[SECURITY] Topology spoofing via LLDP

It has been reported that it is possible for an attacker to spoof network topology via LLDP. Details are in this paper:

http://www.internetsociety.org/sites/default/files/10_4_2.pdf

Two fixes are proposed:

1) Implement nonces for the LLDP messages, although this leaves a problem with MITM attacks where a host can copy LLDP from one point in the topology to other point. That would create a fake link between two OpenFlow switches.

2) Implement a mechanism that somehow warns administrator about unexpected topology changes.

MITRE has been contacted requesting a CVE name for this issue.