Rockwell Automation Allen-Bradley Micrologix 1100 Improper Handling of Length Parameter Inconsistency (CVE-2020-6111)

high Tenable OT Security Plugin ID 500443

Synopsis

The remote OT asset is affected by a vulnerability.

Description

An exploitable denial-of-service vulnerability exists in the IPv4 functionality of Allen-Bradley MicroLogix 1100 Programmable Logic Controller Systems Series B FRN 16.000, Series B FRN 15.002, Series B FRN 15.000, Series B FRN 14.000, Series B FRN 13.000, Series B FRN 12.000, Series B FRN 11.000 and Series B FRN 10.000. A specially crafted packet can cause a major error, resulting in a denial of service. An attacker can send a malicious packet to trigger this vulnerability.

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

Solution

The following text was originally created by the Cybersecurity and Infrastructure Security Agency (CISA). The original can be found at CISA.gov.

Rockwell Automation recommends users of MicroLogix 1100 migrate to MicroLogix 1400 and apply firmware v21.006 or later.
Please see Rockwell Automation’s publication number, PN1548, for more information. Rockwell Automation recommends the following network-based vulnerability mitigations for embedded products:

- Utilize proper network infrastructure controls, such as firewalls, to help ensure traffic from unauthorized sources is blocked.
- Consult the product documentation for specific features, such as a hardware key mode setting, to which may be used to block unauthorized changes, etc.
- Block all traffic to EtherNet/IP or other CIP protocol-based devices from outside the manufacturing zone by blocking or restricting access to TCP and UDP Port 2222 and Port 44818 using proper network infrastructure controls, such as firewalls, UTM devices, or other security appliances. For more information on TCP/UDP ports used by Rockwell Automation products, see Knowledgebase Article ID BF7490

Rockwell Automation also recommends the following general mitigations:

- Minimize network exposure for all control system devices and/or systems and ensure they are not accessible from the Internet. For further information about the risks of unprotected Internet accessible control systems, please see Knowledgebase Article ID PN715
- Locate control system networks and devices behind firewalls and isolate them from the business network.
- When remote access is required, use secure methods, such as virtual private networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize a VPN is only as secure as the connected devices.

Plugin Details

Severity: High

ID: 500443

Version: 1.9

Type: remote

Family: Tenable.ot

Published: 2/7/2022

Updated: 3/4/2024

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

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

CVSS Score Source: CVE-2020-6111

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

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

Vulnerability Information

CPE: cpe:/o:rockwellautomation:micrologix_1100_b_firmware:10.000, cpe:/o:rockwellautomation:micrologix_1100_b_firmware:11.000, cpe:/o:rockwellautomation:micrologix_1100_b_firmware:12.000, cpe:/o:rockwellautomation:micrologix_1100_b_firmware:13.000, cpe:/o:rockwellautomation:micrologix_1100_b_firmware:14.000, cpe:/o:rockwellautomation:micrologix_1100_b_firmware:15.000, cpe:/o:rockwellautomation:micrologix_1100_b_firmware:15.002, cpe:/o:rockwellautomation:micrologix_1100_b_firmware:16.000

Required KB Items: Tenable.ot/Rockwell

Exploit Ease: No known exploits are available

Patch Publication Date: 12/3/2020

Vulnerability Publication Date: 12/3/2020

Reference Information

CVE: CVE-2020-6111

Detections

Analytics