#VU54835 Security features bypass in Windows and Windows Server - CVE-2021-33781

Vulnerability identifier: #VU54835

Vulnerability risk: Medium

CVSSv4.0: 6.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-33781

CWE-ID: CWE-254

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Windows
Operating systems & Components / Operating system
Windows Server
Operating systems & Components / Operating system

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to security feature bypass issue in Active Directory. A remote authenticated attacker can gain elevated privileges on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Windows: 10 20H2 10.0.19042.572, 10 21H1 10.0.19043.985, 10 1511 10.0.10586.3, 10 1607 10.0.14393.10, 10 1703 10.0.15063.138, 10 1709 10.0.16299.19, 10 1803 10.0.17134.48, 10 1809 10.0.17763.1, 10 1909 10.0.18363.476, 10 2004 10.0.19041.264

Windows Server: 2019 10.0.17763.1 - 2019 2004

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External links
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33781

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.