Brian Krebs, writing at Krebs on Security:
The makers of MacKeeper — a much-maligned software utility many consider to be little more than scareware that targets Mac users — have acknowledged a breach that exposed the usernames, passwords and other information on more than 13 million customers and, er…users. Perhaps more interestingly, the guy who found and reported the breach doesn’t even own a Mac, and discovered the data trove merely by browsing Shodan — a specialized search engine that looks for and indexes virtually anything that gets connected to the Internet.
A couple things here:
If you’ve been using MacKeeper, stop. Seriously, just stop.
Even after you stop, change your password immediately or, better yet, delete your account entirely.
MacKeeper is nothing but a scammy program designed to prey on Mac users’ fear. There is nothing useful or actually safe about it, so just get rid of the thing.