Cisco NX-OS Software VXLAN OAM Denial of Service (CVE-2021-1587)

high Tenable OT Security Plugin ID 501863

Synopsis

The remote OT asset is affected by a vulnerability.

Description

A vulnerability in the VXLAN Operation, Administration, and Maintenance (OAM) feature of Cisco NX-OS Software, known as NGOAM, could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of specific packets with a Transparent Interconnection of Lots of Links (TRILL) OAM EtherType. An attacker could exploit this vulnerability by sending crafted packets, including the TRILL OAM EtherType of 0x8902, to a device that is part of a VXLAN Ethernet VPN (EVPN) fabric. A successful exploit could allow the attacker to cause an affected device to experience high CPU usage and consume excessive system resources, which may result in overall control plane instability and cause the affected device to reload.
Note: The NGOAM feature is disabled by default.

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.

Solution

Disabling the NGOAM feature removes the exploit vector. Administrators can disable the NGOAM feature by using the no feature ngoam command at the Cisco NX-OS CLI in global configuration mode. This action may be a suitable mitigation for affected devices that do not require use of this feature until they can be upgraded.

For more information, please refer to the vendor advisory.

Plugin Details

Severity: High

ID: 501863

Version: 1.2

Type: remote

Family: Tenable.ot

Published: 1/4/2024

Updated: 4/22/2024

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.3

Temporal Score: 3.2

Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:P

CVSS Score Source: CVE-2021-1587

CVSS v3

Risk Factor: High

Base Score: 8.6

Temporal Score: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:cisco:nx-os:-

Required KB Items: Tenable.ot/Cisco

Exploit Ease: No known exploits are available

Patch Publication Date: 8/25/2021

Vulnerability Publication Date: 8/25/2021

Reference Information

CVE: CVE-2021-1587

CWE: 436

Detections

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