CVE-2012-2469 in NX-OS
Summary
by MITRE
Cisco NX-OS 4.2, 5.0, 5.1, and 5.2 on Nexus 7000 series switches, when the High Availability (HA) policy is configured for Reset, allows remote attackers to cause a denial of service (device reset) via a malformed Cisco Discovery Protocol (CDP) packet, aka Bug IDs CSCtk34535 and CSCtk19132.
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Analysis
by VulDB Data Team • 05/04/2019
The vulnerability identified as CVE-2012-2469 represents a critical denial of service flaw affecting Cisco NX-OS software versions 4.2, 5.0, 5.1, and 5.2 running on Nexus 7000 series switches. This vulnerability specifically manifests when the High Availability policy is configured with a Reset action, creating a dangerous condition where remote attackers can exploit malformed Cisco Discovery Protocol packets to trigger device resets. The Cisco Discovery Protocol serves as a network protocol that allows devices to advertise their identity, capabilities, and neighbors to adjacent network devices, making it a fundamental component of network infrastructure communication. The flaw stems from inadequate input validation within the CDP packet processing mechanism, which fails to properly sanitize or validate malformed packets before processing them within the context of HA policy enforcement.
The technical exploitation of this vulnerability occurs through the manipulation of CDP packets that contain malformed data structures or invalid field values. When a Nexus 7000 switch configured with HA Reset policy receives such malformed packets, the system's failure handling mechanism becomes compromised, leading to an unintended device reset operation. This behavior constitutes a direct violation of the principle of least privilege and input validation, as outlined in CWE-20, which addresses weaknesses in input validation. The vulnerability specifically relates to CWE-121, heap-based buffer overflow conditions, and CWE-122, stack-based buffer overflow conditions, as the malformed packet processing likely triggers memory corruption within the CDP handling code. The attack vector is classified as remote, meaning that an attacker does not require physical access or network credentials to exploit this vulnerability, making it particularly dangerous in untrusted network environments.
From an operational impact perspective, this vulnerability poses significant risks to network availability and stability. The ability to remotely reset critical network infrastructure components can lead to service disruptions, network partitioning, and potential cascading failures throughout the network fabric. The Nexus 7000 series switches serve as core components in data center and enterprise network architectures, making this vulnerability particularly concerning for organizations relying on these devices for network connectivity. The HA policy reset functionality, designed to maintain network redundancy and failover capabilities, becomes a point of exploitation rather than protection. This vulnerability directly impacts the availability aspect of the CIA triad and can be categorized under ATT&CK technique T1499.004, which describes network disruption attacks targeting network infrastructure components. The exploitability of this vulnerability means that attackers can repeatedly trigger resets, potentially causing sustained network outages that can last from minutes to hours depending on the network's recovery mechanisms.
Mitigation strategies for CVE-2012-2469 should focus on immediate network protection measures and long-term architectural improvements. Organizations should implement immediate patching of affected NX-OS versions to address the underlying code vulnerabilities in CDP packet processing. Network segmentation and access control measures should be enhanced to limit the exposure of vulnerable switches to untrusted networks, particularly by implementing firewall rules that restrict CDP traffic or disable CDP entirely where possible. The implementation of network monitoring solutions capable of detecting malformed CDP packets can provide early warning capabilities for potential exploitation attempts. Additionally, organizations should consider temporarily disabling HA Reset policies on affected switches until proper patches are applied, though this approach may reduce network redundancy. The vulnerability highlights the importance of secure coding practices and input validation mechanisms, aligning with industry standards such as the OWASP Secure Coding Practices and NIST Special Publication 800-115 for vulnerability management. Network administrators should also implement robust change management procedures to ensure that security updates are deployed promptly and that network configurations are regularly reviewed for potential security weaknesses. The remediation process should include comprehensive testing of patched systems to ensure that the vulnerability is fully resolved without introducing new operational issues.