https://consumerist.com/2017/10/04/sonic-confirms-payment-system-attack-offers-pointless-credit-monitoring/

As we learned last week based on information from people in the banking industry, payment cards used at Sonic Drive-In locations have been linked to suspicious transactions. Sonic confirmed today that its payment systems were indeed breached in a malware attack, potentially by crooks seeking payment card numbers.

What Sonic isn’t doing is specifying the locations where this happened. In a chain with thousands of restaurants, that information would be helpful.