CVE-2013-1213 in NX-OS
Summary
by MITRE
Cisco NX-OS on the Nexus 1000V does not assign the proper priority to heartbeat messages from a Virtual Ethernet Module (VEM) to a Virtual Supervisor Module (VSM), which allows remote attackers to cause a denial of service (false VEM unavailability report) via a flood of UDP packets, aka Bug ID CSCud14840.
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Analysis
by VulDB Data Team • 05/04/2019
The vulnerability identified as CVE-2013-1213 affects Cisco NX-OS software running on Nexus 1000V virtual switches, specifically within the communication protocols between Virtual Ethernet Modules and Virtual Supervisor Modules. This issue represents a critical flaw in the heartbeat message handling mechanism that governs the operational status reporting between these virtual components. The vulnerability stems from improper priority assignment in the processing of heartbeat messages, which are essential for maintaining the health and availability status of virtual network components within the Cisco Nexus 1000V platform.
The technical implementation of this vulnerability involves the failure of the Virtual Supervisor Module to properly prioritize heartbeat messages originating from Virtual Ethernet Modules. Heartbeat messages serve as critical health indicators that confirm the operational status of virtual network components and maintain the integrity of the virtual switching fabric. When the VSM fails to assign appropriate priority to these messages, it creates a condition where legitimate heartbeat communications can be overwhelmed or deprioritized by other network traffic. This misconfiguration allows malicious actors to exploit the system by flooding the network with UDP packets that mimic or interfere with legitimate heartbeat traffic, ultimately causing the VSM to incorrectly report VEM unavailability.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it fundamentally compromises the reliability and stability of virtual network infrastructures. Remote attackers can leverage this weakness to trigger false VEM unavailability reports, which may lead to unnecessary failovers, service disruptions, and potential network partitioning within virtualized environments. The attack vector specifically targets UDP packet flooding, making it particularly effective against systems that do not adequately implement rate limiting or traffic prioritization for critical heartbeat communications. This vulnerability affects organizations relying on Cisco Nexus 1000V deployments for virtualized network services, potentially impacting data center operations and cloud computing environments where high availability is paramount.
Mitigation strategies for CVE-2013-1213 should focus on implementing network traffic controls and priority management mechanisms that ensure heartbeat messages maintain their critical status within the virtual switching environment. Organizations should deploy ingress filtering and rate limiting mechanisms to prevent UDP packet flooding attacks targeting the heartbeat communication channels. Network administrators should also consider implementing Quality of Service policies that prioritize heartbeat traffic over other network communications, ensuring that virtual network components maintain their operational status reporting integrity. Additionally, regular monitoring of VEM-VSM communication patterns can help detect anomalous behavior that may indicate exploitation attempts. The vulnerability aligns with CWE-20 Improper Input Validation and ATT&CK technique T1498 for Denial of Service, emphasizing the need for robust input validation and traffic prioritization controls in virtualized network environments.
This vulnerability demonstrates the complexities inherent in virtualized network security, where traditional network security measures may prove insufficient against attacks targeting protocol-level communication mechanisms. The attack scenario represents a sophisticated approach to network disruption that exploits the fundamental assumptions about communication priority within virtualized infrastructures. Organizations should also consider implementing network segmentation strategies that isolate critical virtual switching components and deploy intrusion detection systems specifically configured to monitor for heartbeat message anomalies. Regular security updates and patches should be applied to maintain the integrity of the NX-OS software, as this vulnerability highlights the importance of proper priority assignment in maintaining virtual network reliability. The incident underscores the critical need for comprehensive security testing of virtualized network components and the implementation of defense-in-depth strategies that protect against both external attacks and internal communication failures within virtualized environments.