A researcher has developed a downgrade attack that can make Windows machines covertly, persistently and irreversibly vulnerable, even if they were fully patched before that. A downgrade attack exploiting the Windows Update process The direction of SafeBreach researcher Alon Leviev’s probing was inspired by the BlackLotus UEFI bootkit, which was able to bypass the UEFI Secure Boot by exploiting a vulnerability, as well as disable Windows security mechanisms (e.g., BitLocker, HVCI, and Windows Defender) and persist on compromised machines.

Source: Help Net Security