Then the user can change the setting to "friends," "friends except acquaintances" or, the most restrictive, "only me."
The user then needs to go to the privacy settings, and click on ‘how you connect.’
Then under "who can look you up using the email address or phone number you provided," select "friends" or "friends of friends,” the report said.
But the most easy and simple way to shield your phone number from Facebook, is to remove it from the social networking site, it added.
According to the report, Facebook has restricted phone number searches on its mobile site after a security researcher was able to find Facebook users by searching random phone numbers.
Facebook has also said that being able to look someone up by searching for their phone number on the site is a feature, not a bug.