Globally, attacks increased to 77 attacks per day from only one to two attacks per week five years ago when the attacks were first discovered. Among the different types of security attacks -- from e-mails to website and domain attacks -- e-mail attacks were lower in volume but are "one of the most damaging types of malicious attacks", said MessageLabs Intelligence senior analyst Paul Wood.

Wood added: "Although the number of unique attack exploits being deployed has diminished slightly, the number of attacks used by each exploit has increased."

Spam attacks decreased 4.2 per cent from last month to 87.5 per cent while viruses decreased 0.01 percentage points to one in 221.9 e-mails. Phishing attacks also decreased 0.06 percentage points to one in 488 e-mails.

Countries in Asia experienced a similar trend. Hong Kong posted highest spam rates at 92.4 per cent in October from 92.7 per cent. India had the highest virus rate with one in 84.8 e-mails from one in 177.1 last month.