Company officials found out about it last Thursday and contacted the FBI. Raley's owns Nob Hill, Bel Air and Food Source. So far, Raley's has not discovered any unauthorized transactions.
"We do know that we were the target of an attack. We just don't know at this time if it was successful, so we want people to be aware," said Raley's spokesperson Nicole Townsend.
The grocery chain said it has stepped up its security measures and contacted the FBI.
Raley's has a customer service team to assist with any questions: contact 1-800-925-9989 7 a.m. to 10 p.m.