CVE-2015-0004 in Windows
Summary
by MITRE
The User Profile Service (aka ProfSvc) in Microsoft Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 allows local users to gain privileges by conducting a junction attack to load another user's UsrClass.dat registry hive, aka MSRC ID 20674 or "Microsoft User Profile Service Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 06/16/2025
The CVE-2015-0004 vulnerability represents a critical privilege escalation flaw within Microsoft's User Profile Service component that affects multiple Windows operating systems including server and client versions. This vulnerability specifically targets the ProfSvc service which manages user profiles and registry hives, creating a pathway for local attackers to escalate their privileges from standard user level to system level access. The flaw stems from improper handling of file system junction points and registry hive loading mechanisms, allowing malicious users to manipulate the system's user profile management processes.
The technical exploitation of this vulnerability relies on a junction attack methodology that leverages the way Windows handles user profile registry hives. When the User Profile Service processes user profile loading operations, it fails to properly validate the integrity of junction points that point to other user's UsrClass.dat files. This allows an attacker to create a symbolic link or junction point that redirects the service to load a malicious registry hive from another user's profile, effectively enabling the attacker to execute code with elevated privileges. The vulnerability is categorized under CWE-264 due to inadequate privilege management and improper access control mechanisms within the service.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete system control capabilities through the loaded registry hive manipulation. Attackers can leverage this vulnerability to modify user profiles, install persistent backdoors, or gain access to sensitive system resources that would normally require administrative privileges. The attack vector is particularly concerning because it requires only local system access and does not necessitate network connectivity or complex exploitation techniques, making it highly accessible to both malicious actors and security researchers. This vulnerability directly maps to the ATT&CK technique T1068 which involves privilege escalation through the exploitation of system-level vulnerabilities.
Mitigation strategies for CVE-2015-0004 should focus on both immediate patching and operational security improvements. Microsoft released security updates that addressed the registry hive loading validation issues and improved the junction point handling within the User Profile Service. Organizations should implement the relevant security patches immediately, particularly for systems running Windows Server 2003, Vista, and Windows 7, which are most affected by this vulnerability. Additionally, system administrators should conduct thorough security audits to identify and remove any existing symbolic links or junction points that could be exploited, while implementing strict access controls on user profile directories. Network segmentation and principle of least privilege enforcement can further reduce the attack surface and limit potential damage from exploitation attempts. The vulnerability demonstrates the critical importance of proper privilege separation and registry hive validation in system services, particularly those handling user profile management operations.