CVE-2021-38624: Windows Key Storage Provider Security Feature Bypass Vulnerability

Overview

Severity

Medium (CVSS 6.5)

CVSS Vector

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C

Category

Security Feature Bypass

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2021-Sep

Released

2021-09-14

Last Updated

2021-10-12

EPSS Score

0.39% (percentile: 60.2%)

FAQ

What kind of security feature could be bypassed by successfully exploiting this vulnerability? A successful attacker could bypass the Windows Key Storage Provider which issues key certificates for trust in attestation scenarios.

Affected Products (23)

Windows

• Windows 10 Version 1809 for 32-bit Systems
• Windows 10 Version 1809 for x64-based Systems
• Windows 10 Version 1809 for ARM64-based Systems
• Windows Server 2019
• Windows Server 2019 (Server Core installation)
• Windows 10 Version 1909 for 32-bit Systems
• Windows 10 Version 1909 for x64-based Systems
• Windows 10 Version 1909 for ARM64-based Systems
• Windows 10 Version 21H1 for x64-based Systems
• Windows 10 Version 21H1 for ARM64-based Systems
• Windows 10 Version 21H1 for 32-bit Systems
• Windows Server 2022
• Windows Server 2022 (Server Core installation)
• Windows 10 Version 2004 for 32-bit Systems
• Windows 10 Version 2004 for ARM64-based Systems
• Windows 10 Version 2004 for x64-based Systems
• Windows Server, version 2004 (Server Core installation)
• Windows 10 Version 20H2 for x64-based Systems
• Windows 10 Version 20H2 for 32-bit Systems
• Windows 10 Version 20H2 for ARM64-based Systems
• Windows Server, version 20H2 (Server Core Installation)
• Windows 11 version 21H2 for x64-based Systems
• Windows 11 version 21H2 for ARM64-based Systems

Security Updates (5)

• 5006672
• 5006667
• 5006670
• 5006699
• 5006674

Acknowledgments

Rafael Goncalves of Microsoft

Revision History

• 2021-09-14: Information published.
• 2021-09-23: For all CVEs affecting Windows that were released on September 14, 2021: 1) In the Security Updates table, the Build Numbers for KB KB5005565 have been corrected for all affected editions of the following versions of Windows 10: Windows 10, version 2004, all editions; Windows Server, version 2004 (Server Core installation); Windows 10, version 20H2; Windows Server, version 20H2 (Server Core Installation); Windows 10, version 21H1. 2) For CVEs where Windows Server 2022 is affected the links have been updated to point to information related to 5005575. Customers whose Windows devices are configured to receive automatic updates do not need to take any further action.
• 2021-10-12: The following revisions have been made: 1) To comprehensively address CVE-2021-38624, Microsoft has released the October 2021 Security Updates for all affected editions of Windows 10 Version 1809 and newer because these versions are also affected by CVE-2021-38624. 2) In the Security Updates table, Windows 11 for x64-based systems and Windows 11 for ARM64-based systems have been added as Windows 11 is also affected by this vulnerability. Microsoft strongly recommends that customers install the October updates to be fully protected from this vulnerability. Customers whose systems are configured to receive automatic updates do not need to take any further action.