How do SSN scammers know someone's name?

My friend’s mom got a scam call from a fake SSN agency with the usual “due to a problem with suspicious activity your social security number is canceled” and when she pressed 1 to get connected with an agent, the scammer said “Hi is this X?” and she freaked out so she hung up.

Scammers usually buy bulk packs of phone numbers from other scammers who buy the information from crappy companies. These bulk data packs will sometimes have info like, name, address, or even ssn numbers. Likely he only had her name but that is probably how he got it.