Unsolicited email messages accounted for 90.4% of messages sent on all corporate networks in the US last month, according to tech firm Symantec.
The firm claims that spam has increased by 5.1% over last month’s figures, and that 58% of junk messages are now coming from “botnets”, which are a series of hacked computers often used for criminal purposes.
Adam O’Donnell, research with anti-spam company Cloudmark, told Macworld.com that botnets can be rented on the black market to anyone but spammers are now using different ways to bypass corporate filtering schemes.
“Some of the larger ISPs are seeing a lot of non-bot-driven spam,” O’Donnell said. These new spam campaigns will now rent legitimate networks and then direct spam towards a particular internet service provider.
O’Donnell also said spammers are now targeting social networking sites, evidenced by the recent attacks on Facebook and Twitter.