Spam levels took another jump last month with the number of unwanted messages bearing malware tripling in volume, according to the latest State of Spam and Phishing report from Symantec.

In a report which will make grim reading for IT security administrators, spam made up 92.51 per cent of all messages in August, compared with 91.89 per cent in July, while .zip attachment spam saw a four-fold increase from the previous month.

The research also noted a wave of .html attachments with malicious JavaScript as the volume of malicious spam more than tripled. There was better news for the EMEA region, however, with the amount of spam originating in the region declining over five percentage points to just 43.17 per cent of all spam.

On the phishing front, emails designed to harvest sensitive information increased by one per cent as the boom in automated toolkits continued to have a significant impact. Phishing web sites created by automated toolkits increased by 92 per cent, the report found.