Cisco IOS XR and NX-OS Software IPv6 Access Control List Bypass (CVE-2021-1389)

medium Tenable OT Security Plugin ID 501862

Synopsis

The remote OT asset is affected by a vulnerability.

Description

A vulnerability in the IPv6 traffic processing of Cisco IOS XR Software and Cisco NX-OS Software for certain Cisco devices could allow an unauthenticated, remote attacker to bypass an IPv6 access control list (ACL) that is configured for an interface of an affected device. The vulnerability is due to improper processing of IPv6 traffic that is sent through an affected device. An attacker could exploit this vulnerability by sending crafted IPv6 packets that traverse the affected device. A successful exploit could allow the attacker to access resources that would typically be protected by the interface ACL.

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

Solution

After upgrading a device to a fixed release of Cisco NX-OS Software, customers must apply the rule extension-header deny-all to any IPv6 ACL that is configured on the device. The rule is not enabled by default. A device should be considered vulnerable until the rule extension-header deny-all has been applied to all IPv6 ACLs that are configured on the device, even if it is running a fixed Cisco NX-OS Software release.

For more information, please refer to the vendor advisory.

Plugin Details

Severity: Medium

ID: 501862

Version: 1.2

Type: remote

Family: Tenable.ot

Published: 1/4/2024

Updated: 1/5/2024

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Low

Score: 2.5

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 4.7

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

CVSS Score Source: CVE-2021-1389

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

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

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: 2/4/2021

Vulnerability Publication Date: 2/4/2021

Reference Information

CVE: CVE-2021-1389

Detections

Analytics