CVE-2022-36337 - Insyde InsydeH2O Kernel 5. to 5.5 Stack Buffer Overflow Vulnerability in MebxConfiguration Driver

A newly discovered vulnerability dubbed CVE-2022-36337 is found to affect Insyde InsydeH2O Kernel versions 5. through 5.5. The vulnerability exists due to a stack buffer overflow issue in the MebxConfiguration driver, which can eventually lead to arbitrary code execution. This security issue is triggered when an attacker gains control over a UEFI variable under the operating system, causing the overflow to occur when read by the BIOS code.

Exploit Details

The vulnerability is caused by a lack of proper checking for the size of a UEFI variable when it is read in the MebxConfiguration driver. This can result in a stack buffer overflow, which in turn allows for arbitrary code execution.

This issue can be exploited by an attacker with local access to the system. The attacker can first overwrite the vulnerable UEFI variable and then issue a reboot, causing the BIOS to read the malicious variable's contents. The arbitrary code will then be executed with the highest level of privilege, allowing the attacker to completely compromise the system.

Here is a sample code snippet demonstrating the exploitation of the vulnerability

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

int main() {
  uint8_t malicious_uefi_variable[1024];
  
  // Overwrite the vulnerable UEFI variable with malicious data
  set_uefi_variable("MebxConfiguration", malicious_uefi_variable, sizeof(malicious_uefi_variable));
  
  // Trigger a reboot to execute the arbitrary code
  system("reboot");
  return ;
}

For more information about this vulnerability, refer to the following sources

1. CVE Details: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-36337
2. Insyde InsydeH2O Kernel: https://www.insyde.com/products/insydeh2o
3. UEFI Specifications: https://uefi.org/specifications

Mitigation

To prevent the exploitation of this vulnerability, users are advised to update their Insyde InsydeH2O Kernel to version 5.6 or later. This version includes a fix for the CVE-2022-36337 vulnerability by implementing proper buffer bounds checks in the MebxConfiguration driver, ensuring that stack buffer overflows can no longer be exploited.

Conclusion

CVE-2022-36337 poses a severe risk to users running Insyde InsydeH2O Kernel versions 5. through 5.5. An attacker can exploit this vulnerability to gain full control over the target system by executing arbitrary code with the highest level of privilege. As such, it is essential to update the system to the patched version of InsydeH2O as soon as possible to mitigate the risk associated with this vulnerability.

Timeline

Published on: 11/23/2022 03:15:00 UTC
Last modified on: 11/30/2022 15:27:00 UTC