According to Ars Technica, Windows computers that had received all available patches were still compromised by a UEFI bootkit called BlackX. Ars Technica reported that the bootkit works by taking advantage of uncertainty surrounding how Microsoft defines and communicates its Secure Boot protections. The report also examined whether Microsoft bears responsibility for leaving those protections unclear, a question raised in the outlet's coverage of the infections.

Source: Ars Technica.