Is a multitenant web app built on Apache Cassandra more resilient against DoS attacks?

Question

Imagine a multitenant web app that stores data in a Apache Cassandra cluster, with fairly many nodes.

Now assume that:

1. Mallory launches a DoS attack against one tenant. (Perhaps that tenant is a company that people don't like, for some reason.)
2. It's a layer 7 DoS attack. I mean, it's not a SYN flood attack or something like that, but a "hand crafted" attack that actually reaches the database layer of the web app.
3. [Data stored on the Cassandra nodes] is sorted by tenant id. That is, data belonging to the tenant-under-attack is located on fairly few nodes, in comparison to the total number of nodes in the Cassandra cluster.

With these assumptions, other tenants should be largely unaffected by the DoS attack? _{Assuming that their data resides on [nodes that host no data belonging to the tenant under attack], and neglecting how the attack affects the application/web-server-layer and network I/O.}

And, in a manner, Cassandra is more resilient against DoS attacks?

(In comparison to e.g. a RDBMS or MongoDB or CouchDB.)

Answer 1

Well if you have multi-tenant app, you need to monitor each tenant service, and in case of fail, redirect him to a working cluster. Basically, what you do in this case, you redirect affected customer to a blackhole, while the rest remains unaffected. For example, if each of your tenants is using different FQDN, you can block affected customer on L7 load balancer you mentioned. In any case, you can make load balancer to detect DoS and block it automatically. Ideally you need to work out the load balancing using geo-graphic regions and DOS detection as well per-tenant monitoring, so all of this at once will give you automation you are looking for. Also the security and user isolation is also here important, that the CPU spike will not affect another tenant.