Glupteba, an advanced piece of malware, has been used in several cybercriminal attacks for more than a decade now. But Palo Alto's Unit 42 only brought to light one of the features that made it so effective - its Unified Extensible Firmware Interface (UEFI) bootkit component, which allowed it to intervene and control the operating system (OS) boot process and be extremely difficult to detect and remove, last November 2023.