CVE-2022-21815: Nvidia Cloud Gaming Guest DOS Vulnerability

CVE-2022-21815 Overview

CVE-2022-21815 is a NULL pointer dereference vulnerability in NVIDIA GPU Display Driver for Windows, specifically within the kernel mode layer (nvlddmkm.sys) handler for private IOCTLs. This vulnerability allows a local attacker with low privileges to trigger a NULL pointer dereference in the kernel through user mode code, resulting in a denial of service condition via system crash.

Critical Impact

A local attacker can cause a complete system crash (Blue Screen of Death) on affected Windows systems running vulnerable NVIDIA GPU drivers, disrupting critical operations and potentially causing data loss.

Affected Products

• NVIDIA GeForce GPU Display Driver for Windows
• NVIDIA Quadro GPU Display Driver for Windows
• NVIDIA RTX GPU Display Driver for Windows
• NVIDIA Tesla GPU Display Driver for Windows
• NVIDIA NVS GPU Display Driver for Windows
• NVIDIA Studio Driver for Windows
• NVIDIA Virtual GPU (vGPU)
• NVIDIA Cloud Gaming Guest

Discovery Timeline

• 2022-02-07 - CVE-2022-21815 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-21815

Vulnerability Analysis

This vulnerability resides in the NVIDIA kernel mode driver nvlddmkm.sys, which is a critical component responsible for managing GPU operations on Windows systems. The flaw exists in the handler for private IOCTL (Input/Output Control) operations, which are used for communication between user-mode applications and kernel-mode drivers.

The vulnerability is classified as CWE-476 (NULL Pointer Dereference), occurring when the driver fails to properly validate pointer values before dereferencing them. An attacker can craft malicious IOCTL requests from user space that cause the kernel driver to attempt to access memory through a NULL pointer, triggering an immediate system crash.

The attack requires local access to the system and low privileges, meaning an authenticated user can exploit this vulnerability without requiring administrative rights. While this vulnerability does not allow for code execution or information disclosure, the ability to reliably crash Windows systems makes it a significant denial of service threat in enterprise environments where system availability is critical.

Root Cause

The root cause of CVE-2022-21815 is improper input validation in the nvlddmkm.sys driver's private IOCTL handler. Specifically, the driver fails to verify that pointer values passed through IOCTL requests are non-NULL before dereferencing them. This lack of validation allows user-controlled data to propagate to kernel space without proper sanitization, resulting in a NULL pointer dereference when the driver attempts to access the invalid memory location.

Attack Vector

The attack vector for this vulnerability is local, requiring an attacker to have authenticated access to the target Windows system. The exploitation path involves:

1. An authenticated local user creates a malicious application that opens a handle to the NVIDIA GPU driver
2. The application sends specially crafted IOCTL requests to the driver's private IOCTL handler
3. The crafted requests contain data that causes the driver to generate a NULL pointer internally
4. When the driver attempts to dereference the NULL pointer, Windows triggers a kernel-mode exception
5. The unhandled exception results in a BSOD (Blue Screen of Death), crashing the entire system

The attack does not require user interaction beyond initial execution of the malicious application. Since the vulnerability affects kernel-mode code, the crash affects the entire operating system rather than just the malicious application.

Detection Methods for CVE-2022-21815

Indicators of Compromise

• Unexpected system crashes (BSOD) with bug check codes related to NULL pointer dereference
• Windows Event Log entries showing nvlddmkm.sys as the faulting module
• Memory dump files (MEMORY.DMP) indicating crashes originating from NVIDIA driver components
• Repeated system reboots without apparent cause on systems with NVIDIA GPUs

Detection Strategies

• Monitor Windows crash dump files for patterns involving nvlddmkm.sys driver faults
• Implement endpoint detection rules to identify processes making suspicious IOCTL calls to NVIDIA driver handles
• Deploy kernel-mode behavioral monitoring to detect anomalous driver interactions
• Use crash analysis tools to correlate BSOD events across multiple endpoints

Monitoring Recommendations

• Enable Windows Error Reporting to capture kernel crash telemetry
• Configure centralized log collection for Windows Event Logs, focusing on System and Application logs
• Implement automated alerting for multiple system crashes within short time periods
• Maintain an inventory of NVIDIA driver versions deployed across the environment for rapid vulnerability assessment

How to Mitigate CVE-2022-21815

Immediate Actions Required

• Update all affected NVIDIA GPU drivers to the latest patched versions immediately
• Inventory all Windows systems with NVIDIA GPUs to identify vulnerable driver versions
• Prioritize patching on business-critical systems and virtualization hosts using NVIDIA vGPU
• Restrict local access to sensitive systems to reduce the attack surface

Patch Information

NVIDIA has released security updates to address this vulnerability. Administrators should consult the NVIDIA Security Bulletin for specific patched driver versions for each product line. The advisory provides detailed information on affected driver versions and corresponding fixed releases for GeForce, Quadro, RTX, Tesla, NVS, Studio, Virtual GPU, and Cloud Gaming products.

Workarounds

• Limit local login access to systems with NVIDIA GPUs to trusted users only
• Implement application whitelisting to prevent unauthorized executables from running
• Monitor for and block suspicious processes attempting to interact with GPU driver interfaces
• Consider disabling non-essential NVIDIA services on critical infrastructure systems where GPU functionality is not required

# Check installed NVIDIA driver version on Windows
nvidia-smi --query-gpu=driver_version --format=csv,noheader

# View NVIDIA driver details via PowerShell
Get-WmiObject Win32_PnPSignedDriver | Where-Object {$_.DeviceName -like "*NVIDIA*"} | Select-Object DeviceName, DriverVersion

# Force update via NVIDIA GeForce Experience (if installed)
# Open GeForce Experience -> Drivers -> Check for Updates