Figures suggesting that fake anti-virus packages are allowing cybercrooks to make more than €10m a month are been described as little better than guesswork. Vendors across the industry are warning that scarewore packages - which attempt to trick would-be marks into handing over their hard-earned cash for packages that claim to resolve fictitious infections - are a growing problem.

But estimates by Panda Security that 30 million Windows PCs have been infected with fake antivirus programs have met with skepticism from a rival vendor. Graham Cluley, senior technology consultant at Sophos, question Panda's assumption in reaching its figures, which he suggests are little better than back of the envelope calculations.