By its very nature as a social network, Facebook is a veritable gold mine for cyber criminals. Recognizing the threat of account hijacking and compromise, Facebook has implemented new security features to protect Facebook accounts, including a one-time password via mobile phone text message.
Compromising a Facebook account exposes a variety of personal information about the legitimate account holder that can be used for identity theft, or might help deduce passwords and other details enabling the attacker to hijack other accounts. The ability to hijack a Facebook account also provides the attacker with a credible and trusted resource that can be used to con and extort the social network of friends connected to the compromised account.
A post on The Facebook Blog announces, "we're launching one-time passwords to make it safer to use public computers in places like hotels, cafes or airports. If you have any concerns about security of the computer you're using while accessing Facebook, we can text you a one-time password to use instead of your regular password."
While general use of a computer is acceptable from a coffee shop, an airport terminal, or hanging in a hotel lobby, it is a bad idea to do anything that requires logging into an account. The Wi-Fi connections in public hotspots are usually not encrypted or secured in any way--leaving all traffic open to interception--and you just never know what prying eyes might be shoulder surfing as you type.
A security control like this one-time password changes that, though. Relying on physical possession of the designated mobile phone is a security control that can't be simply guessed or cracked. With a lifespan of only 20 minutes, the one-time password reduces the window of opportunity for stealing the password and compromising the Facebook account to almost nothing.
Keep in mind, though, that the one-time password can also have the opposite of the desired effect. If the designated mobile phone is lost or stolen, its "new owner" can probably deduce enough personal information to determine if the legitimate owner has a Facebook account--especially if it's an iPhone or other smartphone and it has a Facebook app. With mobile phone in hand, there is no reason the attacker can't simply text "otp" to 32665 and get one-time access to the account as well.
The one-time password from Facebook is the latest security control, but not the first, to capitalize on text messaging and the mobile phone. Just a couple weeks ago, Microsoft added new security controls to protect Hotmail accounts--one of which relies on texting a password reset code to the mobile phone number associated with the Web-mail account.
The Facebook blog post also explains the new remote logout feature. "The ability to sign out of Facebook remotely is now available to everyone. These session controls can be useful if you log into Facebook from a friend's phone or computer and then forget to sign out. From your Account Settings, you can check if you're still logged in on other devices and remotely log out."
Businesses that use Facebook should put these controls to use to monitor and protect the integrity of the account, and guard against data leakage and reputation damage that might result from a Facebook account compromise. IT admins should have a policy in place requiring the use of the one-time password when logging in from any remote location, and should regularly monitor account activity to identify and shutdown any rogue account logins.