CVE-2016-1465 in NX-OS
Summary
by MITRE
Cisco Nexus 1000v Application Virtual Switch (AVS) devices before 5.2(1)SV3(1.5i) allow remote attackers to cause a denial of service (ESXi hypervisor crash and purple screen) via a crafted Cisco Discovery Protocol packet that triggers an out-of-bounds memory access, aka Bug ID CSCuw57985.
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Analysis
by VulDB Data Team • 09/09/2022
The vulnerability identified as CVE-2016-1465 affects Cisco Nexus 1000v Application Virtual Switch devices operating on versions prior to 5.2(1)SV3(1.5i). This flaw represents a critical security weakness that enables remote attackers to execute a denial of service attack against ESXi hypervisor environments. The vulnerability manifests through a specially crafted Cisco Discovery Protocol packet that triggers an out-of-bounds memory access condition, ultimately leading to hypervisor crashes and the display of purple screens of death. The Cisco Discovery Protocol serves as a network protocol used by Cisco devices to share information about themselves with neighboring devices, making this attack vector particularly concerning for network infrastructure security.
The technical implementation of this vulnerability stems from inadequate input validation within the Cisco Nexus 1000v AVS software. When processing malformed Cisco Discovery Protocol packets, the system fails to properly bounds-check memory access operations, resulting in memory corruption that causes the ESXi hypervisor to become unstable. This memory access violation occurs during the processing of specific packet structures that contain crafted data fields, leading to unpredictable behavior in the hypervisor kernel. The vulnerability is classified as an out-of-bounds memory access issue, which aligns with CWE-125, a common weakness in software development where programs access memory locations outside of their allocated boundaries. The attack requires minimal privileges as it operates over the network, making it particularly dangerous for remote exploitation in virtualized environments.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromising entire virtualized infrastructures. When the ESXi hypervisor crashes, all virtual machines running on that host become unavailable, resulting in significant business disruption. The purple screen of death indicates a critical system failure that requires manual intervention to recover, including potential data loss and extended downtime for affected services. Organizations utilizing Cisco Nexus 1000v switches in their data centers face substantial risk as this vulnerability can be exploited remotely without authentication, making it an attractive target for attackers seeking to disrupt cloud services and virtualized applications. The vulnerability affects the core hypervisor functionality, which means that any virtual machines relying on the compromised switch will experience complete service interruption.
Mitigation strategies for CVE-2016-1465 primarily focus on immediate software updates and network segmentation measures. Organizations should prioritize upgrading their Cisco Nexus 1000v devices to versions 5.2(1)SV3(1.5i) or later, which contain patches addressing the memory access violation issue. Network administrators should also implement ingress filtering and access control lists to limit the exposure of affected devices to untrusted networks, as recommended by the ATT&CK framework's network infiltration techniques. Additionally, monitoring for unusual Cisco Discovery Protocol traffic patterns can help identify potential exploitation attempts. The vulnerability's classification as a remote code execution risk necessitates comprehensive network security monitoring and incident response procedures. Organizations should also consider implementing network segmentation strategies to isolate critical virtualized environments from potentially compromised network segments, thereby reducing the attack surface and limiting the potential impact of successful exploitation attempts.