Don’t pick up the phone to answer calls from unknown numbers. Instead, let them go to voicemail.

That’s the operational security advice being promulgated to Americans by the U.S. Federal Communications Commission in response to an ongoing series of
attacks designed to trick victims into uttering a single word.

The FCC says in a March 27 alert that the scam centers
on tricking victims into saying the word “yes,” which fraudsters record and later use to attempt to make fraudulent charges on a person’s utility or
credit card accounts.

“The scam begins when a consumer answers a call and the person at the end of the line asks, ‘Can you hear me?’ The caller then records the consumer’s
‘Yes’ response and thus obtains a voice signature,” the FCC warns. “This signature can later be used by the scammers to pretend to be the consumer and
authorize fraudulent charges via telephone.”