CVE-2018-0303 in NX-OS
Summary
by MITRE
A vulnerability in the Cisco Discovery Protocol component of Cisco FXOS Software and Cisco NX-OS Software could allow an unauthenticated, adjacent attacker to execute arbitrary code as root or cause a denial of service (DoS) condition on the affected device. The vulnerability exists because of insufficiently validated Cisco Discovery Protocol packet headers. An attacker could exploit this vulnerability by sending a crafted Cisco Discovery Protocol packet to a Layer 2 adjacent affected device. A successful exploit could allow the attacker to cause a buffer overflow that could allow the attacker to execute arbitrary code as root or cause a DoS condition on the affected device. This vulnerability affects the following if configured to use Cisco Discovery Protocol: Firepower 4100 Series Next-Generation Firewalls, Firepower 9300 Security Appliance, MDS 9000 Series Multilayer Switches, Nexus 1000V Series Switches, Nexus 1100 Series Cloud Services Platforms, Nexus 2000 Series Fabric Extenders, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode, Nexus 9000 Series Switches in standalone NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, UCS 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCvc22202, CSCvc22205, CSCvc22208, CSCvc88078, CSCvc88150, CSCvc88159, CSCvc88162, CSCvc88167.
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Analysis
by VulDB Data Team • 03/28/2023
The vulnerability described in CVE-2018-0303 represents a critical security flaw within the Cisco Discovery Protocol (CDP) implementation across multiple Cisco network devices. This weakness exists in the FXOS Software and NX-OS Software components, specifically affecting devices that have CDP configured and enabled. The vulnerability stems from inadequate validation of CDP packet headers, creating an exploitable condition that can be leveraged by adjacent attackers. The flaw falls under the Common Weakness Enumeration category CWE-121, which addresses stack-based buffer overflow conditions, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution.
The technical exploitation of this vulnerability occurs through the delivery of a specially crafted CDP packet to a Layer 2 adjacent device that has CDP enabled. When the affected device processes this malformed packet, insufficient input validation leads to a buffer overflow condition that can be leveraged to execute arbitrary code with root privileges. The attack vector requires physical or logical adjacency to the target device, making it a local privilege escalation vulnerability rather than a remote one. The buffer overflow can result in complete system compromise, allowing attackers to gain full administrative control over the affected network infrastructure. This represents a significant threat to network security as it targets fundamental network discovery protocols that are essential for device identification and network mapping.
The operational impact of this vulnerability extends across numerous Cisco product lines including Firepower series firewalls, MDS 9000 series switches, Nexus series switches across multiple platforms, and UCS fabric interconnects. The widespread affected device catalog indicates this vulnerability poses a substantial risk to enterprise network infrastructures, particularly in environments where multiple device types are interconnected. The potential for both arbitrary code execution and denial of service conditions creates a dual threat scenario that could severely disrupt network operations. Organizations running affected Cisco devices face the risk of complete network compromise, data exfiltration, and service disruption that could affect business continuity and regulatory compliance requirements.
Mitigation strategies for CVE-2018-0303 should prioritize immediate patching of affected devices through official Cisco software updates. Network administrators should implement network segmentation to limit adjacent access to critical devices and disable CDP where not essential for network operations. The implementation of network access control lists and monitoring for unusual CDP traffic patterns can help detect potential exploitation attempts. Organizations should also conduct comprehensive vulnerability assessments to identify all affected devices within their network infrastructure and prioritize remediation efforts based on risk assessment. The Cisco Bug IDs associated with this vulnerability indicate multiple related issues that were addressed through coordinated patch releases, emphasizing the importance of applying complete security updates rather than partial fixes. Security monitoring should include detection of malformed CDP packets and unusual device behavior that could indicate exploitation attempts.