Malicious emails took the lead from spam as the biggest cyber threat in Australia during April as targeted attacks continued to rise.
In its monthly Internet Security Threats report, Symantec’s MessageLabs division noted April as a prolific month for viruses, with an average of one email in every 271 containing a malicious payload.
This contrasted with a report in March from the vendor, which found that one in every 365 emails in Australia was classed as malicious.
Spam levels fell 5.2 per cent to account for roughly three quarters of all email traffic in Australia.
MessageLabs principal security engineer, Adrian Covic, said the reason for the drop in spam levels may be due to botnets targeting other countries during the period.
"The one thing we have noticed is that there has been an increase in targeted attacks," he told Computerworld Australia. "These are less `spray and pray' where emails containing viruses are sent out randomly but targeted at known vulnerabilties or personal information they know about the user."
Also known as advanced persistent threats, targeted attacks are delivered by email and designed to breach a specific target for the purpose of industrial espionage.
While the vendor does not collect Australian data on the rate of targeted attacks, it identified 11 automated bots operating on a US micro-blogging service, posting messages containing shortened URLs and using a variety of techniques to grab the attention of users.
MessageLabs senior analyst, Paul Wood, said in a statement that the trend in targeted attacks suggested there may be a seasonal pattern.
“The timing is perfect for cyber criminals seeking information about the financial performance of a company, and a carefully crafted attack may be just the means by which they can achieve this,” he said.
Recent natural disasters, such as the Christchurch earthquake in New Zealand and tsunami in Japan, proved a new point of attack for cyber criminals by email during April
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