C1SOC Advisory: Elevation of Privilege Vulnerability CVE-2024-21338 in Windows Kernel

Windows Kernel

Table of Contents

  • Overview of the Threat
  • Technical Details of the Vulnerability
  • Exploitation Methodology
  • Implications and Impact
  • Countermeasures and Recommendations
  • Conclusion
  • References
  • Contact Us

Overview of the Threat 

The notorious Lazarus Group, associated with North Korean state interests, has recently exploited a zero-day vulnerability in the Windows Kernel, marked as CVE-2024-21338, to gain kernel-level access on compromised systems. This exploit grants them elevated privileges, enabling them to disable security software and perform other malicious activities.

Technical Details of the Vulnerability

  • CVE ID: CVE-2024-21338
  • CVSS Score: 7.8 (High)
  • Description: The vulnerability allows attackers to gain SYSTEM privileges by exploiting a flaw in the Windows Kernel.
  • Affected Systems: Windows 10, version 1703 (RS2/15063) and possibly others.

Exploitation Methodology

The Lazarus Group utilized a specially crafted application to exploit CVE-2024-21338, allowing them to take control of affected systems. This exploit involves manipulating the appid.sys driver, a component critical for the functioning of Windows AppLocker, thereby bypassing all security checks and running the FudModule rootkit.

Implications and Impact

  • Escalated Privileges: The exploit grants attackers SYSTEM privileges, providing them with extensive control over compromised systems.
  • Disabling Security Software: The FudModule rootkit deployed by Lazarus Group can disable various security solutions, including AhnLab V3 Endpoint Security, CrowdStrike Falcon, HitmanPro, and Microsoft Defender Antivirus.

Countermeasures and Recommendations

  • Apply Security Updates: Ensure that all systems are updated with the latest patches from Microsoft to mitigate the vulnerability.
  • Enhance Monitoring: Implement robust monitoring solutions to detect and respond to suspicious activities promptly.
  • Security Awareness: Educate users about phishing attacks and suspicious software installations to prevent initial system compromise.


The exploitation of CVE-2024-21338 by the Lazarus Group underscores the evolving threat landscape posed by sophisticated threat actors. Organizations must remain vigilant, implement necessary security measures, and stay informed about emerging threats to safeguard against such attacks.


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