CVE-2021-43237: Microsoft Windows Update Assistant Link Following Local Privilege Escalation Vulnerability
First published: Tue Dec 14 2021(Updated: )
This vulnerability allows local attackers to escalate privileges on affected installations of Microsoft Windows. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. Additional user interaction is required in that an administrator must begin a version update of Windows. The specific flaw exists within Windows Update Assistant. By creating a directory junction, an attacker can abuse Windows Update Assistant to change the DACL on an arbitrary file. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of SYSTEM.
Credit: secure@microsoft.com secure@microsoft.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Microsoft Windows 10 | =20H2 | |
| Microsoft Windows 10 | =21H1 | |
| Microsoft Windows 10 | =1909 | |
| Microsoft Windows 10 | =21H2 | |
| Microsoft Windows 10 | =21H1 | |
| Microsoft Windows 10 | =1909 | |
| Microsoft Windows 10 | =1909 | |
| Microsoft Windows 10 | =21H2 | |
| Microsoft Windows 10 | =20H2 | |
| Microsoft Windows 10 | =2004 | |
| Microsoft Windows Server | =20H2 | |
| Microsoft Windows Server | =2004 | |
| Microsoft Windows 10 | =2004 | |
| Microsoft Windows 10 | =2004 | |
| Microsoft Windows 10 | =21H1 | |
| Microsoft Windows 10 | =21H2 | |
| Microsoft Windows 10 | =20H2 | |
| Microsoft Windows 10 | =20h2 | |
| Microsoft Windows 10 | =20h2 | |
| Microsoft Windows 10 | =20h2 | |
| Microsoft Windows 10 | =21h1 | |
| Microsoft Windows 10 | =21h1 | |
| Microsoft Windows 10 | =21h1 | |
| Microsoft Windows 10 | =21h2 | |
| Microsoft Windows 10 | =21h2 | |
| Microsoft Windows 10 | =21h2 | |
| Microsoft Windows 10 | =1909 | |
| Microsoft Windows 10 | =1909 | |
| Microsoft Windows 10 | =1909 | |
| Microsoft Windows 10 | =2004 | |
| Microsoft Windows 10 | =2004 | |
| Microsoft Windows 10 | =2004 | |
| Windows 11 | ||
| Windows 11 | ||
| Microsoft Windows Server | =20h2 | |
| Microsoft Windows Server | =2022 | |
| Microsoft Windows Server 2016 | =2004 | |
| Microsoft Windows | ||
| Windows 11 | =21H2 | |
| Windows 11 | =21H2 | |
| Microsoft Windows Server 2022 | ||
| Microsoft Windows Server 2022 |
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2021-43237?
CVE-2021-43237 is categorized as a privilege escalation vulnerability in Microsoft Windows.
How do I fix CVE-2021-43237?
To fix CVE-2021-43237, apply the security updates provided by Microsoft for affected Windows versions.
What systems are affected by CVE-2021-43237?
CVE-2021-43237 affects Microsoft Windows 10 versions 20H2, 21H1, 21H2 and Windows Server 2022.
What kind of attack does CVE-2021-43237 enable?
CVE-2021-43237 allows local attackers to escalate privileges on the affected Windows installations.
Is user interaction required to exploit CVE-2021-43237?
Yes, additional user interaction is required to exploit CVE-2021-43237 after gaining low-privileged access.
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