CVE-2016-3139 in Linux
Summary
by MITRE
The wacom_probe function in drivers/input/tablet/wacom_sys.c in the Linux kernel before 3.17 allows physically proximate attackers to cause a denial of service (NULL pointer dereference and system crash) via a crafted endpoints value in a USB device descriptor.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 10/11/2024
The vulnerability identified as CVE-2016-3139 resides within the Linux kernel's USB tablet driver subsystem, specifically in the wacom_probe function located in drivers/input/tablet/wacom_sys.c. This flaw represents a classic null pointer dereference vulnerability that can be exploited by attackers who have physical proximity to the targeted system. The vulnerability affects Linux kernel versions prior to 3.17, making it a significant concern for systems running older kernel versions where the wacom tablet driver is utilized. The issue manifests when the kernel processes USB device descriptors from Wacom tablet devices, particularly when these descriptors contain crafted endpoint values that trigger unexpected behavior in the driver's probe routine.
The technical mechanism behind this vulnerability involves the wacom_probe function failing to properly validate endpoint data structures within USB device descriptors before attempting to access them. When a maliciously crafted USB device presents endpoint values that do not conform to expected formats or contain null references, the kernel's input subsystem crashes upon attempting to dereference these invalid pointers. This type of vulnerability falls under CWE-476, which specifically addresses NULL pointer dereference conditions that can lead to system instability and potential denial of service scenarios. The flaw essentially creates a path where unvalidated input from a USB device can directly translate into kernel memory access violations.
The operational impact of CVE-2016-3139 extends beyond simple system crashes, as it enables attackers with physical proximity to cause persistent denial of service conditions that can disrupt legitimate user activities. In environments where Wacom tablet devices are commonly used, such as graphic design studios, educational institutions, or corporate offices, this vulnerability could be exploited to repeatedly crash systems or render tablet functionality unusable. The attack vector is particularly concerning because it requires minimal privileges and only physical access to the device, making it accessible to adversaries who may have legitimate access to the premises but wish to cause disruption. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers network denial of service, though it operates at a lower system level through USB device manipulation rather than network protocols.
Mitigation strategies for CVE-2016-3139 primarily focus on kernel version updates, which provide the most effective solution by patching the validation logic in the wacom_probe function. System administrators should prioritize upgrading to Linux kernel version 3.17 or later, where the vulnerability has been addressed through improved input validation of USB device descriptors. Additionally, implementing USB device whitelisting policies can provide an intermediate layer of protection by restricting which USB devices can be connected to systems, thereby limiting the attack surface. Network segmentation and USB port restriction policies can also help contain the potential impact of such attacks, particularly in enterprise environments where multiple users may have access to the same systems. Security monitoring should include detection of unusual USB device connection patterns and system crash events that may indicate exploitation attempts.