Spam volumes and the number of malicious web sites saw big falls last month, according to the latest Symantec.cloud MessageLabs Intelligence report.
Spam dropped 6.4 per cent from last month, making up 72.9 per cent of all email traffic. The number of web sites blocked for carrying malicious code fell by nearly 20 per cent, while virus and phishing levels remained virtually unchanged.
"The reduction in spam has to do with several factors. A major one is the recent take-down of several large-scale botnets, which were considered large sources of spam, as well as other malicious and nuisance traffic," Phil Hochmuth, programme manager for IDC's security products service, told V3.co.uk.
"Another factor is that wide-scale blanket attacks, using spam combined with malicious links or attachments, have given way to more targeted attacks on individuals, both high-level and low-level, within organisations."
Security companies are also having a much greater effect on spam volumes, Hochmuth said, particularly with cloud malware-sensing capabilities being built into many services.
The latest report confirmed that the number of targeted attacks on individuals and companies is rising. Attack rates grew to their second highest recorded rate since a spike around last year's G20 summit set the record.
Matt Sergeant, senior anti-spam technologies officer at Symantec.cloud, told V3.co.uk that the long-term trend of targeted attacks is rising, and that social networks are a particular target.
While spam volumes are falling, they are always likely to be a factor for security managers.
"It's always going to be there, as long as people can run any program on their computer," he said.
"Within the email space, there's always going to be some kind of level of infection, even with current systems efficient in the 99.999 per cent range."
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