CVE-2015-6260 in NX-OS
Summary
by MITRE
Cisco NX-OS 7.1(1)N1(1) on Nexus 5500, 5600, and 6000 devices does not properly validate PDUs in SNMP packets, which allows remote attackers to cause a denial of service (SNMP application restart) via a crafted packet, aka Bug ID CSCut84645.
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Analysis
by VulDB Data Team • 07/08/2022
The vulnerability identified as CVE-2015-6260 affects Cisco NX-OS software version 7.1(1)N1(1) running on Nexus 5500, 5600, and 6000 series switches. This represents a critical security flaw in the SNMP implementation that can be exploited by remote attackers to disrupt network operations. The issue stems from insufficient validation mechanisms within the SNMP protocol data unit (PDU) processing functionality, creating a pathway for malicious actors to manipulate the system's SNMP application.
The technical flaw manifests in the improper validation of SNMP PDUs received by the affected Cisco Nexus devices. When processing crafted SNMP packets, the system fails to adequately validate the structure and content of received PDUs, allowing specially constructed malicious packets to trigger unexpected behavior within the SNMP application layer. This validation failure occurs at the protocol parsing level where the system does not properly check the integrity and legitimacy of incoming SNMP messages before processing them. The vulnerability specifically impacts the SNMP application restart functionality, causing the service to terminate unexpectedly and requiring manual intervention or automatic restart to restore normal operations.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged to create persistent denial of service conditions that may affect network monitoring and management capabilities. Network administrators relying on SNMP for device monitoring, configuration management, and performance tracking could experience complete loss of visibility into affected switches. The vulnerability is particularly concerning in enterprise environments where SNMP is extensively used for network operations center (NOC) monitoring, as it could provide attackers with a reliable method to disrupt critical network infrastructure management functions. This type of attack can be executed remotely without requiring authentication credentials, making it accessible to any attacker with network access to the affected devices.
Organizations should implement immediate mitigations including applying the relevant Cisco security patches and updates that address the SNMP validation issues in NX-OS software. Network segmentation and access control measures should be enhanced to limit exposure of affected devices to untrusted networks. The vulnerability aligns with CWE-129, which addresses improper validation of input, and can be mapped to ATT&CK technique T1499.004 for network denial of service attacks. Additional protective measures include implementing SNMP access control lists, disabling SNMPv1 and SNMPv2c if SNMPv3 is available, and monitoring network traffic for suspicious SNMP packet patterns. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar issues across the network infrastructure.