A botnet identification module identifies members of one or more botnets based upon network traffic destined to one or more servers over time, and provides sets of botnet sources to a traffic monitoring module. Each set of botnet sources includes a plurality of source identifiers of end stations acting as part of a corresponding botnet. A traffic monitoring module receives the sets of botnet sources from the botnet identification module, and upon a receipt of traffic identified as malicious that was sent by a source identified within one of the sets of botnet sources, activates a protection mechanism with regard to all traffic from all of the sources identified by the one of the sets of botnet sources for an amount of time.