Home Depot has confirmed that its payment systems in stores across the U.S. and Canada were breached, exposing customers' credit- and debit-card data.
The home improvement retailer did not say how many stores or customers were affected. The company has 2,266 stores with the majority in the U.S. and Canada.
The breach did not affect stores in Mexico or people who shopped online. In addition, there was no evidence that debit PINs had been compromised.
[What you need to know about the Home Depot data breach]
"We apologize for the frustration and anxiety this causes our customers, and I want to thank them for their patience and support as we work through this issue," Frank Blake, chairman and CEO of Home Depot, said in a statement released Monday. "We owe it to our customers to alert them that we now have enough evidence to confirm that a breach has indeed occurred."
Home Depot launched an investigation Sept. 2 after banks working with law enforcement notified it of a pattern of payment card fraud pointing to the retailer. The breach may have started in the spring, which is a major selling season for the company, The Wall Street Journal reported.
The company is investigating the breach with the help of the banks and law enforcement and has hired security firm Symantec and Fishnet Security.
Home Depot is the latest of a string of retailers that had payment systems compromised. Others include Neiman Marcus Group, P.F. Chang's China Bistro, Michaels, Lowe's, Supervalu, Albertsons and Target, which had 40 million debit and credit-card accounts exposed in an attack last December.
Home Depot verified the compromises a day after the blog KrebsOnSecurity reported that a variant of the BlackPOS malware used in last year's Target breach was found in Home Depot's payment systems.
The malware is designed to steal data when a card is swiped on a point-of-sale system running Microsoft Windows. First developed by a Russian teenager in 2012, BlackPOS source code is available on many underground hacking forums.
Security vendor Trend Micro reported Aug. 29 finding a new version of the malware that disguises itself as a service within antivirus software installed in the payment system. The variant also had enhancements for snatching data from the system memory of electronic cash registers.
Finding variants of effective malware that's widely available is not surprising to security researchers.
While there is no conclusive evidence that the Target and Home Depot breaches were by the same hackers, there's enough similarities that "people in the security industry are starting to feel in their bones that there's something definitely going on," Christopher Budd, threat communications manager for Trend Micro, said.
"The feeling is that this is either one group or some closely coordinated handful of groups," Budd said. "There are too many similarities for it to be completely random, uncoordinated groups."
Besides the similarities in malware, KrebsOnSecurity, which is run by former Washington Post reporter Brian Krebs, reported that payment card data stolen from Home Depot was for sale on Rescator[dot]cc, which is the same underground marketplace where Target card data was sold.
[New details suggest that Home Depot data breach is nationwide]
The string of attacks on major retailers should be a wake up call for the industry, researchers said. To tighten security, retailers have to start sharing information on breaches to help the industry plug holes in payment systems.
Trend Micro has called on retailers to set up their own information sharing and coordination center (ISAC) to counter the collaboration among hackers.
"So long as the retail industry is responding singly and in a fractured way, then the attackers are going to continue to have an advantage," Budd said.