CVE-2016-8815 in GPU Driver
Summary
by MITRE
All versions of NVIDIA Windows GPU Display Driver contain a vulnerability in the kernel mode layer (nvlddmkm.sys) handler for DxgDdiEscape where a value passed from a user to the driver is used without validation as the index to an array, leading to denial of service or potential escalation of privileges.
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Analysis
by VulDB Data Team • 07/09/2019
The vulnerability identified as CVE-2016-8815 resides within the NVIDIA Windows GPU Display Driver kernel mode layer component known as nvlddmkm.sys. This flaw specifically affects the DxgDdiEscape handler which processes escape commands from user-mode applications to communicate with the graphics driver. The vulnerability stems from inadequate input validation where user-supplied values are directly used as array indices without proper bounds checking or sanitization. This type of vulnerability falls under the category of buffer over-read conditions and represents a classic example of improper input validation that can lead to severe security implications. The flaw exists in the kernel mode driver component which operates with elevated privileges, making it particularly dangerous as it can potentially be exploited to achieve privilege escalation from user mode to kernel mode execution.
The technical implementation of this vulnerability involves the DxgDdiEscape function which serves as an interface for passing escape commands between user applications and the kernel-mode graphics driver. When a user application submits an escape command containing an index value, this value is passed directly to an internal array lookup mechanism within the kernel driver without proper validation. The lack of input sanitization means that an attacker can provide an arbitrary index value that may exceed the bounds of the intended array, potentially causing memory corruption or allowing unauthorized access to kernel memory locations. This flaw creates a pathway for attackers to manipulate the driver's internal state and potentially execute arbitrary code with kernel-level privileges. The vulnerability is particularly concerning because it operates within the kernel mode layer where security boundaries are typically most critical, and any compromise can lead to complete system control.
The operational impact of CVE-2016-8815 extends beyond simple denial of service scenarios to encompass potential privilege escalation capabilities that could allow attackers to gain complete administrative control over affected systems. While the vulnerability may initially manifest as a denial of service condition where the graphics driver crashes or becomes unresponsive, the underlying flaw in array indexing without validation opens the door to more severe exploitation techniques. Attackers could potentially craft malicious escape commands that manipulate kernel memory structures, leading to privilege escalation from user mode to kernel mode execution. This type of vulnerability is particularly dangerous in enterprise environments where graphics drivers are frequently updated and deployed across multiple systems, as a successful exploitation could compromise entire networks. The vulnerability affects all versions of NVIDIA Windows GPU Display Drivers, making it widespread and potentially impacting a large number of systems.
Mitigation strategies for CVE-2016-8815 should focus on both immediate defensive measures and long-term security improvements. The most effective immediate solution is to apply the official NVIDIA security patches and driver updates that address the specific validation issues in the DxgDdiEscape handler. System administrators should also implement additional security controls such as restricting user access to graphics driver interfaces and monitoring for unusual escape command patterns. From a defensive perspective, implementing kernel-mode exploit protection mechanisms, such as control flow integrity checks and address space layout randomization, can help prevent exploitation attempts. The vulnerability demonstrates the importance of proper input validation in kernel-mode components and aligns with common attack patterns documented in the ATT&CK framework under privilege escalation techniques. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of successful exploitation, as the vulnerability could be leveraged as a stepping stone for broader system compromise. The flaw represents a classic case where insufficient bounds checking in kernel-mode code can lead to severe security consequences, emphasizing the need for rigorous security testing and code review processes for all driver components.