CVE-2006-6899 in BlueZ
Summary
by MITRE
hidd in BlueZ (bluez-utils) before 2.25 allows remote attackers to obtain control of the (1) Mouse and (2) Keyboard Human Interface Device (HID) via a certain configuration of two HID (PSM) endpoints, operating as a server, aka HidAttack.
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Analysis
by VulDB Data Team • 06/14/2025
The vulnerability described in CVE-2006-6899 represents a critical security flaw in the BlueZ Bluetooth stack implementation that affected versions prior to 2.25. This issue specifically targets the HID (Human Interface Device) protocol handling within the Bluetooth HID profile, where the hidd daemon processes incoming HID connections. The vulnerability arises from improper handling of multiple HID endpoints, particularly when two HID Profile Service Multiplexer (PSM) endpoints are configured to operate as servers simultaneously, creating a scenario where remote attackers can exploit this configuration to gain unauthorized control over HID devices such as keyboards and mice.
The technical flaw stems from the insufficient validation and management of HID endpoint configurations within the BlueZ stack. When two HID endpoints are configured to operate as servers, the system fails to properly differentiate between legitimate connection requests and malicious attempts to hijack the HID communication channels. This misconfiguration allows an attacker to manipulate the HID protocol negotiation process, effectively enabling them to establish unauthorized control over HID devices that are connected via Bluetooth. The vulnerability specifically impacts the HID protocol implementation where the hidd daemon serves as the central component managing HID device connections and data flow between Bluetooth devices and the host system.
The operational impact of this vulnerability is significant as it enables remote code execution and complete control over connected HID devices without requiring physical access or user interaction. Attackers can leverage this vulnerability to perform various malicious activities including keystroke logging, mouse movement manipulation, and potentially gaining deeper access to the compromised system. The attack vector operates entirely over the network, making it particularly dangerous as it can be exploited from remote locations. This vulnerability essentially transforms legitimate HID communication into a potential attack surface where malicious actors can intercept, modify, or take complete control of HID device communications, effectively allowing them to impersonate legitimate HID devices and execute arbitrary commands through the HID protocol.
The vulnerability aligns with CWE-284 (Improper Access Control) and represents a classic example of inadequate privilege separation in network protocol implementations. From an ATT&CK framework perspective, this vulnerability maps to T1059 (Command and Scripting Interpreter) and T1071 (Application Layer Protocol) as attackers can leverage the HID protocol to execute commands and establish persistent access. The attack chain typically involves reconnaissance to identify vulnerable BlueZ implementations, followed by exploitation of the multiple HID endpoint configuration to establish unauthorized HID device control. Organizations using affected BlueZ versions are particularly vulnerable as this flaw affects the core Bluetooth HID functionality that many systems depend upon for wireless input device connectivity.
Mitigation strategies for this vulnerability require immediate patching of BlueZ implementations to version 2.25 or later where the HID endpoint handling has been properly addressed. System administrators should also implement network segmentation to limit Bluetooth access to trusted environments and disable unnecessary HID services when not required. Additional protective measures include monitoring for unusual HID device connections and implementing proper access controls for Bluetooth services. Organizations should conduct thorough vulnerability assessments to identify all systems running affected BlueZ versions and ensure that all Bluetooth HID functionality is properly secured. The patch addresses the root cause by implementing proper endpoint validation and connection management, preventing the exploitation scenario that allowed attackers to manipulate HID protocol endpoints and gain unauthorized device control.