CVE-2019-6176 in USB-C Dock
Summary
by MITRE
A potential vulnerability reported in ThinkPad USB-C Dock Firmware version 3.7.2 may allow a denial of service.
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Analysis
by VulDB Data Team • 02/23/2024
The vulnerability identified as CVE-2019-6176 affects ThinkPad USB-C Dock firmware version 3.7.2 and represents a denial of service weakness that could potentially disrupt system operations. This issue manifests within the firmware layer of Lenovo's docking station hardware, specifically impacting the USB-C dock's ability to maintain stable connections and proper device enumeration. The vulnerability stems from inadequate input validation and error handling mechanisms within the firmware's communication protocols, particularly when processing external device connections and power management signals. Security researchers have identified that this flaw could be exploited by malicious actors to force the dock into an unstable state where connected devices become unresponsive or fail to function properly. The impact extends beyond simple inconvenience as the denial of service could prevent users from accessing critical peripherals such as displays, keyboards, mice, and network adapters that rely on the dock for connectivity.
The technical implementation of this vulnerability involves a specific flaw in the firmware's handling of USB protocol transactions and power delivery negotiations. When a device attempts to establish a connection through the dock's USB-C ports, the firmware fails to properly validate incoming data packets or handle exceptional conditions during the connection establishment process. This weakness creates a potential for a malformed packet or unexpected device behavior to trigger an unhandled exception within the firmware, resulting in a system crash or reboot of the dock's internal components. The vulnerability is particularly concerning because it operates at the firmware level, making it difficult to patch through standard software updates and requiring physical intervention or specialized firmware flashing procedures. According to CWE classification, this vulnerability aligns with CWE-248, which addresses "Uncaught Exception" in software systems, and potentially CWE-399, covering "Resource Management Errors" that can lead to system instability. The flaw represents a classic case of insufficient error handling in embedded systems where the lack of robust exception management leads to complete system failure rather than graceful degradation of service.
From an operational perspective, this vulnerability presents significant risks to enterprise environments where ThinkPad docking stations are extensively deployed. Organizations relying on these docks for business-critical operations could experience unexpected downtime during important meetings, presentations, or collaborative work sessions. The denial of service condition affects not only the dock itself but also all connected devices that depend on the dock for proper functionality, potentially causing cascading failures across multiple systems. Attackers could exploit this vulnerability by connecting specially crafted malicious devices or by manipulating existing connections to trigger the firmware crash. The impact is particularly severe in virtualized environments where desktop virtualization platforms depend on reliable peripheral connectivity for seamless user experiences. According to ATT&CK framework, this vulnerability could be categorized under T1499.004, "Endpoint Denial of Service," where adversaries leverage hardware-level weaknesses to disrupt system availability. The operational consequences include increased help desk tickets, productivity losses, and potential security incidents where the denial of service might mask more sophisticated attacks. Organizations may also face compliance challenges if the vulnerability leads to service disruptions in regulated environments where system availability is mandated by industry standards.
Mitigation strategies for CVE-2019-6176 should focus on both immediate response measures and long-term firmware management protocols. Organizations should implement firmware update procedures to ensure all affected docks are upgraded to versions that address the denial of service vulnerability, typically requiring firmware version 3.7.3 or later. System administrators should establish monitoring protocols to detect unusual connection patterns or device failures that might indicate exploitation attempts. Network segmentation and device access controls can help limit the potential impact by preventing unauthorized devices from connecting to critical docking stations. Regular firmware inventory management should be implemented to track all docking station deployments and ensure timely patching. Additionally, organizations should consider implementing hardware-level security controls such as USB port restrictions or device whitelisting to prevent unauthorized peripheral connections. The vulnerability underscores the importance of maintaining up-to-date firmware across all embedded systems and highlights the need for comprehensive security testing of firmware components. Security teams should also consider conducting vulnerability assessments of other similar hardware components within their infrastructure to identify potential similar weaknesses. Physical security measures including secure storage of firmware update tools and restricted access to docking station maintenance procedures can further reduce exploitation risks. The incident serves as a reminder that embedded systems security requires continuous attention and that vulnerabilities in firmware layers can have significant operational impacts across enterprise environments.