6.5 4000 Series—UDP Signatures
6.5.3 UDP Port Scans signature
The following is a UDP Port Scans Signature: 4001-UDP port scan (severity 5, reconnaissance): This signature is triggered when a series of UDP connections to a number of different destination ports on a specific host have been initiated. This indicates that a reconnaissance sweep of your network may be in progress. This may be the prelude to a more serious attack.