90 percent of e-mail is spam, Symantec says

Spammers seem to be working a little bit harder these days, according to Symantec, which reported Tuesday that unsolicited e-mail made up 90.4 percent of messages on corporate networks last month.

That represents a 5.1 percent increase over last month's numbers, but it's nothing out of the ordinary. For years, spam has made up somewhere between 80 percent and 95 percent of all e-mail on the Internet.

Symantec reported that nearly 58 percent of spam is now coming from so-called botnets --networks of hacked computers that can be misused by criminals to steal financial information, launch attacks or send spam. The worst of the spamming botnets -- called Donbot -- generates 18.2 percent of all spam, according to Symantec.