Firms are taking more time to recover from virus attacks, according to a new report, and costs are rising. However, they are now more likely to suffer from a string of small attacks throughout the year, rather than from a single major attack.

A survey by Icsa Labs of firms with more than 500 PCs found they took an average of 23 person days to recover from each virus disaster in 2002, up from 20 days in 2001. Icsa Labs, a division of security specialist TruSecure, defined a disaster as a simultaneous attack on 25 or more PCs, or an attack causing major damage.

The average cost of recovery from each disaster increased from £45,000 in 2001 to £52,000 last year. About three-quarters of organisations said the virus problem was worse in 2002 than in 2001. The monthly infection rate among 306 medium to large firms increased to 105 per 1,000 PCs, up from 103 in 2001, and 91 in 2000.

The 80 disasters reported in 2002 were caused by four viruses in nine months. This differed from previous years, when most disasters were reported in a single month and were caused by a single virus - for example Melissa in 1999 and Loveletter in 2000.

Email attachments were the most frequent source of attacks, and infected 86 percent of firms. Internet downloads and Web browsing were responsible for 11 percent and four percent of infections respectively.

The main problems caused by viruses were loss of productivity and unavailability of machines. Lost data and corrupted files were also key concerns. Icsa Labs advised firms to keep using desktop antivirus solutions in conjunction with email gateway or SMTP server protection, file attachment filtering and Web browsing defences.

Rates of infection
Monthly infections per 1,000 PCs

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