CVE-2004-2176 in Windows
Summary
by MITRE
the internet connection firewall (icf) in microsoft windows xp sp2 is configured by default to trust sessmgr.exe which allows local users to use sessmgr.exe to create a local listening port that bypasses the icf access controls.
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Analysis
by VulDB Data Team • 08/19/2025
The vulnerability described in CVE-2004-2176 represents a significant security flaw in the Internet Connection Firewall implementation within Microsoft Windows XP Service Pack 2. This issue stems from the improper configuration of firewall trust relationships that allows local users to exploit a legitimate system component to circumvent network access controls. The Internet Connection Firewall serves as a critical network protection mechanism that should prevent unauthorized external access to a system while controlling internal network traffic. However, the default configuration includes an exception for sessmgr.exe, a legitimate Windows service responsible for session management and remote desktop functionality.
The technical flaw manifests through the trust relationship established between the ICF and sessmgr.exe, which creates an unintended attack vector for local users. When sessmgr.exe is executed with appropriate privileges, it can establish local listening ports that are not subject to the normal firewall filtering rules. This bypass mechanism effectively allows malicious users to create network listening endpoints that remain invisible to the firewall's access control policies. The vulnerability is particularly concerning because it operates at the local privilege level, meaning any user with access to the system can potentially exploit this weakness without requiring elevated administrative credentials. The flaw directly relates to CWE-284, which addresses improper access control mechanisms, and specifically demonstrates how trust relationships can be manipulated to undermine security controls.
From an operational impact perspective, this vulnerability enables local users to establish persistent network listening endpoints that can be used for various malicious activities including port forwarding, remote access tunneling, and covert communication channels. Attackers can leverage this capability to create backdoors that remain undetected by standard firewall monitoring systems, as the listening ports are not subject to the same access restrictions that would normally apply to external connections. The vulnerability also undermines the principle of least privilege by allowing local users to bypass network security controls that are designed to protect against external threats. This creates a scenario where internal network compromise can lead to external network exposure without proper authorization controls.
Mitigation strategies for this vulnerability should focus on modifying the default firewall configuration to remove the trust relationship between ICF and sessmgr.exe. System administrators should implement strict access controls for sessmgr.exe execution and monitor for unauthorized usage of this component. The recommended approach includes disabling unnecessary services that could be exploited, implementing additional network monitoring to detect unusual listening port activity, and ensuring that only authorized users have the capability to execute sessmgr.exe with elevated privileges. Organizations should also consider implementing network segmentation and additional host-based security controls to limit the potential impact of local privilege escalation. This vulnerability highlights the importance of regularly reviewing default security configurations and demonstrates how seemingly legitimate system components can be exploited to undermine network security controls, aligning with ATT&CK technique T1068 which covers local privilege escalation through trusted process manipulation.