I recently received two Facebook email notifications that set my security spider-sense tingling. Nothing was obviously wrong with the messages, which said that my friend had tagged a photo of me and commented on it. But something about a reference to an app named 'Who stalks into your profile' just didn't feel right.
So I checked it out. I dug into the email header to make sure that it was from Facebook - it was. A search for the app's name didn't turn up any warnings. The app's installation page didn't give me any obvious clues, either. Still, I let my paranoia have its day, and I sat on the app.
Sure enough, it was a scam, and an ingenious one. When anyone installed the supposed stalker app, it first created a photo montage of friends' images and then commented on that montage. Facebook duly sent out 'your friend tagged a photo of you' messages, effectively advertising the scam app, which was created to generate illicit online advertising revenue.
Facebook, with its millions of users, has become a major target for online crooks who try to use malicious apps for everything from phishing to spam to a first step toward installing more dangerous malware onto your PC. Facebook is by no means sitting still in the face of these threats, and it removed the profile-stalking app within a day after I received its email lure (and this removal pulls it from all user profiles as well).
But because Facebook lets anyone with an account create and distribute apps, users must be on guard against the inevitable rogue apps to come. The alternative would be for Facebook to test programs before allowing its users to add them, as Apple does with iPhone apps; but Facebook says it fears that such vetting could inhibit the free and open atmosphere that led to its success, and it doesn't have any plans to change its approach.
Some simple measures can help you identify, or at least mitigate, the threats. For starters, Facebook has a security page - facebook.com/security - with advice and warnings about ongoing scams.
Also, be especially wary of any app that claims to let you do something that you can't normally do - such as permitting you to see who's viewing your profile.
To help guard against a friend's rogue app being able to harvest your profile data, head to Account, Privacy Settings, and then click Applications and websites. Then click the settings for 'What your friends can share about you', and deselect anything you wouldn't want a scammer to see. Keep in mind that an app can't pick up your email address without first asking your explicit permission: be careful about what you approve.
Tips like these can help, but in the end, no hard-and-fast rules can positively identify all possible threats. And since the apps live on Facebook's site, you don't have a file on your hard drive to scan or upload to Virustotal.com.
Still, you can simply wait. If you see a post, an email, or even a photo-tagging comment pushing an app that you'd like to try out, and you can't find anything definite about it, let it lie for a day or two. Facebook may pull it within that time, in part because of reports from users who didn't have the same patience.