CVE-2007-3463 in Windows
Summary
by MITRE
** DISPUTED ** Microsoft Windows XP SP2 allows local users, who have sessions created by another user s RunAs (run as) command, to kill arbitrary processes of this other user, as demonstrated by the taskkill program. NOTE: the researcher claims a vendor dispute in which the vendor states that "RunAs and UAC are convenience features, not security boundaries. If you need a security guarantee, please log out and log back in with a different account."
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Analysis
by VulDB Data Team • 08/08/2024
The vulnerability identified as CVE-2007-3463 represents a significant security flaw in Microsoft Windows XP Service Pack 2 that exploits the trust relationships between user sessions created through the RunAs command. This issue demonstrates how convenience features designed for administrative tasks can inadvertently create security boundaries that are easily circumvented by local attackers. The vulnerability specifically affects systems where users have established sessions using the RunAs functionality, which allows them to execute programs with different user credentials than those currently logged in. When such sessions exist, a local attacker can leverage the existing session context to terminate processes belonging to other users, effectively bypassing normal process isolation mechanisms that should protect user sessions from unauthorized interference.
The technical exploitation of this vulnerability relies on the fundamental design flaw in how Windows XP handles process termination requests when multiple user sessions exist through RunAs commands. The taskkill utility, which is designed to terminate processes, can be manipulated by local users to target processes owned by different user accounts within the same system. This occurs because the system does not properly enforce security boundaries between sessions created through RunAs, allowing process termination commands to traverse these artificial boundaries. The vulnerability specifically manifests when a user with a RunAs session attempts to kill processes, as the system fails to validate whether the target process belongs to the current user or another user with whom the session was established. This represents a classic case of inadequate access control enforcement where the system assumes that users operating within a RunAs session have appropriate privileges to manage processes belonging to other users.
The operational impact of this vulnerability extends beyond simple process termination and represents a broader compromise of user session isolation principles that form the foundation of operating system security. Local attackers can leverage this vulnerability to disrupt other users' work, potentially causing denial of service conditions or forcing the termination of critical system processes. The implications are particularly concerning in multi-user environments where users might be running applications with elevated privileges or performing sensitive tasks. From a cybersecurity perspective, this vulnerability demonstrates how administrative convenience features can create attack vectors that adversaries can exploit to escalate their privileges or disrupt system operations. The vulnerability also highlights the importance of proper session management and access control enforcement in operating system design, particularly when implementing features that allow users to temporarily assume different security contexts. This issue directly relates to CWE-284, which addresses improper access control, and aligns with ATT&CK technique T1489, which covers powering off systems through process termination, though in this case the attack is performed through local access rather than network-based disruption.
Microsoft's response to this vulnerability, as indicated in the disputed status, reflects the company's stance that RunAs and User Account Control (UAC) features should not be considered security boundaries. The vendor's position that users who require security guarantees should log out and back in with different accounts represents a fundamental design philosophy that emphasizes the importance of proper session isolation over convenience features. However, this response also acknowledges that the existing implementation creates a security gap that could be exploited by local attackers. The vulnerability underscores the need for operating system vendors to carefully evaluate how administrative convenience features interact with security mechanisms and highlights the importance of clear documentation regarding the security boundaries of such features. Organizations using Windows XP systems should consider implementing additional security controls such as mandatory access controls, process isolation measures, and regular security audits to mitigate the risks associated with this vulnerability. The incident also demonstrates the importance of understanding the difference between convenience features and security boundaries, as the RunAs functionality, while useful for administrators, should not be treated as a security mechanism that can be relied upon to protect against unauthorized access or process manipulation.