Business users were the worst offenders in this week's spread of the Goner worm and many firms were slow to update antiviral protection during the outbreak.

An analysis of the spread of the worm by managed services firm MessageLabs reveals that 93 per cent of the infected emails it blocked in the first day of the outbreak came from business domains. On the second day of the outbreak, 84 per cent of all copies of the virus were coming from business - suggesting a sizeable proportion of firms fail to update antiviral protection in a timely fashion. By contrast, the vast majority of BadTrans.B viruses -the last major piece of malware to go feral before Goner -stopped by MessageLabs came from home users. Goner is a relatively unsophisticated worm in its design and the psychological tricks it attempts to pull in order to get people infected. Users are used to getting little programs and Xmas cards by email at this time of year and are more likely to click on them, he suggests. MessageLabs has blocked more than 230,000 copies of Goner since it first appeared on the Internet this week, with one in 30 emails containing the virus at the peak of epidemic. Incidents of the virus began tailing off yesterday and MessageLabs has blocked only around 5,000 copies of Goner so far today.