Trying to figure what type of attack this is

edit

There is a nmap scan buried in the capture. Is that what you're looking for?
Work down through the Statistics menus.
Protocol Hierarchy - not very interesting for this capture
Conversations - will help to find a very large conversation that can be excluded from analysis
Also pay attention to the ports being accessed. Does this look like expected traffic?
Endpoints - who are the chatty nodes and what are they doing?
Good luck!