Dancho Danchev reports in the Zero Day blog on ZDNet that dangerous malware is included with some free Mac screensavers available at 7art-screensavers.com. Intego researchers have identified the malware as the OSX/OpinionSpy spyware.
In a nutshell, "it injects code, without user intervention, into Safari, Firefox and iChat, and copies personal data from these applications." It then regularly sends the information, such as e-mail addresses, iChat message headers, and URLs to a number of servers.
You can get the full details both in the ZDNet blog above or from the Mac Security blog.
Selena has been at TechRepublic since 2002. She is currently a Senior Editor with a background in technical writing, editing, and research. She edits Data Center, Linux and Open Source, Apple in the Enterprise, The Enterprise Cloud, Web Designer, and IT Security blogs.