CVE-2002-2316 in CatOS
Summary
by MITRE
Cisco Catalyst 4000 series switches running CatOS 5.5.5, 6.3.5, and 7.1.2 do not always learn MAC addresses from a single initial packet, which causes unicast traffic to be broadcast across the switch and allows remote attackers to obtain sensitive network information by sniffing.
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Analysis
by VulDB Data Team • 07/13/2024
The vulnerability identified as CVE-2002-2316 affects Cisco Catalyst 4000 series switches operating with specific CatOS versions including 5.5.5, 6.3.5, and 7.1.2. This flaw represents a significant network security issue that stems from improper MAC address learning mechanisms within the switch's forwarding table management. The vulnerability operates at the data link layer of the OSI model and specifically impacts the switch's ability to properly maintain its MAC address table, which is fundamental to efficient and secure network operations.
The technical flaw manifests when switches fail to properly learn MAC addresses from the initial packet transmission from a device. This failure creates a condition where the switch cannot correctly identify the source MAC address of incoming unicast traffic, resulting in the switch treating legitimate unicast packets as broadcast traffic. The switch essentially broadcasts these packets across all ports instead of forwarding them to the specific destination port, which fundamentally undermines the switch's core function of intelligent traffic forwarding. This behavior creates a security exposure that allows attackers to capture and analyze network traffic that should remain isolated between specific endpoints.
The operational impact of this vulnerability extends beyond simple network performance degradation to create substantial security risks. Remote attackers can exploit this weakness by simply sniffing network traffic on any port connected to the affected switch. The vulnerability enables passive information gathering attacks where sensitive network information can be intercepted without requiring privileged access or complex attack vectors. This exposure allows attackers to potentially discover network topology details, identify active network devices, and gather information about network communications that should remain private. The vulnerability is particularly concerning because it affects the fundamental switching behavior and can be exploited remotely without requiring physical access to the network infrastructure.
From a cybersecurity perspective, this vulnerability aligns with CWE-200, which addresses improper information exposure, and represents a classic example of how network device misconfigurations or implementation flaws can create information disclosure vulnerabilities. The attack pattern follows ATT&CK technique T1046, which involves network service scanning, as attackers can use this vulnerability to map network topology and identify connected devices. The vulnerability also relates to T1562.001, which covers security software discovery, as the improper MAC learning behavior can reveal information about network security implementations. Organizations with affected Cisco switches face increased risk of network reconnaissance and information gathering activities that could lead to more sophisticated attacks targeting other network components.
Mitigation strategies for this vulnerability require immediate attention from network administrators and security teams. The primary recommendation involves upgrading affected Cisco Catalyst 4000 series switches to newer CatOS versions that contain fixes for the MAC learning implementation. Organizations should also implement network segmentation and access controls to limit the potential impact of such vulnerabilities. Network monitoring solutions should be enhanced to detect unusual broadcast traffic patterns that might indicate exploitation attempts. Additionally, implementing proper network access control measures and regular security assessments can help identify and remediate similar vulnerabilities before they can be exploited by malicious actors. The vulnerability demonstrates the critical importance of maintaining up-to-date network infrastructure and the potential consequences of relying on outdated software implementations in network security devices.