Vulnerability identifier: #VU58953

Vulnerability risk: High

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-43217

CWE-ID: CWE-787

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 compromise vulnerable system.

The vulnerability exists due to a boundary error when processing untrusted input in Windows Encrypting File System (EFS). A remote attacker can trigger out-of-bounds write and execute arbitrary code on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Windows: 10 1809 10.0.17763.1, 10 1909 10.0.18363.476, 10 2004 10.0.19041.264, 10 20H2 10.0.19042.572, 10 1607 10.0.14393.10, 7, 8.1 - 8.1 RT, 10 21H1 10.0.19043.985, 11 21H2 10.0.22000.194, 10 21H2 10.0.19044.1288, 10 1507 10.0.10240.16405, 10 1903 10.0.18362.116, 10 1803 10.0.17134.48, 10 1709 10.0.16299.19, 10 1703 10.0.15063.138, 10 1511 10.0.10586.3

Windows Server: 2008 - 2019 2004

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External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43217

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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