CVE-2019-10207 in Linux
Summary
by MITRE
A flaw was found in the Linux kernel's Bluetooth implementation of UART, all versions kernel 3.x.x before 4.18.0 and kernel 5.x.x. An attacker with local access and write permissions to the Bluetooth hardware could use this flaw to issue a specially crafted ioctl function call and cause the system to crash.
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Analysis
by VulDB Data Team • 02/27/2024
This vulnerability exists within the Linux kernel's Bluetooth subsystem specifically affecting UART (Universal Asynchronous Receiver-Transmitter) implementations. The flaw manifests in kernel versions 3.x.x prior to 4.18.0 and 5.x.x versions, representing a significant security gap that could be exploited by malicious actors with local access to a system. The vulnerability stems from insufficient input validation within the ioctl (input/output control) function calls that are used to communicate with Bluetooth hardware drivers. When an attacker with local privileges and write permissions to Bluetooth hardware components issues a specially crafted ioctl command, the kernel fails to properly validate the input parameters, leading to a kernel panic or system crash. This represents a classic buffer overflow or improper input handling vulnerability that can result in denial of service conditions.
The technical implementation of this vulnerability involves the kernel's Bluetooth UART driver failing to properly validate ioctl command parameters before processing them. When a malicious ioctl call is made with crafted data, the kernel's Bluetooth subsystem does not adequately check the validity of the input, allowing malformed data to be processed in kernel space. This creates a path for privilege escalation and system instability, as the kernel's response to invalid input causes a crash rather than gracefully handling the error. The vulnerability is classified as a local privilege escalation vector since it requires local access and write permissions to the Bluetooth hardware, making it less accessible than remote exploits but still concerning for systems where local users might have elevated privileges.
The operational impact of this vulnerability extends beyond simple system crashes, as it can be leveraged to create persistent denial of service conditions that could affect critical infrastructure or embedded systems relying on Bluetooth connectivity. In enterprise environments, this vulnerability could be exploited by malicious insiders or compromised local accounts to disrupt services, particularly in scenarios where Bluetooth is used for device management or wireless communication protocols. The vulnerability affects a wide range of kernel versions, making it particularly concerning for organizations maintaining older kernel versions or those unable to immediately patch their systems. From an attack perspective, this aligns with the ATT&CK framework's privilege escalation techniques where local attackers can leverage kernel-level vulnerabilities to gain more control over systems.
Security researchers have identified this vulnerability as a critical issue within the Linux kernel's Bluetooth subsystem, with the CWE (Common Weakness Enumeration) classification pointing to improper input validation and potentially related to CWE-121 for buffer overflow conditions in kernel space. The vulnerability's exploitation requires a local attacker with write access to Bluetooth hardware, which may limit its exposure in some environments but still poses significant risk to systems where local users have elevated privileges or where Bluetooth interfaces are accessible to untrusted users. Organizations should prioritize patching their kernel versions to 4.18.0 or later, or applying the appropriate security patches to prevent exploitation of this vulnerability. The fix typically involves implementing proper input validation and bounds checking in the Bluetooth UART driver's ioctl handling code, ensuring that all input parameters are properly validated before kernel processing occurs.
This vulnerability demonstrates the importance of kernel security testing and the potential risks associated with hardware interface drivers in operating systems. The fact that it affects multiple kernel version streams indicates a fundamental flaw in the Bluetooth implementation that required a comprehensive fix across kernel releases. System administrators should monitor for this vulnerability in their environments and ensure that all kernel updates are applied promptly, particularly in systems where Bluetooth functionality is actively used or where local privilege escalation risks are a concern. The vulnerability serves as a reminder of the critical nature of kernel-level security and the need for robust input validation in all system components that interface with hardware drivers.