Chick-fil-A rewards program members in D.C., Maryland and eight other states are getting letters warning that hackers may have gained access to partial payment information and other personal data during an “automated attack” on its website and app last month.

The notice also suggests that some customers had money stolen from their Chick-fil-A One accounts.

The attackers used email addresses and passwords obtained from a third-party source to gain access, Chick-fil-A said.

Its investigation of the June breach determined the hackers may have accessed information including names, gift card balances, phone numbers, addresses and the last four digits of customers’ credit card numbers, the company said.

“As soon as Chick-fil-A discovered the incident, we immediately took action to protect customers’ accounts, which included forcing log-outs of affected accounts and removing any stored payment methods,” it said in the letter.

“We also restored impacted customers’ Chick-fil-A One account balances.”

Chick-fil-A said it reset customers passwords and added rewards to affected accounts.

“Chick-fil-A continues to enhance its security, monitoring, and fraud controls as appropriate to minimize the risk of any similar incident in the future,” the company said.