"People need to be extra vigilant and understand that even sites they know and trust can be compromised through attacks such as SQL injection attacks, while businesses need to ensure they take the necessary precautions to block all the latest malicious sites," said Wood.

"With the ever advancing world of cyber crime, nothing can be taken at face value."

One consequence was that the days of reputation filtering services could be numbered as a primary defence. If the domains were fraudulent sub-domains exploiting legitimate domains, this would be difficult to defend against on such a scale.

In Wood's view the only hope was to embrace hosted services, the business MessageLabs is in. "There are things you can do in the cloud that you simply can't so on your own computer."