacker changing the meaning of a monitor (changing where it points)scope creepIf operated in some restricted network, access to monitors may provide the ability to change the scope of the attack to a different piece of infrastructure, for example via SQL commands to a database server.
We have not classified this as `changed scope` because credentials stored in the application for accessing other systems are existing valid paths across the trust boundary, and the user should be aware of that.