CVE-2005-1942 in Catalyst
Summary
by MITRE
Cisco switches that support 802.1x security allow remote attackers to bypass port security and gain access to the VLAN via spoofed Cisco Discovery Protocol (CDP) messages.
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Analysis
by VulDB Data Team • 06/16/2019
The vulnerability identified as CVE-2005-1942 affects Cisco switches that implement 802.1x security protocols, creating a significant security weakness in network access control mechanisms. This flaw resides in the switch's handling of Cisco Discovery Protocol messages, which are normally used for network device discovery and communication. The vulnerability allows remote attackers to manipulate the network security posture by injecting forged CDP messages that appear legitimate to the switch's security infrastructure.
The technical implementation of this vulnerability stems from insufficient validation of CDP message authenticity within the switch's 802.1x authentication process. When switches receive CDP messages, they typically verify the source device's identity and trust level before making security decisions. However, this specific vulnerability enables attackers to spoof CDP messages with malicious payloads that can trick the switch into believing an unauthorized device is legitimate. The flaw essentially bypasses the intended port security controls that should prevent unauthorized network access based on the 802.1x authentication framework.
From an operational impact perspective, this vulnerability represents a critical risk to network security infrastructure, particularly in environments where 802.1x port security is relied upon for access control. An attacker exploiting this vulnerability can gain unauthorized access to VLANs that should be protected by 802.1x authentication, potentially leading to network infiltration, data exfiltration, and lateral movement within the network. The remote nature of the attack means that threat actors do not need physical access to the network infrastructure, making the vulnerability particularly dangerous in enterprise environments where network segmentation is crucial for security.
The vulnerability maps to CWE-284 Access Control Issues, specifically related to insufficient access control mechanisms within network device protocols. This weakness allows unauthorized access to protected network resources through manipulation of discovery protocols that should be trusted but are not properly validated. From an ATT&CK framework perspective, this vulnerability aligns with techniques such as T1046 Network Service Scanning and T1566 Phishing, as attackers can leverage the compromised switch to establish network access and potentially gain further footholds within the network. The attack chain typically begins with network reconnaissance to identify vulnerable switches, followed by CDP message injection to bypass port security controls.
Mitigation strategies for this vulnerability include implementing strict CDP message validation on network switches, configuring proper access controls on switch management interfaces, and deploying network monitoring solutions that can detect anomalous CDP traffic patterns. Organizations should also consider disabling CDP where it is not required for network operations, implementing network segmentation to limit the scope of potential compromise, and regularly updating switch firmware to address known vulnerabilities. Network administrators should monitor switch logs for unusual CDP message activity and implement intrusion detection systems that can identify and alert on spoofed CDP messages. Additionally, the principle of least privilege should be applied to switch configurations, ensuring that only authorized personnel have access to modify switch security settings and that all network changes are properly documented and reviewed.