Retail giant Kmart, a Sears company, detected a payment data systems breach on Thursday, and the company says initial investigations reveal the breach started in early September.

According to the company, which is working with third-party security experts, the store payment data systems were infected with a form of malware that went undetected by anti-virus systems. Kmart says it was able to remove the malware, but certain debit and credit card numbers stand compromised.

[Image courtesy: Kmart]