CVE-2011-0963 in Nac Guest Server
Summary
by MITRE
The default configuration of the RADIUS authentication feature on the Cisco Network Access Control (NAC) Guest Server with software before 2.0.3 allows remote attackers to bypass intended access restrictions and obtain network connectivity via unspecified vectors, aka Bug ID CSCtj66922.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 11/03/2024
The vulnerability identified as CVE-2011-0963 affects the Cisco Network Access Control NAC Guest Server implementation where the default configuration of the RADIUS authentication feature contains a security flaw that permits unauthorized network access. This issue specifically impacts systems running software versions prior to 2.0.3, creating a significant security gap in network access control mechanisms. The vulnerability enables remote attackers to circumvent the intended access restrictions that should govern guest network connectivity, effectively allowing unauthorized users to gain network access through unspecified attack vectors. This represents a critical weakness in the authentication framework that undermines the fundamental security posture of the network access control system.
The technical flaw manifests in the default configuration of the RADIUS authentication process within the Cisco NAC Guest Server, where the system fails to properly enforce access controls during the authentication phase. This misconfiguration allows attackers to exploit the authentication mechanism without proper credentials or authorization, bypassing the intended security boundaries that should restrict guest network access. The unspecified vectors suggest that the vulnerability may be exploitable through multiple attack paths including but not limited to authentication bypass techniques, session manipulation, or credential spoofing approaches. The vulnerability operates at the authentication layer, specifically targeting the RADIUS protocol implementation that governs how guest users are authenticated and authorized for network access within the Cisco NAC environment.
The operational impact of this vulnerability is substantial as it allows remote attackers to gain unauthorized network connectivity without proper authentication, potentially leading to complete network compromise. Attackers could leverage this vulnerability to establish persistent access to the network, conduct reconnaissance activities, or launch further attacks against internal systems. The vulnerability affects the core security functionality of the NAC Guest Server, which is designed to provide controlled access to guest users while maintaining network security boundaries. This compromise undermines the trust model of the network access control system and could result in unauthorized data access, network infiltration, and potential lateral movement within the network infrastructure. The impact extends beyond simple unauthorized access as it represents a fundamental failure in the network's access control mechanisms.
Organizations should immediately upgrade their Cisco NAC Guest Server software to version 2.0.3 or later to remediate this vulnerability, as this represents the primary and most effective mitigation strategy. Network administrators should also implement additional monitoring and logging controls to detect potential exploitation attempts, particularly focusing on authentication events and unusual access patterns. The vulnerability aligns with CWE-284 which addresses improper access control in software systems, specifically targeting the authentication and authorization mechanisms that should protect network resources. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation and initial access tactics, where attackers can bypass authentication controls to gain network access. Additional mitigations include implementing network segmentation, enforcing strict access controls on the NAC server itself, and conducting regular security assessments to identify similar configuration weaknesses in other network components. The vulnerability demonstrates the critical importance of proper default configurations in network security systems and the potential consequences when authentication mechanisms are improperly implemented or configured.