Hello SAP BTP Security Experts,
I'm helping my clients to get their CAP based multitenancy apps deployed to BTP Cloud Foundry. For one app we've executed a pentest and got the finding that there is no rate limiting in place.
Without such a rate limit it is possible that a Client using Tenant A issues so many requests that it slows down requests to made by Clients to Tenants B and C.
In the documentation Developing Resilient Apps on SAP BTP: Rate Limiting I've only found some general overview but no concrete tips. Also SAP BTP, Cloud Foundry Runtime - Scope and Limitations doesn't provide the details I would need. I've also checked the SAP Support page: My Trust Center without success.
As far as I know SAP BTP Cloud Foundry in general is accessed via a F5 Load Balancer. It would be good to know if already here any rate limiting is implemented.
The first endpoint that I can influence in the Cloud Foundry environment is the approuter. In the @sap/approuter documentation I haven't found any hint regarding rate limiting or other limits that I could set. Looking at the Sizing Guide for HTTP Traffic it seems that the approuter can handle quite some load. If I would like to implement my own rate limiting (which I think isn't a good idea) I could follow the guide on Extending Application Router. But I hope there is a better way.
Looking forward for your input.
CU
Gregor