CVE-2019-5670 in Windows GPU Display Driver
Summary
by MITRE
NVIDIA Windows GPU Display Driver contains a vulnerability in the kernel mode layer handler for DxgkDdiEscape in which the software uses a sequential operation to read from or write to a buffer, but it uses an incorrect length value that causes it to access memory that is outside of the bounds of the buffer which may lead to denial of service, escalation of privileges, code execution or information disclosure.
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Analysis
by VulDB Data Team • 05/13/2020
The vulnerability identified as CVE-2019-5670 resides within the NVIDIA Windows GPU Display Driver kernel mode layer, specifically within the DxgkDdiEscape handler functionality. This flaw represents a classic buffer overflow condition that occurs when the driver processes escape commands sent from user-mode applications to the kernel-mode display driver interface. The vulnerability stems from improper validation of buffer lengths during kernel-mode operations, creating a scenario where malicious inputs can cause the driver to access memory outside the intended buffer boundaries. The affected component operates at the kernel level, making it particularly dangerous as it can directly interact with system memory and hardware resources without typical user-mode protections.
The technical implementation of this vulnerability involves a sequential buffer operation pattern where the driver reads or writes data to memory locations using incorrect length parameters. This misconfiguration allows an attacker to manipulate the buffer access operations through crafted escape commands that are processed by the DxgkDdiEscape function. The flaw falls under the category of buffer overflow vulnerabilities as defined by CWE-121, specifically manifesting as a heap-based buffer overflow when the driver fails to properly validate the size of input data before processing. The vulnerability is particularly concerning because it operates within the kernel mode context, where it can bypass standard operating system security mechanisms and directly interact with critical system resources.
The operational impact of CVE-2019-5670 extends across multiple security domains including privilege escalation, denial of service, code execution, and information disclosure. An attacker with local system access can potentially leverage this vulnerability to elevate privileges from standard user to system-level access, effectively compromising the entire system. The denial of service aspect can be exploited to crash the graphics driver or entire system, while code execution capabilities allow for arbitrary code implantation within the kernel context. Information disclosure vulnerabilities may enable attackers to read sensitive kernel memory, potentially exposing system credentials, encryption keys, or other confidential data. This vulnerability directly maps to ATT&CK technique T1068 which covers local privilege escalation and T1499 which encompasses network denial of service attacks through kernel-level manipulation.
Mitigation strategies for this vulnerability require immediate patch deployment from NVIDIA, as the primary fix involves correcting the buffer length validation within the DxgkDdiEscape handler. System administrators should prioritize updating to the latest NVIDIA GPU driver versions that contain the patched kernel mode components. Additional protective measures include implementing kernel-mode exploit prevention mechanisms such as kernel address space layout randomization, data execution prevention, and controlling access to graphics driver interfaces. Network segmentation and privilege restriction can help limit potential attack vectors, while monitoring for suspicious graphics driver activity can aid in early detection of exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation in kernel-mode drivers and highlights the need for comprehensive security testing of graphics driver components, particularly those handling user-supplied escape commands. Organizations should also consider implementing application whitelisting policies that restrict execution of unauthorized graphics-related applications that might attempt to exploit this vulnerability.