The number of computers infected with malware designed to steal personal and financial information has risen 600% in the last year, according to security outfit PandaLabs.
The firm says it receives nearly 37,000 samples of new viruses, worms, Trojans and other types of Internet threats every day and suggests the recession is contributing to the growing threat.
Trojans are the most common threat - accounting for 71% of the samples - and are mostly aimed at stealing bank details or credit card numbers as well as passwords for other commercial services.
Around three percent of Web users have now been the victim of malware designed to steal financial information, says PandaLabs.
The firm claims the rapid rise is in part due to cybercriminals exploring new channels for propagating threats as well as new sources of revenue.
Fraudsters previously tended to target users' online banking information by getting them to enter their user name and password in a spoof site. Now potential victims are taken to any platform or site in which their bank details may be stored or where they might have to enter them.
This has resulted in payments platforms like PayPal and e-commerce sites becoming increasingly popular targets.
Similarly, whereas e-mail was practically the only channel used in the past for contacting victims, many other methods, such as social networking sites and SMS messages, are now being used.
Luis Corrons, technical director, PandaLabs, says: "Maybe one of the reasons of this increase is the economic crisis along with the big business that selling this information on the black market, such as credit card numbers, Paypal or Ebay accounts, etc. We have also seen an increase of the distribution and infection of this kind of malware through social networks."