Facebook removes two-factor authentication mobile numbers from search

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Facebook users who have associated a mobile phone number with their accounts in order to enable the "Login Approvals" security feature can no longer be found on the website based on those phone numbers, the company said Monday.

Facebook's search system provides reverse lookup functionality that allows users to find other people on the website by searching for their phone numbers or email addresses instead of their names.

"As we constantly iterate on our security tools to better protect our users, we have disabled the reverse lookup functionality for those using Login Approvals until we can provide new systems to make this functionality optional," a Facebook spokeswoman said Monday via email.