CVE-2018-0378 in NX-OS
Summary
by MITRE
A vulnerability in the Precision Time Protocol (PTP) feature of Cisco Nexus 5500, 5600, and 6000 Series Switches running Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a lack of protection against PTP frame flood attacks. An attacker could exploit this vulnerability by sending large streams of malicious IPv4 or IPv6 PTP traffic to the affected device. A successful exploit could allow the attacker to cause a DoS condition, impacting the traffic passing through the device.
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Analysis
by VulDB Data Team • 05/30/2023
The vulnerability identified as CVE-2018-0378 represents a critical security flaw in Cisco Nexus series switches that impacts the Precision Time Protocol implementation within the NX-OS software ecosystem. This vulnerability specifically affects the Nexus 5500, 5600, and 6000 Series switches, which are widely deployed in enterprise and data center environments for their robust switching capabilities and time synchronization features. The Precision Time Protocol serves as a critical component for maintaining accurate time synchronization across network infrastructure, particularly in environments requiring precise timing for applications such as financial trading systems, telecommunications networks, and industrial control systems. The flaw manifests in the insufficient protection mechanisms against PTP frame flood attacks, creating a significant attack surface that adversaries can exploit to disrupt normal network operations.
The technical root cause of this vulnerability stems from inadequate input validation and protection mechanisms within the PTP processing subsystem of the affected Cisco switches. When the device receives PTP frames, particularly those containing maliciously crafted IPv4 or IPv6 traffic streams, the system fails to implement proper rate limiting or flood protection measures. This absence of defensive controls allows an attacker to overwhelm the switch's processing capabilities by flooding it with excessive PTP traffic, effectively consuming available system resources and processing capacity. The vulnerability operates at the network protocol level, specifically targeting the PTP implementation rather than higher-level application functions, making it particularly insidious as it can bypass traditional network security controls and operate at the layer where time synchronization protocols are processed.
The operational impact of this vulnerability extends beyond simple service disruption, as it can severely compromise the reliability and availability of critical network infrastructure. A successful exploitation of CVE-2018-0378 can result in complete denial of service conditions that affect all network traffic passing through the compromised switch, potentially causing cascading failures throughout the connected network infrastructure. Network administrators may experience complete loss of connectivity to affected devices, with the switch becoming unresponsive and requiring manual intervention for recovery. The vulnerability's remote exploitability means that attackers do not require physical access or network credentials to cause disruption, making it particularly dangerous in environments where network security is paramount. The DoS condition can persist until the device is manually rebooted or until the malicious traffic stream is stopped, potentially causing extended downtime that impacts business operations and service availability.
Mitigation strategies for CVE-2018-0378 should focus on implementing network-level protections and firmware updates to address the underlying vulnerability. Cisco has released software patches and updates specifically designed to resolve this issue, which should be deployed immediately on affected devices. Network administrators should consider implementing access control lists or firewall rules to restrict PTP traffic to only trusted sources, effectively limiting the attack surface. Additionally, monitoring systems should be enhanced to detect unusual PTP traffic patterns that may indicate an ongoing attack, enabling proactive response measures. The implementation of rate limiting controls on PTP traffic at the switch level can provide additional protection against flood attacks. Organizations should also consider disabling PTP functionality entirely if it is not required for their specific network operations, as this eliminates the attack vector altogether. This vulnerability aligns with CWE-400, which categorizes the weakness as "Uncontrolled Resource Consumption" and represents a classic example of how insufficient resource protection mechanisms can lead to denial of service conditions in network infrastructure devices. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique for network denial of service attacks, specifically targeting the network infrastructure components to disrupt service availability.