Security News > 2023 > May > Microsoft issues optional fix for Secure Boot zero-day used by 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.
"To protect against this attack, a fix for the Windows boot manager is included in the May 9, 2023, security update release, but disabled by default and will not provide protections," the company said.
To determine if Secure Boot protections are enabled on your system, you can run the msinfo32 command from a Windows command prompt to open the System Information app.
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."
"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.
News URL
Related news
- Microsoft Teams tactics, malware connect Black Basta, Cactus ransomware (source)
- Microsoft admits GitHub hosted malware that infected almost a million devices (source)
- Microsoft March 2025 Patch Tuesday fixes 7 zero-days, 57 flaws (source)
- URGENT: Microsoft Patches 57 Security Flaws, Including 6 Actively Exploited Zero-Days (source)
- Microsoft patches Windows Kernel zero-day exploited since 2023 (source)
- Patch Tuesday: Microsoft Fixes 57 Security Flaws – Including Active Zero-Days (source)
- Microsoft: New RAT malware used for crypto theft, reconnaissance (source)
- Microsoft Trust Signing service abused to code-sign malware (source)
- Microsoft Trusted Signing service abused to code-sign malware (source)
- New Android malware uses Microsoft’s .NET MAUI to evade detection (source)
Related Vulnerability
| DATE | CVE | VULNERABILITY TITLE | RISK |
|---|---|---|---|
| 2022-01-11 | CVE-2022-21894 | Unspecified vulnerability in Microsoft products Secure Boot Security Feature Bypass Vulnerability | 0.0 |