CVE-2021-36934 : Exploit Details and Defense Strategies

A critical Windows Elevation of Privilege Vulnerability identified as CVE-2021-36934 was made public on 20th July 2021. The vulnerability impacts multiple versions of Windows 10, including Version 1809, Version 1909, Version 21H1, Version 2004, and Version 20H2, allowing attackers to execute arbitrary code with SYSTEM privileges.

Understanding CVE-2021-36934

This section delves into the detailed aspects of the Windows Elevation of Privilege Vulnerability.

What is CVE-2021-36934?

The vulnerability results from overly permissive Access Control Lists (ACLs) on critical system files, such as the Security Accounts Manager (SAM) database. An attacker exploiting this flaw could gain SYSTEM privileges, enabling them to run malicious code, install programs, access, modify, or delete data, or create new accounts with full user rights.

The Impact of CVE-2021-36934

The impact of the vulnerability is severe as it enables threat actors to execute arbitrary code with elevated privileges. Exploiting this vulnerability could lead to unauthorized system access and data manipulation.

Technical Details of CVE-2021-36934

This section provides technical insights into the CVE-2021-36934 vulnerability.

Vulnerability Description

The root cause of CVE-2021-36934 lies in the permissive ACLs assigned to critical system files, including the SAM database. The flaw allows attackers to gain unauthorized access and execute code with heightened privileges.

Affected Systems and Versions

Versions of Windows 10, such as Version 1809, Version 1909, Version 21H1, Version 2004, and Version 20H2, are affected by this security vulnerability due to insufficient ACL restrictions.

Exploitation Mechanism

To exploit this vulnerability, an attacker must first execute malicious code on the target system. Successful exploitation grants the attacker SYSTEM-level access, enabling them to perform unauthorized actions.

Mitigation and Prevention

This section covers the necessary steps to mitigate and prevent attacks leveraging CVE-2021-36934.

Immediate Steps to Take

After applying the security update, users must manually delete all shadow copies of system files, including the SAM database. It's crucial to note that solely installing the security update is insufficient to fully mitigate the vulnerability.

Long-Term Security Practices

Implementing stringent security measures, such as regular system updates, network segmentation, and access control, can help enhance overall security posture and prevent similar vulnerabilities.

Patching and Updates

Regularly applying security patches provided by Microsoft is vital to address known vulnerabilities and strengthen the security of Windows 10 systems.