CVE-2005-3631 in udev
Summary
by MITRE
udev does not properly set permissions on certain files in /dev/input which allows local users to obtain sensitive data that is entered at the console such as user passwords.
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Analysis
by VulDB Data Team • 06/29/2025
The vulnerability described in CVE-2005-3631 represents a critical access control flaw within the udev device management system that was prevalent in Unix-like operating systems during that period. This issue specifically affects how udev handles permission settings for device files located in the /dev/input directory tree, which serves as the primary interface for input devices such as keyboards, mice, and touchscreens. The flaw arises from insufficient validation and enforcement of access controls during device node creation and permission assignment, creating a pathway for unauthorized data access that could compromise system security and user privacy.
The technical implementation of this vulnerability stems from udev's failure to properly establish restrictive permissions on input device files within the /dev/input hierarchy. When udev manages device nodes for input peripherals, it should enforce strict access controls to prevent unauthorized processes from reading sensitive data that flows through these interfaces. However, in affected systems, the permission setting mechanism was inadequate, allowing local users to gain access to input device files that should have been restricted to privileged processes only. This misconfiguration particularly impacted keyboard input handling where console passwords and other sensitive data entered by users could potentially be intercepted by malicious local processes.
The operational impact of this vulnerability extends beyond simple information disclosure, creating significant risks for system integrity and user privacy. Local attackers with basic user privileges could exploit this weakness to monitor and capture keystrokes entered at the console, potentially compromising authentication credentials, confidential communications, and other sensitive information. The attack vector is particularly concerning because it requires no elevated privileges and can be executed by any user with access to the system, making it a persistent threat that could remain undetected for extended periods. This vulnerability directly relates to CWE-276, which addresses improper file permissions, and aligns with ATT&CK technique T1056.001 for input capture through keyboard logging.
Mitigation strategies for CVE-2005-3631 involve immediate system updates and configuration hardening measures to ensure proper access control enforcement. System administrators should prioritize updating udev packages to versions that correctly implement permission settings for device files, particularly those in /dev/input directories. Additional protective measures include implementing stricter file system permissions, monitoring access patterns to input device files, and deploying intrusion detection systems that can identify suspicious activities related to device node access. The vulnerability highlights the importance of proper privilege separation and access control enforcement in device management systems, emphasizing that device node creation and permission assignment must be handled with the same security rigor applied to other critical system components. Organizations should also consider implementing additional security controls such as mandatory access controls and privilege separation mechanisms to prevent similar issues from compromising system security.