"While the forensic and criminal investigations are ongoing, we know that malicious software (malware) was clandestinely installed on our system," stated company CEO Karen Katz.
"It appears that the malware actively attempted to collect or 'scrape' payment card data from July 16, 2013 to October 30, 2013. During those months, approximately 1,100,000 customer payment cards could have been potentially visible to the malware. To date, Visa, MasterCard and Discover have notified us that approximately 2,400 unique customer payment cards used at Neiman Marcus and Last Call stores were subsequently used fraudulently."
The company has begun notifying potentially affected customers for whom they have addresses or email and who shopped with them between January 2013 and January 2014, and offering one free year of credit monitoring and identity theft protection.
They also urged their customers to check their payment card statements for suspicious activities, and reassured them that if they are reported in a timely manner, the credit card companies will reimburse the money they lost.
They made sure to note that customers who shopped online don't seem to be affected, and that PINs, social security numbers and birth dates weren't compromised.
An indication that the company might have suffered a breach came in mid-December, when their merchant processor notified them of unauthorized payment card activity following customer purchases at one of their stores.
The breach was confirmed on January 1, by a forensic firm they hired.
"Based upon the information we have to date, it appears that sophisticated, self-concealing malware, capable of fraudulently obtaining payment card information, was active between July 16 and October 30, 2013," they stated, but said that they aren't aware of any connection between their and the Target breach (although other sources say that the malware used in both breaches appears to be the same).
Finally, they added that they have taken a number of steps to contain the situation and to improve their security measures.