CVE-2016-2188 in Linux
Summary
by MITRE
The iowarrior_probe function in drivers/usb/misc/iowarrior.c in the Linux kernel before 4.5.1 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.
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Analysis
by VulDB Data Team • 10/13/2024
The vulnerability identified as CVE-2016-2188 resides within the Linux kernel's USB subsystem, specifically in the iowarrior_probe function located in drivers/usb/misc/iowarrior.c. This flaw represents a critical denial of service vulnerability that can be exploited by attackers who are physically proximate to the target system. The vulnerability affects Linux kernel versions prior to 4.5.1, making it a significant concern for systems that may be exposed to local physical access threats. The issue manifests when a malicious USB device presents a crafted endpoints value in its device descriptor, which the kernel's USB driver processing fails to properly validate or handle.
The technical root cause of this vulnerability stems from inadequate input validation within the USB device descriptor processing logic. When the iowarrior_probe function encounters a USB device with malformed endpoint information, it attempts to dereference a NULL pointer without proper null checks or error handling mechanisms. This programming flaw falls under the CWE-476 category of NULL Pointer Dereference, which is a well-documented vulnerability pattern that occurs when software attempts to access memory through a pointer that has not been properly initialized or validated. The function fails to validate the endpoint descriptor structure before attempting to process it, creating an exploitable condition that can lead to immediate system crash and complete denial of service.
The operational impact of this vulnerability extends beyond simple system disruption, as it provides attackers with a reliable method to crash systems without requiring network connectivity or complex exploitation techniques. The physical proximity requirement means that attackers can leverage this vulnerability in scenarios such as public computing environments, shared workspaces, or any location where USB devices can be physically connected to target systems. This makes the vulnerability particularly concerning for enterprise environments, government facilities, or any organization that cannot guarantee physical security of their computing infrastructure. The system crash resulting from this vulnerability can lead to complete service interruption, potential data loss, and may require system reboot to restore normal operation, potentially causing business disruption and security incidents.
Mitigation strategies for CVE-2188 should prioritize immediate kernel version updates to 4.5.1 or later, where the vulnerability has been patched through proper input validation and null pointer checks in the USB device descriptor processing. System administrators should also implement USB device whitelisting policies to restrict which USB devices can connect to critical systems, particularly in environments where physical security cannot be guaranteed. Additionally, organizations should consider implementing USB port disablement for non-essential systems or deploying USB device monitoring solutions that can detect and alert on suspicious USB device connections. From a defensive perspective, this vulnerability aligns with ATT&CK technique T1059.001 for system compromise through local execution, and represents a classic example of how physical access can be leveraged to achieve system-level compromise, emphasizing the importance of layered security approaches that address both network-based and physical access threats.