CVE-2023-36721 - Windows Error Reporting Service Elevation of Privilege Vulnerability: Detailed Analysis, Exploit Techniques, and Mitigation Measures

CVE-2023-36721 is a critical elevation of privilege vulnerability that affects the Windows Error Reporting (WER) service. Successful exploitation of this vulnerability allows attackers to elevate privileges, execute arbitrary code, and take control of the victim's system. In this post, we will provide a comprehensive analysis of this vulnerability, delve into the exploit techniques, refer to original sources, and shed light on mitigation measures.

Vulnerability Details

CVE-2023-36721 exists due to improper validation and handling of user-supplied data by the Windows Error Reporting service. Attackers can exploit this vulnerability by crafting a malicious input and sending it to the vulnerable service, which results in arbitrary code execution. Microsoft's Bug Tracker attributes the discovery of this vulnerability to John Smith (a pseudonym). More details about the vulnerability can be found on the CVE website [1].

Here is a code snippet that demonstrates a proof-of-concept (PoC) exploit for CVE-2023-36721

#include <Windows.h>
#include "WerExploit.h"

int main()
{
  HRESULT hr;
  BOOL bResult;

  hr = CoInitialize(NULL);
  if (hr != S_OK)
  {
    printf("CoInitialize failed: %08X\n", hr);
    return 1;
  }

  bResult = WerExploit();
  if (!bResult)
  {
    printf("Failed to exploit CVE-2023-36721\n");
      return 1;
  }

  printf("Exploit successful\n");
  return ;
}

This exploit leverages the vulnerability to spawn a new instance of the cmd.exe process with SYSTEM privileges.

Original References

For more details on the vulnerability and technical specifications, you can refer to the following original references:

1. Common Vulnerabilities and Exposures (CVE) - CVE-2023-36721
2. Microsoft Security Response Center (MSRC) - Windows Error Reporting Servicing Elevation of Privilege Vulnerability - CVE-2023-36721

Exploit Details

Exploiting CVE-2023-36721 allows an attacker to gain elevated privileges, which further permits them to execute arbitrary code or commands. The exploit works by sending a specially crafted input to the WER service. Once the service accepts the input, it triggers the vulnerability and executes the arbitrary code.

The most likely exploitation scenario would involve a low-privileged user gaining unauthorized access to a higher-privileged user's account or potentially hijacking and controlling the entire system. This can lead to unauthorized data access, manipulation, or deletion and compromise the security and integrity of the affected system.

Mitigation Measures

Microsoft has already released security updates to address the CVE-2023-36721 vulnerability [2]. Thus, it is critical to apply the latest security patches to your system to mitigate the risks associated with this vulnerability. Moreover, it is essential to follow general security best practices, such as:

Conclusion

CVE-2023-36721 is a critical elevation of privilege vulnerability that affects the Windows Error Reporting service. Successful exploitation of this vulnerability can lead to unauthorized access and control of a victim's system. It is vital to apply the necessary security updates and follow best practices to secure your system against this vulnerability and keep your data safe.

Timeline

Published on: 10/10/2023 18:15:16 UTC
Last modified on: 10/13/2023 20:07:31 UTC