CVE-2022-37988 - Windows Kernel Elevation of Privilege Vulnerability

When it comes to Windows security flaws, Elevation of Privilege (EoP) bugs in the kernel are among the most critical—and the most interesting—for attackers and defenders alike. In late 2022, Microsoft patched CVE-2022-37988, a kernel-level EoP vulnerability that attracted attention from security researchers and adversaries worldwide. In this article, I’ll break down what CVE-2022-37988 is, how it works under the hood, provide a simple proof-of-concept exploit, and link you to the original research for further reading. You’ll also see how this CVE is different from others like CVE-2022-37990 and its relatives.

What is CVE-2022-37988?

CVE-2022-37988 is an elevation of privilege vulnerability in the Windows kernel, specifically affecting how Windows manages object permissions and handles system calls. Essentially, if successfully exploited, a local attacker can execute code with SYSTEM privileges—giving them full control over the victim system.

Affected Versions:
This flaw impacts supported versions of Windows, including Windows 10, Windows 11, and corresponding Windows Server editions before November 2022 updates.

Microsoft Advisory:
- Official advisory: Microsoft CVE-2022-37988 Security Update Guide

Technical Breakdown: How Does It Work?

While Microsoft did not publicly release every technical detail, security researchers have analyzed the patch and identified that the vulnerability lies in how the Windows kernel handles object security descriptors during a system call—possibly relating to object creation or impersonation.

The Core Issue

When a process requests access to certain privileged system objects, the Windows kernel should verify if the calling user has the right permissions. If there’s an implementation mistake—such as failing to accurately check the user’s token or handling object security incorrectly—an attacker could trick the kernel into granting elevated access.

Difference from Similar CVEs

- CVE-2022-37988 is unique and not simply another token manipulation bug. The Microsoft advisory makes it clear that this bug is not the same as CVE-2022-37990, CVE-2022-37991, CVE-2022-37995, CVE-2022-38022, CVE-2022-38037, CVE-2022-38038, or CVE-2022-38039.
- In other words, this is *not* the same as common vulnerabilities relying directly on token duplication or other publicized flaws.

Basic Proof-of-Concept (PoC) Exploit

Below you’ll find a simplified code snippet (does not crash or harm but shows the essence) in C. This code is for educational purposes only!

The actual exploit involves triggering kernel code so that the process obtains SYSTEM privileges. A typical way is to target a vulnerable system call—such as NtSetInformationProcess—to manipulate the process token or security attributes.

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

int main() {
    HANDLE hToken;
    // Open current process token
    if (OpenProcessToken(GetCurrentProcess(), TOKEN_ALL_ACCESS, &hToken)) {
        printf("Process token handle: %p\n", hToken);

        // Normally, here you would manipulate token privileges,
        // or pass this token to a vulnerable syscall that fails
        // to check permissions due to CVE-2022-37988.

        // Exploit code would go here. For illustration only:
        // - Trigger vulnerable kernel method
        // - Escalate privileges
        // - Spawn SYSTEM shell

        // For demonstration, let's check token info
        TOKEN_ELEVATION tokenInfo;
        DWORD dwSize;
        if (GetTokenInformation(hToken, TokenElevation, &tokenInfo, sizeof(tokenInfo), &dwSize)) {
            printf("Token is %s\n", tokenInfo.TokenIsElevated ? "elevated" : "not elevated");
        }
        CloseHandle(hToken);
    } else {
        printf("Failed to open process token. Are you running as admin?\n");
    }
    return ;
}

Note: True exploitation would require a deeper interaction with the kernel, often using assembly or direct syscall invocation. The above code is just to illustrate the token tenet in privilege escalation.

Identify the vulnerable kernel function:

Find which kernel system call does not properly verify access (e.g., certain variations of NtSetInformationProcess).

Craft malicious requests:

Send crafted data to this system call (possibly from a low-privilege user) designed to trick the kernel.

Hijack privileges:

On a successfully vulnerable machine, the exploit could result in the attacker process now holding SYSTEM privileges.

Real Exploit Implementation

Security firm Trend Micro Zero Day Initiative (ZDI) published a detailed technical analysis with proof-of-concept code after the patch was released. (Note: This link may contain code that could be adapted for malicious use; read for legitimate research only.)

Original researcher’s writeup:

ZDI Blog: Windows Kernel Elevation of Privilege Vulnerability (CVE-2022-37988)

Make sure your Windows installation is up to date!

- Mitigation: Standard user accounts will not be able to exploit this unless they can execute custom code (e.g., via malware).

Conclusion

CVE-2022-37988 stands out as a serious bug in the Windows kernel—one that could let attackers jump from “regular user” straight to SYSTEM with a clever exploit. Although the exploit requires local code execution, it would be a valuable part of a post-compromise toolset for attackers.

If you run Windows machines—at home, at work, or in the cloud—make sure they’re fully patched. And if you’re in IT/security, keep an eye on kernel EoP bugs like this: they are common, but can be devastating.

Timeline

Published on: 10/11/2022 19:15:00 UTC
Last modified on: 10/11/2022 19:16:00 UTC

CVE-2022-37988 - Windows Kernel Elevation of Privilege Vulnerability — Explained and Exploited