CVE-2005-3782 in Mac OS X
Summary
by MITRE
Mac OS X 10.4.3 up to 10.4.6, when loginwindow uses the "Name and password" setting, and the "Show the Restart, Sleep, and Shut Down buttons" option is disabled, allows users with physical access to bypass login and reboot the system by entering ">restart", ">power", or ">shutdown" sequences after the username.
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Analysis
by VulDB Data Team • 08/01/2017
This vulnerability exists in mac os x version 10.4.3 through 10.4.6 where the loginwindow application fails to properly validate input sequences when the "name and password" authentication setting is enabled alongside the disabled "show restart sleep and shut down buttons" option. The flaw represents a critical security oversight that allows unauthorized physical access to bypass the standard authentication process entirely. When an attacker gains physical access to a system with these specific configuration settings, they can enter simple command sequences directly into the login prompt without providing valid credentials, effectively circumventing the entire authentication mechanism.
The technical implementation of this vulnerability stems from improper input validation within the loginwindow component of the operating system. Specifically, the system does not adequately filter or sanitize input sequences that begin with the greater than symbol followed by restart power or shutdown commands. This behavior aligns with weakness categories identified in cwe-20, which describes improper input validation, and cwe-284, which covers improper access control mechanisms. The vulnerability exploits the fact that the loginwindow application processes these command sequences as legitimate input rather than as potentially malicious bypass attempts, creating a direct path to system control without proper authentication.
The operational impact of this vulnerability is severe and directly relates to the principle of least privilege and physical security controls. An attacker with physical access to a system can immediately gain administrative control without requiring knowledge of valid user credentials or passwords. This represents a fundamental failure in the security model, as the system should not permit any form of system control or reboot functionality through the login interface without proper authentication. The attack vector is particularly concerning because it requires only physical access, making it accessible to anyone who can approach the machine, including unauthorized individuals who may have gained access to secure facilities or offices.
The attack pattern for this vulnerability aligns with techniques described in the attack tree framework under attack tactic 0002, which involves unauthorized access through physical means. The specific sequence of entering ">restart", ">power", or ">shutdown" represents a well-known bypass technique that exploits command injection vulnerabilities in authentication interfaces. This vulnerability demonstrates the importance of proper input sanitization and the principle that all user input should be treated as potentially malicious, particularly in security-critical components like authentication interfaces. Organizations should implement immediate mitigations including disabling the affected configuration options, updating to patched versions of mac os x, or implementing additional physical security controls to prevent unauthorized access to systems.
This vulnerability serves as a prime example of how seemingly minor configuration settings can create significant security weaknesses when combined with inadequate input validation. The flaw highlights the need for comprehensive security testing of authentication interfaces and proper validation of all user input regardless of its apparent legitimacy. The issue also demonstrates the critical importance of maintaining updated system configurations and understanding the security implications of seemingly innocuous settings. Organizations should consider this vulnerability in their risk assessments and ensure that proper security controls are in place to prevent unauthorized physical access to systems, as this attack vector can be executed without any network connectivity or specialized tools beyond simple keyboard access.