Late last year, Target received a whirlwind of negative press when its pay terminals were infected by a malware program that stole customer data and credit card information. The malware, which hit Target during the peak shopping time of Black Friday weekend, ultimately managed to steal about 40 million credit card numbers, as well as additional personal data for 70 million customers.

Eventually, Target replaced its payment terminals and credit card companies replaced cards for most customers, effectively ending the malware scare. Or so we thought. Fast forward to now, and the Department of Homeland Security is warning that the malware may have infected more than 1,000 other businesses in the U.S. without their knowledge.

The Department of Homeland Security warnings were the subject of a recent Tech Times report, which says that the malware program – which has been dubbed “Backoff,” after a word that security engineers found in the software’s coding – makes its way covertly through corporate networks before finding and infecting cash register systems. Once there, the malware can set up shop and easily steal credit card numbers and other personal information. Worst of all, it can do so without being detected.

Part of the problem is that, until very recently, Backoff has not been identifiable to antivirus software. Recent software updates have revamped their definitions to include the malware, but since not all businesses are using the most up-to-date antivirus programs, many could still be missing the infection.

The other problem is that credit card information is simply too easy to steal. The Tech Times article highlights the weakness of magnetic stripes, which are still used on all American credit cards despite being “an antiquated technology from the 1960s.” As long as American customers are using cards with magnetic stripes, hackers will have little difficulty accessing their data.

Target, driven by its own disastrous fight with the Backoff malware, is playing its part in reducing the reliance on magnetic stripes. The department store chain is revamping payment systems to include Europay-Mastercard-Visa, a payment method used in Europe that uses chip-based cards instead of magnetic-based ones. Supposedly, the pay method is significantly more secure than American magnetic stripe credit cards.