Microsoft has filed civil suits against businesses believed to be responsible for placing advertising that hides malware.

The company's microsoftontheissues.com blog claimed that Microsoft has filed five civil lawsuits, the first of their kind against ‘malvertising'. Microsoft claimed that it is working with other providers of online advertising platforms to mitigate the threat posed by malvertising.

The blog said: “We're now taking that effort a step further. Our filings in King County Superior Court in Seattle outline how we believe the defendants operated, but in general, malvertising works by camouflaging malicious code as harmless online advertisements.”

The lawsuits allege that individuals using the business names Soft Solutions, Direct Ad, qiweroqw.com, ITmeter and ote2008.info used malvertisements to distribute malicious software or present deceptive websites that peddled scareware to unsuspecting internet users.

The blog said: “Although we don't yet know the names of the specific individuals behind these acts, we are filing these cases to help uncover the people responsible and prevent them from continuing their exploits.

“We hope that today's filings will help deter malvertising in the future, but meanwhile, adopting a few good habits can help you avoid online scams and ensure the safest computing experience possible.”

Tom Kelchner, research office manager at Sunbelt Software, said: “Bringing the suits gives Microsoft's attorneys the power to request subpoenas to get contact information from ISPs or other businesses and possibly identify the defendants.

“According to other stories out there today, we suspect the trail just might lead to a click-fraud group named the Ukrainian Fan Club by way of the Bahamas. Texas-based security firm Click Forensics connected the recent malicious ads that delivered rogue security products on the New York Times website to a botnet that was once based in servers in the Bahamas – called the Bahama botnet.”