From isc.sans.edu
At the SANS Internet Storm Center (ISC), handlers frequently analyze data submitted from DShield participants to determine activity trends and potential attacks. A few days ago on May 31st, I observed a small anomaly for port 45740 and decided to monitor it for the next 3 days or so. There was a huge spike in number of sources/day and reports/day recorded on May 31st as shown in Figure 1.