Privilege escalation in Microsoft Windows



Published: 2021-11-25 | Updated: 2021-12-14
Risk High
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2021-43890
CWE-ID CWE-264
Exploitation vector Local
Public exploit This vulnerability is being exploited in the wild.
Vulnerable software
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Windows
Operating systems & Components / Operating system

Windows Server
Operating systems & Components / Operating system

Vendor Microsoft

Security Bulletin

This security bulletin contains one high risk vulnerability.

1) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU58367

Risk: High

CVSSv3.1: 8.4 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2021-43890

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: Yes

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to incorrect permissions in windows installer service. A local user can run a specially crafted program to execute arbitrary code with SYSTEM privileges.

The vulnerability exists due to incomplete patch for #VU58061 (CVE-2021-41379).

Note, the vulnerability is being actively exploited in the wild.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Windows: 10 - 10 S

Windows Server: 2019 - 2022


CPE2.3 External links

http://github.com/klinix5/InstallerFileTakeOver
http://blog.talosintelligence.com/2021/11/attackers-exploiting-zero-day.html
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43890

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.



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