People using eBay or purchasing items through websites that have a secure login have had their card details 'harvested' by Trojan Horse viruses and put up for sale on a Russian website.

Victims uncovered in a Sunday Times investigation included people working in the computer industry who had no idea their details were for sale for as little as £1 on foreign websites.

Carole Theriault, from security company Sophos, said that having a firewall and relevant protective software was vital - but it wouldn't give 100% protection.

She told the paper:

"It's like driving a car. There's always a risk. You just have to do everything you can to reduce it."