The Taterf worm has increased infections by 156 per cent over the past six months.
According to the latest bi-annual Microsoft security intelligence report, the worm has moved from two million infections earlier this year to 4.9 million with the most recent analysis.
It claimed that the ‘Taterf' worm is infecting seven machines every hour in the UK, with it targeting multiplayer online roll playing games such as Rainbow Island and World of Warcraft.
Unbeknown to the online gamer, the worm steals their personal account information via a downloadable executable file. It targets both home and work computers, and is primarily designed to infect a machine's USB stick or similar memory drive that can then be transported into a corporate network and infiltrate from inside their firewall defences.
The report stated that this is marking a resurgence of worms with infections doubling in the first half of this year, primarily due to the Conficker worm. This has seen worms becoming the second most prevalent threat category in the first half of 2009.
Microsoft UK's head of security and privacy Cliff Evans, said: “Over a six month period it [Taterf] certainly stepped up. Also with Koobface, this whole area is a big change. In the UK it is still true that malware is still dominant.
“It is spreading in a normal worm way. Starting by the dominance of worms into organisations – business are hit by worms, consumers by malware. Because of the way it spreads, it is a big increase. Conficker played a part but criminals have seen a way to make money.”
The report also claimed that Microsoft has detected and cleaned 13.4 million computers of rogue security software, down from 16.8 million, which it called ‘an improvement, but still a significant threat'.
Evans said: “We've cleaned less than last time, it is down from 16.8 million but we are still seeing it around and detecting it so I hope we are protecting it from getting it again. The category is still very important and we still advise on keeping things up to date.”