ScanSafe reports that at its highest peak in 1Q09, 58% of Web malware blocks were zero day threats. On average, the rate of zero day malware blocks was 20% in 1Q09, meaning that companies using signature-based scanning alone could have been heavily exposed to malware during this period. ScanSafe noted that the rate of Web-delivered malware increased sharply in the first quarter of 2009 anoth …[more]