CVE-2015-4323 in NX-OS
Summary
by MITRE
Buffer overflow in Cisco NX-OS on Nexus 1000V devices for VMware vSphere 7.3(0)ZN(0.9); Nexus 3000 devices 6.0(2)U5(1.41), 7.0(3)I2(0.373), and 7.3(0)ZN(0.83); Nexus 4000 devices 4.1(2)E1(1b); Nexus 7000 devices 6.2(14)S1; Nexus 9000 devices 7.3(0)ZN(0.9); and MDS 9000 devices 6.2 (13) and 7.1(0)ZN(91.99) and MDS SAN-OS 7.1(0)ZN(91.99) allows remote attackers to cause a denial of service (device outage) via a crafted ARP packet, related to incorrect MTU validation, aka Bug IDs CSCuv71933, CSCuv61341, CSCuv61321, CSCuu78074, CSCut37060, CSCuv61266, CSCuv61351, CSCuv61358, and CSCuv61366.
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Analysis
by VulDB Data Team • 06/12/2022
The vulnerability described in CVE-2015-4323 represents a critical buffer overflow condition affecting multiple Cisco networking devices running NX-OS software. This flaw specifically impacts Nexus 1000V virtual switches for VMware vSphere environments, Nexus 3000, 4000, 7000, and 9000 series physical switches, as well as MDS 9000 series storage area network switches. The vulnerability stems from improper validation of Maximum Transmission Unit (MTU) values within the handling of Address Resolution Protocol (ARP) packets, creating a scenario where maliciously crafted network traffic can trigger system instability.
The technical implementation of this vulnerability occurs when the affected devices process specially crafted ARP packets that contain oversized or malformed MTU values. According to CWE-121, this represents a classic stack-based buffer overflow condition where insufficient bounds checking allows an attacker to write data beyond the allocated buffer space. The flaw manifests in the network processing stack where ARP packet handling routines fail to properly validate incoming MTU parameters before processing, leading to memory corruption that can result in system crashes or complete device outages. The vulnerability affects specific software versions including NX-OS 7.3(0)ZN(0.9) for Nexus 1000V, 6.0(2)U5(1.41) and 7.0(3)I2(0.373) for Nexus 3000, and various other versions across the affected product lines.
From an operational perspective, this vulnerability presents a significant risk to network availability and business continuity. The remote exploit capability means that attackers can trigger denial of service conditions without requiring physical access or local network privileges, making it particularly dangerous in enterprise environments where network infrastructure reliability is paramount. The impact extends beyond individual device outages to potentially disrupt entire network segments, especially in virtualized environments where Nexus 1000V devices serve as virtual switching infrastructure for VMware vSphere deployments. The vulnerability affects devices in critical network infrastructure roles, making it a prime target for attackers seeking to cause widespread disruption. Organizations running affected Cisco equipment face potential service degradation or complete network outages that could impact business operations and customer access.
The security implications of this vulnerability align with ATT&CK technique T1499.004 for network denial of service attacks and T1071.004 for application layer protocol usage. Network administrators should implement immediate mitigations including applying the relevant Cisco security advisories and patches, implementing network segmentation to limit exposure, and monitoring for anomalous ARP traffic patterns. The vulnerability demonstrates the importance of proper input validation and bounds checking in network protocol implementations, highlighting how seemingly minor flaws in network processing can result in catastrophic system failures. Organizations should also consider network access control measures and intrusion detection systems to identify potential exploitation attempts. The affected devices require immediate patching to address the buffer overflow conditions, with Cisco releasing security updates specifically targeting these Bug IDs including CSCuv71933 and related identifiers, emphasizing the need for proactive security maintenance and vulnerability management programs across enterprise networking infrastructure.