Most computers firmware can store a Windows executable. Microsoft pushed for an addition to the ACPI tables called WPBT. That stores a Windows exectuable in the firmware. It is of course totally used for the intended purpose…
I’m always dismayed but not surprised by how many people don’t know about Windows Platform Binary Table, which has existed since Windows 8. It’s not exactly the type of feature that Microsoft or the board vendors would want to publicize, seeing as it gives them persistent rootkit capabilities on the same level as UEFI rootkits.
Most normal people’s model of Windows security is “if something goes wrong then I wipe the disk and reinstall Windows,” and WPBT completely breaks that model, and has been doing so for 12 years.
Thankfully there are ways to disable it:
