CVE-2007-5079 in Linux
Summary
by MITRE
Red Hat Enterprise Linux 4 does not properly compile and link gdm with tcp_wrappers on x86_64 platforms, which might allow remote attackers to bypass intended access restrictions.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 06/04/2025
The vulnerability identified as CVE-2007-5079 represents a critical security flaw in Red Hat Enterprise Linux 4 systems running on x86_64 architecture where the graphical display manager gdm fails to properly integrate with tcp_wrappers functionality. This issue stems from improper compilation and linking processes that prevent the system from effectively enforcing access control policies established through tcp_wrappers. The tcp_wrappers mechanism serves as a fundamental network access control framework that traditionally provides a first line of defense by allowing or denying access based on host-based access control lists. When gdm is not correctly compiled with tcp_wrappers support, it creates a security gap where remote attackers can potentially circumvent the intended access restrictions that should govern connections to the graphical login service. This flaw directly impacts the principle of least privilege and undermines the layered security approach that organizations rely upon to protect their systems.
The technical root cause of this vulnerability lies in the build process of gdm on x86_64 platforms within the Red Hat Enterprise Linux 4 environment. During compilation, the gdm package fails to properly link against the tcp_wrappers library or correctly implement the necessary socket-level access control checks that would normally be enforced by tcp_wrappers. This misconfiguration results in gdm operating without the expected network access control mechanisms that would normally be provided by the tcp_wrappers framework. The vulnerability specifically affects x86_64 architecture because the compilation flags and linking procedures differ between this platform and others, creating an architecture-specific build issue. According to CWE-254, this represents a weakness in the security configuration of the system, specifically related to improper access control implementation. The flaw essentially creates a scenario where gdm accepts connections without properly consulting the tcp_wrappers access control lists, potentially allowing unauthorized remote access to the graphical login interface.
The operational impact of this vulnerability extends beyond simple access control bypass and represents a significant risk to system security and integrity. Remote attackers who can exploit this vulnerability may gain unauthorized access to the graphical login interface, potentially leading to full system compromise through credential theft, privilege escalation, or other malicious activities. The vulnerability affects the confidentiality, integrity, and availability of the system by removing a critical access control mechanism that should prevent unauthorized network connections to the display manager service. This creates an attack surface that could be leveraged for reconnaissance, lateral movement within the network, or as a stepping stone for more sophisticated attacks. The vulnerability particularly impacts enterprise environments where graphical login services are used for administrative access, as it undermines the trust model that organizations rely upon for securing their systems. From an ATT&CK framework perspective, this vulnerability maps to T1078 Valid Accounts and T1566 Phishing, as it could enable attackers to gain access through compromised credentials or by exploiting the bypassed access controls to establish persistence.
Mitigation strategies for CVE-2007-5079 should focus on immediate system hardening and long-term architectural improvements to prevent similar issues. The primary remediation involves rebuilding gdm with proper tcp_wrappers support on x86_64 platforms or applying the appropriate security patches provided by Red Hat. Organizations should also implement additional network-level controls such as firewall rules that restrict direct access to the gdm service ports, typically port 177 or 6000, to provide defense in depth. System administrators should verify that tcp_wrappers is properly configured and that access control lists are correctly defined for the gdm service. The vulnerability highlights the importance of proper build and compilation processes in maintaining security posture, and organizations should implement continuous monitoring to ensure that security features are properly integrated during software compilation. Additionally, regular security audits of system components and their compilation settings should be conducted to prevent similar configuration issues from arising in other system services that rely on access control mechanisms.