CVE-2017-16646 in Linux
Summary
by MITRE
drivers/media/usb/dvb-usb/dib0700_devices.c in the Linux kernel through 4.13.11 allows local users to cause a denial of service (BUG and system crash) or possibly have unspecified other impact via a crafted USB device.
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Analysis
by VulDB Data Team • 01/06/2023
The vulnerability identified as CVE-2017-16646 resides within the Linux kernel's digital video broadcasting over usb subsystem, specifically in the dib0700_devices.c file. This flaw affects kernel versions through 4.13.11 and represents a critical security issue that can be exploited by local attackers through maliciously crafted USB devices. The vulnerability stems from inadequate input validation and error handling within the kernel's usb dvb driver implementation, creating a path for privilege escalation and system instability.
The technical flaw manifests when the kernel processes usb device descriptors from dvb-usb devices without proper bounds checking or validation of device configuration data. This allows an attacker with physical access to a system to connect a malicious usb device that triggers a kernel BUG condition, resulting in immediate system crash or denial of service. The vulnerability is particularly concerning because it operates at the kernel level where malicious input can bypass user-space protections and directly impact system stability. The flaw falls under CWE-129 Input Validation and CWE-248 Unchecked Return Value, as the kernel fails to validate device data and does not properly handle error conditions during usb device initialization.
Operationally, this vulnerability presents a significant risk to systems running affected kernel versions, particularly those in environments where physical access control is insufficient or where users might connect untrusted usb devices. The impact extends beyond simple denial of service, as the kernel BUG condition can potentially lead to more severe consequences including system instability, data corruption, or even privilege escalation depending on the specific attack vector and system configuration. The local nature of the exploit means that physical access to the target system is required, but this access requirement does not necessarily prevent exploitation in environments where untrusted users have physical access to computing resources.
Mitigation strategies for CVE-2017-16646 should prioritize immediate kernel updates to versions that contain the patched dib0700 driver implementation. Organizations should implement strict usb device access controls and disable unnecessary usb functionality where possible. System administrators should consider disabling usb support for dvb devices in environments where such devices are not required, following the principle of least privilege as outlined in cybersecurity frameworks. Additionally, monitoring for unusual system crashes or kernel BUG messages can help detect exploitation attempts. The vulnerability aligns with ATT&CK technique T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation, as it provides a pathway for local users to exploit kernel-level weaknesses and potentially gain elevated privileges. Regular security audits and kernel version management should be implemented to prevent similar vulnerabilities from affecting systems in the future, with particular attention to usb device handling code that interfaces with kernel subsystems.