CVE-2013-2896 in Linux
Summary
by MITRE
drivers/hid/hid-ntrig.c in the Human Interface Device (HID) subsystem in the Linux kernel through 3.11, when CONFIG_HID_NTRIG is enabled, allows physically proximate attackers to cause a denial of service (NULL pointer dereference and OOPS) via a crafted device.
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Analysis
by VulDB Data Team • 05/21/2021
The vulnerability identified as CVE-2013-2896 resides within the Linux kernel's Human Interface Device subsystem, specifically in the hid-ntrig driver component. This flaw affects kernel versions through 3.11 and manifests when the CONFIG_HID_NTRIG configuration option is enabled, making it particularly relevant for systems that support certain types of digitizer tablets and touchscreen devices. The vulnerability represents a classic null pointer dereference issue that can be exploited by attackers who have physical proximity to the target system, positioning it as a local privilege escalation vector with remote exploitation potential through physical access scenarios.
The technical implementation of this vulnerability occurs within the hid-ntrig.c driver file where improper input validation leads to a situation where a NULL pointer is dereferenced during device handling operations. When a maliciously crafted HID device connects to a system with the vulnerable kernel version and CONFIG_HID_NTRIG enabled, the driver fails to properly validate device descriptors or initialization parameters before attempting to access memory locations. This results in an immediate kernel crash manifested as an OOPS condition, effectively causing a denial of service that renders the affected system unusable until manual reboot or kernel reload occurs. The vulnerability's impact is amplified by the fact that it occurs at the kernel level, bypassing typical user-space protections and security mechanisms.
From an operational perspective, this vulnerability creates significant risk for environments where physical security is compromised or where untrusted devices might be connected to systems. The attack vector requires only physical proximity, making it particularly dangerous in shared workspaces, public computing environments, or any scenario where removable devices can be introduced without proper security controls. Organizations utilizing Linux systems for critical operations face potential operational disruptions, as the denial of service can occur without any network connectivity requirements, making it difficult to detect and prevent through traditional network-based security measures. The vulnerability also represents a potential stepping stone for more sophisticated attacks, as the kernel crash could be leveraged to gain additional system information or to create conditions for further exploitation attempts.
The mitigation strategies for this vulnerability primarily involve kernel version updates to versions beyond 3.11 where the issue has been resolved through proper input validation and null pointer checks within the hid-ntrig driver. System administrators should also consider disabling the CONFIG_HID_NTRIG option if the specific hardware support is not required, effectively preventing the vulnerable driver from loading into the kernel space. Additionally, implementing physical security controls such as device whitelisting, port restriction policies, and proper device management protocols can significantly reduce the attack surface. From a security framework perspective, this vulnerability aligns with CWE-476 which addresses NULL pointer dereference conditions, and it maps to ATT&CK technique T1059.001 for command and scripting interpreter execution through kernel-level exploits. Organizations should also consider implementing kernel lockdown mechanisms and secure boot configurations to prevent unauthorized kernel module loading and reduce the overall attack surface available to potential attackers.