Advanced Infrastructure Penetration Testing

Spanning Tree Protocol attacks

The Spanning Tree Protocol (STP) was developed by Radia Perlman in 1985 to solve the problem of Ethernet loops, but before diving into STPs, let's go back to the root causes of this issue. If a broadcast storm occurs, you will lose your network availability. This happens when we have an Ethernet loop. As simple example, in the following diagram, we have three connected switches. If a switch sends a broadcast to the other two switches, they will receive and rebroadcast it by forwarding it through all ports because they couldn't find the address. Also, they will go for a repeating loop called a broadcast storm:

This way, the STP appeared to solve this networking issue by blocking the redundant paths, thanks to  ...