CVE-2004-0962 in Remote Desktop
Summary
by MITRE
Apple Remote Desktop Client 1.2.4 executes a GUI application as root when it is started by an Apple Remote Desktop Administrator application, which allows remote authenticated users to execute arbitrary code when loginwindow is active via Fast User Switching.
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Analysis
by VulDB Data Team • 07/21/2017
This vulnerability exists in Apple Remote Desktop Client version 1.2.4 where the application fails to properly validate execution privileges when launched by an administrator. The flaw occurs during the Fast User Switching process when the loginwindow service is active, creating a privilege escalation opportunity. The vulnerability stems from improper access control mechanisms that allow authenticated users to manipulate the execution context of GUI applications with elevated privileges. When the Apple Remote Desktop Administrator application initiates the client, it inadvertently grants root execution rights to the GUI component, bypassing normal security boundaries that should prevent such privilege escalation. This creates a critical security gap where remote authenticated users can leverage their administrative access to execute arbitrary code with root privileges, effectively compromising the entire system. The vulnerability is particularly dangerous because it operates within the legitimate administrative framework of Apple Remote Desktop, making it difficult to detect and distinguish from normal administrative operations. This issue directly relates to CWE-276, which addresses improper privileges, and aligns with ATT&CK technique T1068, which covers local privilege escalation through system administration tools. The vulnerability demonstrates a fundamental flaw in how the application handles privilege delegation during user switching operations, where the system fails to properly isolate execution contexts between different user sessions.
The technical implementation of this vulnerability relies on the interaction between the Apple Remote Desktop Administrator application and the loginwindow service. When Fast User Switching is active, the system maintains multiple user sessions in a way that creates opportunities for privilege manipulation. The client application, when initiated by an administrator, inherits elevated privileges that should be restricted to specific administrative functions. The flaw occurs because the application does not properly sanitize or validate the execution environment before launching GUI components with root access. This creates a condition where remote authenticated users can exploit the legitimate administrative interface to gain unauthorized root access. The vulnerability is particularly insidious because it requires minimal privileges to exploit, only needing authentication to the Apple Remote Desktop system. The execution context is manipulated through the Fast User Switching mechanism, which is designed for legitimate user convenience but becomes a security vector due to improper privilege handling. The system's trust model is compromised when it allows GUI applications to execute with root privileges during user switching operations without proper access control validation.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise. Remote authenticated users can leverage this vulnerability to execute arbitrary commands with root privileges, potentially leading to data theft, system modification, or complete system takeover. The vulnerability affects systems where Apple Remote Desktop is deployed and where Fast User Switching is enabled, creating widespread exposure across enterprise environments. Attackers can use this privilege escalation to install persistent backdoors, modify system files, or exfiltrate sensitive data without detection. The vulnerability is particularly concerning in environments where Apple Remote Desktop is used for remote administration, as it provides attackers with a legitimate path to gain root access. The impact is amplified by the fact that the exploitation requires minimal effort beyond authentication, making it attractive to threat actors. Systems with multiple user sessions active through Fast User Switching present the highest risk, as the vulnerability can be exploited from any remote location with administrative credentials. Organizations using Apple Remote Desktop for remote administration face significant risk if they do not patch this vulnerability, as it essentially provides a backdoor for attackers to gain complete system control.
Mitigation strategies should focus on immediate patching of the Apple Remote Desktop Client to version 1.2.5 or later, which addresses the privilege escalation flaw. Organizations should disable Fast User Switching on systems where Apple Remote Desktop is deployed, as this removes the attack vector entirely. Network segmentation and access control measures should be implemented to limit remote access to administrative functions, reducing the attack surface. Regular security audits should verify that administrative applications are not running with unnecessary privileges, and that proper access controls are in place. System monitoring should be enhanced to detect unusual privilege escalation events or unauthorized execution of GUI applications with root privileges. The recommended approach includes implementing principle of least privilege for administrative tools, ensuring that applications only execute with the minimum required privileges. Security teams should also consider disabling Apple Remote Desktop if it is not essential for operations, as this eliminates the vulnerability entirely. Additional mitigations include implementing strong authentication controls, regular credential rotation, and monitoring for suspicious administrative activities. Organizations should also ensure that their incident response procedures include detection and remediation of privilege escalation vulnerabilities in remote administration tools. The patching process should be prioritized at the highest level due to the critical nature of the vulnerability and its potential for system compromise.