CVE-2016-6915 in Video Driver
Summary
by MITRE
Stack-based buffer overflow in nvhost_job.c in the NVIDIA video driver for Android, Shield TV before OTA 3.3, Shield Table before OTA 4.4, and Shield Table TK1 before OTA 1.5.
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Analysis
by VulDB Data Team • 04/25/2017
The vulnerability identified as CVE-2016-6915 represents a critical stack-based buffer overflow within the NVIDIA video driver component known as nvhost_job.c, affecting multiple generations of NVIDIA Shield devices including the Shield TV and Shield Table series. This flaw exists in the Android-based operating systems that power these devices, specifically before certain over-the-air update releases. The vulnerability stems from improper bounds checking during the processing of job submission requests within the video driver subsystem, creating an exploitable condition that can be leveraged by malicious actors to execute arbitrary code on affected devices.
The technical implementation of this buffer overflow occurs when the nvhost_job.c component processes incoming job requests without adequate validation of input parameters. When a maliciously crafted job submission is received, the driver fails to properly verify the size of data structures being copied to stack buffers, allowing an attacker to overwrite adjacent stack memory locations. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, which is particularly dangerous because it can be exploited to overwrite return addresses, function pointers, or other critical stack data structures. The flaw is particularly concerning in the context of mobile and embedded devices where privilege escalation and code execution capabilities can lead to complete system compromise.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides potential attackers with a pathway to achieve arbitrary code execution within the privileged context of the video driver. Given that video drivers typically operate with elevated privileges and have direct access to hardware resources, successful exploitation could enable attackers to bypass normal security boundaries, access sensitive data, or install persistent backdoors. The affected devices represent a significant attack surface since they are consumer electronics that often remain connected to networks and may store personal information or provide access to other networked systems. The vulnerability affects multiple device generations and update levels, indicating that this was a widespread issue within NVIDIA's driver implementation that required coordinated patching across different product lines.
Mitigation strategies for CVE-2016-6915 should prioritize immediate deployment of available security patches and updates provided by NVIDIA for the affected Shield device models. Organizations and users must ensure that all devices receive the appropriate over-the-air updates, particularly those targeting OTA 3.3 for Shield TV, OTA 4.4 for Shield Table, and OTA 1.5 for Shield Table TK1. Network administrators should implement monitoring for suspicious job submission patterns that might indicate exploitation attempts, while also ensuring that affected devices are not exposed to untrusted network environments. The vulnerability demonstrates the importance of input validation and bounds checking in kernel-level drivers, as recommended by the ATT&CK framework's defense evasion techniques that often involve leveraging driver-level vulnerabilities to avoid detection and maintain persistence. Additionally, device manufacturers should consider implementing runtime protections such as stack canaries or address space layout randomization to mitigate the impact of similar vulnerabilities that may be discovered in the future.