Cell phone numbers are becoming increasingly common for providing additional security.

A process called two-factor authentication means that you will receive a text message with a unique one-time-use code that allows you to log in. It’s especially handy for very sensitive accounts, like a mobile payment app or online banking, as it means a thief who gains access to your username and password would also need access to your smartphone in order to get into your account.

There are less sensitive accounts that can also ask for your cell phone number in order to provide additional security, but as one researcher has discovered, this could be problematic. Given that people might change their cell phone numbers from time to time, as in when they change jobs or move their service to another carrier, your old cell phone number might still be linked to your Facebook account. When someone else ends up with that phone number, they may receive alerts and notifications from Facebook about your account.

If they attempt to use your old phone number with your account, they may actually be able to change your account password and log into your social media profile.

Fortunately, there is an additional step you can take to prevent this type of account takeover. For any account that offers you the option to link a phone number to your login, make sure you update your phone number if you get a new number. Once you’ve done that, activate your notifications to alert you to any changes or logins on your account. If you enable these notifications on Facebook, you will be alerted if someone tries to log into your account, change your password, or makes any other changes in your profile.

Account security is a growing problem, but changing your passwords routinely and auditing your account profiles to stay aware of your settings can help you maintain a measure of control over your information.

Contact the Identity Theft Resource Center for toll-free, no-cost assistance at (888) 400-5530. For on-the-go assistance, check out the free ID Theft Help App from ITRC.