Howdy.

Back in 2019 I reverse engineered the lyft bikes api to unlock them from my bed. It's one of my favorite stories, and after telling it dozens of times I finally decided to write it up in its full technical glory.

I used to love learning about security through blog posts/writeups, so I tried to include as much detail as possible. Let me know if you like this style!

You never know with corporations. Consequences range from "federal pound-in-the-ass prison" or "here is $500".

You'd generally expect a company like Lyft to pin its certificates, so it's notable that they don't. Any ideas as to why?

Another "bike hack" if you're into that (from 2004 and in German):

https://www.ccc.de/hackabike/

> Geofence bypass: As far as I understand, there's no easy way to enforce a geofence server-side other than timing, consistency, etc. You sort of just have to trust whatever the phone tells you.

There's no fool proof method but you can make it very hard and impractical.

Both Apple and Google offer attestation mechanisms to confirm the integrity of the App and Device Environment that it's running on. This ensures that the API requests are coming from an attested device.

To mitigate the MITM attack you can use TLS Certificate pinning on sensitive API requests.

You could have the server side API provide a session specific signing token that the App uses to sign payloads attached to API calls.