Canned response: The company said it brought in data security experts to investigate and contain the issue. They’re also working with federal law enforcement officials and coordinating with payment card companies to protect cardholders.

The Checkers and Rally’s chain of fast food restaurants recently discovered malware installed on point-of-sale systems at various locations scattered across the country.

The malware was designed to siphon information stored on the magnetic strip of payment cards including cardholder names, payment card numbers, card verification codes and expiration dates.

While only 15 percent of restaurants were affected, the matter is compounded by the fact that in some cases, the malware went undetected since 2015. A list of impacted locations across 20 states and their estimated dates of exposure has been posted online although the number of guests potentially impacted wasn’t shared.

Those who used a payment card at an affected restaurant during the estimated dates of exposure are encouraged to review their account statements for unauthorized charges and order a copy of their credit report. Notably, there was no mention of complementary credit monitoring service being offered to impacted customers, a perk that is often afforded to data breach victims.