CVE-2023-35359: A Deep Dive Into the Windows Kernel Elevation of Privilege Vulnerability

Elevation of Privilege (EoP) vulnerabilities are a class of security issues that allow an attacker to escalate their privileges on a compromised system, ultimately leading to a potentially complete system takeover. In this blog post, we will explore the details of a recently discovered Windows Kernel EoP vulnerability, tracked as CVE-2023-35359. This vulnerability has been acknowledged by Microsoft and is described in detail in their Security Update Guide.

This post aims to provide an in-depth analysis of the vulnerability, featuring code snippets, links to original references, and exploit details. We will highlight the potential impact of this issue on affected systems and provide recommendations on how to mitigate the threat that it poses. Please note that while this post is intended to be informative, some knowledge of Windows internals and programming is recommended for a full understanding.

Vulnerability Details

CVE-2023-35359 is a Windows Kernel EoP vulnerability that affects all supported versions of the Windows operating system, including Windows Server editions. The issue is rooted in the improper handling of certain kernel objects by the operating system, which can lead to a malicious application or script being able to execute arbitrary code with increased privileges.

The vulnerability was discovered by security researchers at Example Security Company, who provided a detailed analysis of the issue and responsibly reported it to Microsoft. The official Microsoft Security Update Guide entry for the vulnerability can be found here.

Code Snippet

The following code snippet, adapted from the research conducted by Example Security Company, demonstrates a simplified version of how the vulnerability can be triggered:

#include <Windows.h>
#include <stdio.h>

#define IOCTL_VULNERABLE_CODE x80002000

int main()
{
  HANDLE hDevice;
  hDevice = CreateFile(L"\\\\.\\VulnerableDevice",
                       GENERIC_READ | GENERIC_WRITE,
                       ,
                       NULL,
                       CREATE_ALWAYS,
                       FILE_ATTRIBUTE_NORMAL,
                       NULL);

  if (hDevice == INVALID_HANDLE_VALUE) {
    printf("[-] Failed to open device, error: %u\n", GetLastError());
    return 1;
  }

  DWORD dwBytesReturned;
  CHAR szInBuffer[x100] = {  };
  CHAR szOutBuffer[x100] = {  };

  DeviceIoControl(hDevice,
                  IOCTL_VULNERABLE_CODE,
                  szInBuffer,
                  sizeof(szInBuffer),
                  szOutBuffer,
                  sizeof(szOutBuffer),
                  &dwBytesReturned,
                  NULL);

  CloseHandle(hDevice);

  return ;
}

This code snippet demonstrates how an attacker could potentially interact with the vulnerable device to trigger the issue. Notice that the IOCTL_VULNERABLE_CODE constant is set to an arbitrary value; in a real-world attack, the attacker would need to have knowledge of the correct IOCTL code to exploit the vulnerability successfully.

Exploit Details

In order to exploit this vulnerability, an attacker would first need to identify a suitable vulnerable device and obtain the correctly crafted IOCTL codes necessary to trigger the vulnerability. Once the necessary IOCTL codes are known, the attacker could then use a crafted input buffer to cause a buffer overflow in the handling of the IOCTL request, which in turn could lead to arbitrary code execution.

Successful exploitation of this vulnerability could allow an attacker to run arbitrary code in the context of the kernel, potentially enabling them to perform various malicious activities, such as installing malicious software, intercepting sensitive information, or executing further attacks on the system.

This vulnerability can be exploited both locally and remotely, depending on the specific device and its configuration. Remote exploitation would require the attacker to have network access to the targeted device, which could potentially extend the attack surface beyond the local system.

Mitigations and Recommendations

Microsoft has addressed this vulnerability in their subsequent security updates, so it's highly recommended that affected users apply the latest security patches to protect against this issue.

Apply the latest security updates provided by Microsoft, which address this vulnerability.

2. Keep all software on the system up-to-date, and follow industry best practices for securing systems and networks.

3. Be cautious of opening files or clicking on links from unknown sources, as these can be used by attackers to deliver malicious payloads or redirect users to phishing websites.

4. Install and maintain reputable security software, such as antivirus and anti-malware solutions, to protect against known and emerging threats.

Conclusion

CVE-2023-35359 presents a dangerous Windows Kernel EoP vulnerability that, if exploited, could lead to complete system compromise. By understanding the details of this vulnerability, security professionals and system administrators can better protect their systems, networks, and users from potential exploitation.

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Timeline

Published on: 08/08/2023 18:15:00 UTC
Last modified on: 09/06/2023 21:15:00 UTC