The threat from worms and Trojans is on the increase, according to a bi-annual report from software giant Microsoft.

In the seventh biannual Microsoft Security Intelligence Report, the software giant claims that infections from worms have more than doubled between January and June 2009, although Trojans were still the biggest cause for concern. The company also highlighted a notable increase in scareware related infections, where customers are typically persuaded into purchasing bogus antivirus software.

The report claims to have taken extensive coverage of the market, as making use of Microsoft’s comprehensive footprint on consumer as well as corporate computers and the web. Data has also been taken from the company’s Bing search engine as well as various applications, including Live OneCare, Forefront Protection for Exchange cloud service, Malicious Software Removal Tool, and Windows Defender.

The report attributes much of the increase to the ‘Conficker‘ worm, also known as Downadup or Kido and less known ‘Taterf’.

The advice from Microsoft for users was to ensure that they kept an up-to-date antivirus software programme and to exercise caution whilst online.

“We’d recommend, in addition to automatic updates, firewalls and up-to-date anti-virus, that users never log into an account unless they’re on a machine they trust, and don’t download cracks or tips unless from a trusted server,” Cliff Evans, head of Microsoft UK told

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