Apple has brought on board two security researchers who previously worked to develop the infamous Thunderstrike 2 worm, which was capable of infecting a Mac's firmware.

The researchers Xeno Kovah and Corey Kallenberg, who developed the worm that targeted Macs, came over when Apple quietly purchased their firm, LegbaCore, in November 2015. However, the news went virtually unnoticed until another security researcher mentioned the acquisition during a presentation at a security conference in December 2015.

Shortly after joining Apple, Kovah tweeted that he can't disclose exactly what the duo will be doing for the tech company, but did say it will be something like “low level security” work.

A few days before the purchase, LegbaCore announced it will “not be accepting any new customer engagements.”