UDP flood

Using UDP (User Datagram Protocol) computers can exchange short messages called datagrams.  During UDP attack hacker will send a large amount of UDP packets with spoofed source addresses at victim. As UDP is a connectionless protocol it does not require a connection to be set up between computers to be processed. Victim system will search for applications using the port and if it can’t find any it will respond with a ICMP Destination Unreachable packet.

With many UDP packets sent, the victim system will respond with a huge amount of ICMP packets thereby not being able to respond to legimate traffic.

How to stop and prevent UDP attack?

1.  Disable all unused UDP services
2. Block all IP addresses sending UDP packets to ports not used by any application installed to the server.