CVE-2018-0094 in UCS Central Software
Summary
by MITRE
A vulnerability in IPv6 ingress packet processing for Cisco UCS Central Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition due to high CPU utilization on the targeted device. The vulnerability is due to insufficient rate limiting protection for IPv6 ingress traffic. An attacker could exploit this vulnerability by sending the affected device a high rate of IPv6 packets. Successful exploitation could allow the attacker to cause a DoS condition due to CPU and resource constraints. Cisco Bug IDs: CSCuv34544.
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Analysis
by VulDB Data Team • 02/01/2021
This vulnerability affects Cisco UCS Central Software version 2.0 through 2.1 and represents a significant denial of service weakness in IPv6 packet handling. The flaw stems from inadequate rate limiting mechanisms that fail to properly control the volume of incoming IPv6 traffic, creating an exploitable condition where an unauthenticated remote attacker can overwhelm the system through excessive packet flooding. The vulnerability specifically targets the ingress packet processing functionality of the software, which handles incoming network traffic destined for the UCS Central device. According to Cisco bug ID CSCuv34544, this issue manifests as sustained high CPU utilization that can ultimately lead to complete system unresponsiveness and service disruption.
The technical exploitation of this vulnerability occurs through the systematic transmission of high-volume IPv6 packets to the affected device, bypassing any authentication requirements due to the lack of proper access controls on the ingress processing path. The insufficient rate limiting protection means that the system cannot effectively distinguish between legitimate traffic and malicious packet floods, causing the CPU resources to become consumed entirely by processing these packets. This creates a resource exhaustion scenario where normal operations cannot proceed due to the overwhelming computational demands placed on the system. The vulnerability aligns with CWE-770, which describes inadequate resource management where insufficient controls lead to resource exhaustion attacks that can cause system instability or complete service disruption.
The operational impact of this vulnerability extends beyond simple service interruption, as it can severely compromise the availability of critical infrastructure management functions within the UCS Central environment. Organizations relying on this software for data center management and orchestration could face complete operational paralysis when under attack, potentially affecting multiple server racks and network segments managed through the centralized platform. The remote nature of the exploit means that attackers can target vulnerable systems from anywhere on the network without requiring physical access or valid credentials, making this vulnerability particularly dangerous in environments where network segmentation is not properly implemented. This weakness directly violates the principle of least privilege and resource isolation that should be maintained in enterprise network infrastructure.
Mitigation strategies should focus on implementing robust rate limiting controls at multiple network layers, including perimeter firewalls, network access control devices, and direct system-level configurations within the Cisco UCS Central software. Network administrators should consider deploying IPv6 traffic filtering policies that can identify and limit suspicious packet patterns, while also implementing monitoring solutions that can detect unusual CPU utilization spikes that may indicate exploitation attempts. The implementation of ingress traffic shaping and bandwidth limiting mechanisms can provide additional protection against this specific attack vector. Organizations should also maintain current software versions and apply Cisco's security patches as soon as they become available, since this vulnerability has been addressed through software updates that enhance rate limiting and packet processing controls. The ATT&CK framework categorizes this type of vulnerability under privilege escalation and resource exhaustion techniques, emphasizing the need for comprehensive network defense strategies that include both preventive measures and active threat detection capabilities.