PandaLabs, the anti-malware arm of Panda Security reckons it detected some 25 million new strains of malware during 2009, making it the outstanding trend of the last 12 months.
To put that in context, the malware total for the previous 19 years of Panda's 20-year history was 15 million.
This latest surge of activity included countless new examples of banker Trojans as well as a host of fake antivirus programs (rogueware).
Panda's tear-end report also draws attention to the resurgence of traditional viruses, previously on the verge of extinction, such as Conficker, Sality or the veteran Virutas.
The firm said some 92% of all email traffic was identified as spam.
The year saw waves of junk mail related to celebrity scandals or deaths (real or fictitious), swine flu, compromising videos of politicians, and so forth. Automobile and electrical industries were the worst affected, followed by government institutions, the firm said.
Social networks (mainly Facebook, Twitter and YouTube), and SEO attacks (directing users to malware-laden websites) have been favoured by cyber-criminals, who have been consolidating underground business models to increase revenues.
The Annual Malware Report also examines how individual countries and regions have been affected throughout the year, based on the data gathered from computers scanned and disinfected free of charge with Panda ActiveScan.
Taiwan tops the rankings, followed by Russia, Poland, Turkey, Colombia, Argentina and Spain. Countries suffering fewest infections include Portugal and Sweden (or Sweeden, as the Pandas have it). The UK was the fourth lowest in the overall rankings.
Last year also saw a rise in the number of news stories related to cyber-attacks with political motives or targets, suggesting that this is no longer the preserve of sci-fi movies and conspiracy theorists and is now becoming a reality.
PandaLabs has predicted that the amount of malware in circulation will continue to grow during 2010. Windows 7 will surely attract the interest of hackers when it comes to designing new malware, and attacks on Mac will increase. While we are likely to witness more politically motivated attacks the report concludes that, once again, this will not be the year of the mobile phone virus.
PandaLabs Annual Malware Report is here (pdf).