Malware trends have shown no sign of slowing, according to F-Secure

Despite efforts to eradicate spam from e-mail servers and private mailboxes, this modern plague has continued to spread.

Another trend in malware writing is the rapid increase in new trojans and bots. Unlike indiscriminate assaults by viruses and worms, Trojans can be delivered to target organisations with great precision.

Mobile viruses have also continued to make news, says the company. So far, the worst is a trojan called Skulls, which replaces the system applications with non-functional versions, so that all but the telephone's basic functions are disabled. More worrying for smartphone owners is the arrival of Commwarrior, a virus that spreads via Bluetooth and MMS messages.