Postini data centers blocked more than 100 million viruses every day during the height of a virus attack in recent months. The majority (over 50%) of these viruses delivered through fake notices of underreported income from the IRS, and another large contingent of virus-infected emails included false package tracking attachments. Spammers also sent an email that asked for the recipient’s user name and password to their webmail account, and then used the compromised account to generate spam.

Postini continues to capture many of these phishing attempts before they reach your users’ inboxes. For unprotected mail systems, only a tiny fraction of the recipients need to be fooled for spammers to add hundreds of computers to their botnets every day.

For more information on this attack, see Spam & Virus Trends from Postini on the Google Enterprise Blog.