Spammers have adapted a new technique for sending malicious emails, according to Cisco. The company reports that spammers have evolved their approach and the most popular technique to emerge these days is called hailstorm spamming, in which the entire spam campaign is sent within a very short timeframe. This comes in reaction to the popularity of snowshoe spamming in recent years, which security companies have begun to fight off. This style of spamming depends on placing the source of the malicious emails across a large number of IPs, unleashing a flood over several days or weeks.