Stealing your identity is now as easy as taking your picture. That’s the gist of a new study from Carnegie Mellon, on the potential dangers of facial-recognition technology. If you’ve used Websites like Facebook or Google-Plus lately, then you probably know all about this stuff.  It’s software that automatically identifies people in photos, so you can easily “tag” those people, and share the pictures with them.

In this new study, researchers used a webcam to take pictures of volunteers. Then, they plugged the photos into facial-recognition software you can get for free on Google. The result? Using only those photos, researchers correctly identified the names of a-third of the volunteers. Then, they matched the names to public information found on Facebook.  And once they figured out each person’s age and hometown, the researchers had a one-in-four chance of correctly guessing their Social Security number!

Experts say this is a big problem when you consider we’re uploading nearly 3 billion photos to sites like Facebook every month. They say a single photo – or a single status update – isn’t dangerous by itself.  The worry is that all our posts lumped together are making it easier for criminals with enough time and know-how to steal your identity.  And this study shows just how easy it is!

Researchers say if you see an option for automatic photo “tagging” on Facebook or Google, turn it off!