Microsoft on Tuesday released free software that people can use to protect computers against viruses, spyware and other malicious codes in arsenals of cyber criminals.

Microsoft Security Essentials is available for download at microsoft.com/security_essentials and is built on technology that the global software giant uses in computer security programs it designs for businesses.

“With Microsoft Security Essentials, consumers can get high-quality protection that is easy to get and easy to use, and it won’t get in their way,” said Amy Barzdukas, general manager for consumer security at Microsoft.

“Consumers have told us that they want the protection of real-time security software but we know that too many are either unwilling or unable to pay for it, and so end up unprotected.”

Microsoft hopes that the free software will be broadly adopted, particularly by those who have not been vigilant about protecting computers from hackers, and thereby “increase security across the entire Windows ecosystem.”

More than 90 percent of the computers worldwide run on Windows operating systems made by the US technology firm.

“Microsoft is helping to reduce some of the barriers that constrain consumers from running (anti-virus software),” said IDC security analyst Jon Crotty. “Microsoft is focused on the challenges that prevent consumers from running up-to-date anti-virus software today, particularly in emerging markets where there is a growing prevalence of malware.”

Security Essentials is designed to run behind the scenes, defending machines against infection by malicious computer codes.

The real-time nature of the software means it is automatically kept up-to-date regarding viruses.

Computer security specialty firm Symantec downplayed the Microsoft offering, saying it is lightweight and isn’t tuned for new forms of attack being used by hackers.

Symantec referred to Security Essentials as a stripped-down version of an old Microsoft OneCare product that got poor ratings.

“From a security perspective, this Microsoft tool offers reduced defences at a critical point in the battle against cyber crime,” Symantec said of the free offering that competes with Norton products sold by the firm.

“Unique malware and social engineering tricks fly under the radar of traditional signature-based technology alone which is what is employed by free security tools such as Microsoft’s,” it said.