Spam accounts for nearly 200 billion messages a day or approximately 90% of all email worldwide, the 2008 Cisco Annual Security Report revealed.
The report, which highlights security threats and trends, also found that more online criminals are using real email accounts with legitimate web mail providers to send spam. This method, known as ‘reputation hijacking’, makes spam harder to detect and block.
According to Cisco estimates, spam resulting from email reputation hijacking of the top three web mail providers accounted for less than 1% of all spam worldwide, but made up 7.6% of the providers’ mail traffic.
Additionally, researchers have seen a 90% growth in threats originating from legitimate domains, doubling 2007 figures.
Cisco is warning of more targeted attacks by cybercriminals in 2009 as the overall number of disclosed vulnerabilities this year grew by 11.5% over 2007.
In contrast, the volume of malware successfully circulated through email attachments is declining - over the past two years (2007-2008), the number of such attacks decreased by 50% when compared to the previous two years (2005-2006).
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