The Google Safe Browsing service has become an integral part of most of the major browsers, integrating malware alerts, warnings about malicious Web sites and suspicious content. The company has been expanding the capabilities of the service steadily over the last few years, and now Google is adding warnings about deceptive software to the service.

Safe Browsing is a service that Google built several years ago to help warn both users and sit owners about known or potentially malicious content on Web sites. The service, which is built into Chrome, Firefox and other major browsers through an API, will warn users before they land on a site that’s known to distribute malware and also will warn the site owner about the malicious content and give instructions on how to find and remove the dangerous content. The system also has the ability to block malware downloads.

The latest addition to the Safe Browsing toolkit is a visual warning that will alert users about what Google calls “deceptive software”. That essentially means applications that purport to be something they’re not or make some unwanted changes to the user’s browser without his knowledge.

“Starting next week, we’ll be expanding Safe Browsing protection against additional kinds of deceptive software: programs disguised as a helpful download that actually make unexpected changes to your computer—for instance, switching your homepage or other browser settings to ones you don’t want,” Moheeb Abu Rajab, a Google security engineer, said in a post announcing the change.

“We’ll show a warning in Chrome whenever an attempt is made to trick you into downloading and installing such software. (If you still wish to proceed despite the warning, you can access it from your Downloads list.).”

Google’s Safe Browsing service has a massive reach, with the company’s statistics saying it’s used by 1.1 billion people. The number of alerts that the service shows to users has dropped over time, as security warnings for users and site operators have become more effective. In mid-2012, the service was showing as many as 61 million warnings a week, but by this summer it was down to about 15 million a week.