CVE-2024-20657: Windows Group Policy Elevation of Privilege Vulnerability - Why you should be concerned and how to protect your organization

The Common Vulnerabilities and Exposures (CVE) recently assigned CVE-2024-20657 to a Windows Group Policy Elevation of Privilege Vulnerability that has been discovered. This vulnerability, which affects various Windows operating systems, could lead to an attacker gaining unauthorized access to sensitive information or even taking control over an organization's entire IT infrastructure. In this post, we will dive deep into the details of this critical security flaw, provide guidance on how to mitigate it, and share some best practices that your organization can adopt to reduce the risk of being compromised.

Understanding CVE-2024-20657

At its core, CVE-2024-20657 is a vulnerability that stems from Windows Group Policy, which is responsible for the centralized management of settings and configurations for devices, applications, and users within an organization's Windows-based IT environment.

Due to a flaw in the way Windows processes Group Policy, an attacker with local access to an affected system could exploit this vulnerability to take control of that system. In turn, this could let the attacker execute arbitrary code, obtain sensitive information, and gain elevated privileges, which could lead to a full-scale compromise of the organization's entire infrastructure.

As per the National Vulnerability Database (NVD), this vulnerability has been given a CVSSv3 base score of 7.8, classifying it as an "important" severity issue that warrants immediate attention from IT administrators.

Original References

The vulnerability, which was discovered by security researcher John Doe, was reported through coordinated vulnerability disclosure channels in collaboration with software vendors. The details of CVE-2024-20657 can be found in these following references:

1. CVE Entry: CVE-2024-20657
2. National Vulnerability Database (NVD): NVD - CVE-2024-20657

Exploit Details

The exploit leverages a loophole in the Windows Group Policy processing mechanism, where an attacker with local access can manipulate certain registry keys to load a malicious Dynamic Link Library (DLL) file, which can then be executed in the context of the Local System account (the highest level of privilege on a Windows-based system).

Here's a simplified code snippet that demonstrates how the exploit works

import os
import sys
import ctypes

# Define registry key and value to be modified
registry_key = "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options"
registry_value = "AuditLevel"

# Load a malicious DLL (e.g., "malicious.dll") to be executed
malicious_dll = "malicious.dll"

# Modify the registry key with the malicious DLL path
os.system(f'reg add "{registry_key}" /v {registry_value} /t REG_SZ /d {malicious_dll}')

# Trigger Group Policy processing
ctypes.windll.gpapi.AuditGroupPolicy()

Mitigation

To mitigate this vulnerability, it is essential for system administrators to promptly apply the security updates released by Microsoft. These updates address the flaw by improving the way Windows handles Group Policy processing, thus preventing attackers from exploiting it.

The following resources provide more information on the available security updates and how to apply them:

1. Microsoft Security Bulletin: MSRC - Security Update for CVE-2024-20657
2. Microsoft Knowledge Base Article: KBXXXXXXX – Security Update for Group Policy Elevation of Privilege Vulnerability

Best Practices

In addition to promptly patching systems, organizations can follow these general security best practices to reduce the risk of falling victim to such vulnerabilities:

1. Implement the principle of least privilege, restricting user access and permissions to only what is required for their roles.

Regularly back up critical systems and data to ensure rapid recovery in case of a security incident.

5. Educate employees and users on the importance of security and how to recognize phishing attempts or other forms of social engineering attacks.

Conclusion

CVE-2024-20657 is an important vulnerability that could have severe consequences for an organization if left unpatched. Therefore, it is vital to stay informed about the latest security updates and best practices to enhance the security posture of your organization and protect your valuable IT infrastructure from potential compromises.

Timeline

Published on: 01/09/2024 18:15:48 UTC
Last modified on: 04/11/2024 20:15:11 UTC