Companies seeking to contain security incidents should concentrate on viruses, according to the Department of Trade and Industry’s twice yearly Information Security Breaches survey. The telephone survey of 1,000 companies, led by PricewaterhouseCoopers LLP, fingers viruses as being the cause of over half of the worst security incidents hitting UK firms in the past two years, with some incidents taking over 50 days to fix.

Check Point’s spokeswoman Caroline Ikomi, pointed out that a major reason for the fact that cleaning up virus outbreaks took so long was the speed and connectivity of firms internal LANs and distributed WAN links, together with unmanaged mobile workers who weren’t quarantined properly and kept reinfecting the network.

Service interruption was the main effect of virus infection, with a quarter of firms surveyed reporting a serious virus infection having major disruption, leading to services such as email being down for a day. Although the virus threat has grown, and 88 percent of UK businesses have broadband Internet connections, the infection rate has fallen by a third since two years ago. However, companies who are infected are suffering an average of one infection per day.

Chris Potter, PricewaterhouseCoopers LLP partner, commented that the best protection is offered by a multi-layer defence of patching and up-to-date anti-virus and intrusion detection software.

Other interesting findings IT managers need to give attention to, is the survey result that a quarter of UK businesses have no anti-spyware capability, one fifth of companies surveyed do not update viral signature files daily and companies installing critical patches within a day suffered fewer virus infections.

The full results of the survey will be launched at Infosecurity Europe in London, 25-27 April.