A spyware application that surreptitiously scans chat logs and hard drives of unsuspecting Mac users has found its way onto three of the more popular download sites, security researchers said Tuesday. Dubbed OSX/OpinionSpy, the spyware is distributed through software available on sites including Softpedia, MacUpdate, and VersionTracker, according to Intego, a provider of anti-virus software for Macs. The app isn't contained in the downloads themselves, but rather gets downloaded during the installation process, Intego said. A Windows version of the program has existed since at least 2008. Once installed, OpinionSpy scans files and folders on all attached hard drives and regularly sends data in encrypted form to several servers, according to Intego. It also injects code into the Safari, Firefox, and iChat applications and mines them for email addresses, message headers, and other data. The program remains active even if the screensaver or other application that was originally downloaded is uninstalled. "The fact that this application collects data in this manner, and that it opens a backdoor, makes it a very serious security threat," Intego researchers wrote. "In addition, the risk of it collecting sensitive data such as user names, passwords and credit card numbers, makes this a very high-risk spyware." Apple's OS X operating system has long been regarded as a haven from the huge base of malware that regularly targets users of Microsoft's Windows. The Windows threat has grown so large that Google has begun advising its new employees to use alternates, The Financial Times has reported. Mac's most ardent supporters have long claimed the platform is more inherently secure than Windows, a perception Apple marketers have been happy to perpetuate. But a more plausible explanation, advanced by Charlie Miller and other white-hat hackers who regularly exploit Apple security bugs, is that the platform isn't sufficiently big enough to justify the investment of hardened crime gangs. Intego identified the apps installing OpinionSpy as the MishInc FLV To Mp3 media converter and screensavers made by the company 7art-screensavers. More details about the spyware are here.