Last week, we learned that the security breach that hit Target during the holiday season was much more severe than previously believed. An internal investigation concluded that hackers have gotten away with financial information, phone numbers and email addresses belonging to as many as 110 million customers – a cyber theft of historical proportions. But now, it appears as if the incident was a part of an even broader series of attacks against not one but several major retailers.

At least three other “well-known U.S. retailers” suffered data breaches in the same time frame the Target incident took place, anonymous sources familiar with the matter told the media. The hackers reportedly employed similar tools and techniques but weren’t nearly as successful, only compromising a relatively small amount of user data. Each time, they used a RAM scraper to steal credit card numbers before they were encrypted by the point-of-sale devices. The technology has been around for years, and Visa warned retail companies to stay vigilant against this kind of attacks, but the assailants still managed to catch the industry off guard.

“It was not clear whether Target’s security team had implemented the measures that Visa had recommended to mitigate the risks of being attacked,” Reuters reported. “Yet a law enforcement source familiar with the breach said that even if the retailer had implemented those steps, the efforts may not have succeeded in stopping the attack. That is because the attackers were more sophisticated than the ones in the previous attacks described in the Visa alerts, according to the source.”

Hackers armed with cutting edge memory parsing malware are not the only threat to consumer privacy. New reports suggest that the NSA posses the capability to target computers even when they are not connected to the internet using miniature radio transmitters.