Security News > 2023 > May > Microsoft fixes Secure Boot zero-day used by BlackLotus UEFI malware
Microsoft has released security updates to address a Secure Boot zero-day vulnerability exploited by BlackLotus UEFI malware to infect fully patched Windows systems.
According to a Microsoft Security Response Center blog post, the security flaw was used to bypass patches released for CVE-2022-21894, another Secure Boot bug abused in BlackLotus attacks last year.
"Microsoft is releasing CVE-2023-24932, and associated configuration guidance, to address a Secure Boot bypass vulnerability used by the BlackLotus bootkit to exploit CVE-2022-21894," the company said.
Secure Boot is toggled on if you see a "Secure Boot State ON" message on the left side of the window after selecting "System Summary."
While the security updates released today by Redmond contain a Windows boot manager fix, they are disabled by default and will not remove the attack vector exploited in BlackLotus attacks.
"Once the mitigation for this issue is enabled on a device, meaning the revocations have been applied, it cannot be reverted if you continue to use Secure Boot on that device," Microsoft said.
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Related Vulnerability
| DATE | CVE | VULNERABILITY TITLE | RISK |
|---|---|---|---|
| 2023-05-09 | CVE-2023-24932 | Unspecified vulnerability in Microsoft products Secure Boot Security Feature Bypass Vulnerability | 0.0 |
| 2022-01-11 | CVE-2022-21894 | Unspecified vulnerability in Microsoft products Secure Boot Security Feature Bypass Vulnerability | 0.0 |