Rockwell Automation CompactLogix 5370 and ControlLogix 5570 Controllers (Update A)

1. EXECUTIVE SUMMARY

• CVSS v3 5.8
• ATTENTION: Exploitable remotely/low skill level to exploit
• Vendor: Rockwell Automation
• Equipment: CompactLogix and ControlLogix controllers
• Vulnerability: Improper Input Validation

2. UPDATE INFORMATION

This updated advisory is a follow-up to the original advisory titled ICSA-21-061-02 Rockwell Automation CompactLogix 5370 and ControlLogix 5570 Controllers that was published March 2, 2021, to the ICS webpage on us-cert.cisa.gov.

3. RISK EVALUATION

Successful exploitation of this vulnerability may allow an attacker to send specially crafted CIP packet requests to a controller, which may cause denial-of-service conditions in communications with other products.

4. TECHNICAL DETAILS

4.1 AFFECTED PRODUCTS

The following versions of Rockwell Automation devices are affected:

• Armor Compact GuardLogix 5370 controllers, Versions 33 and prior
• Armor GuardLogix, Safety Controllers, Versions 33 and prior
• CompactLogix 5370 L1 controllers, Versions 33 and prior
• CompactLogix 5370 L2 controllers, Versions 33 and prior
• CompactLogix 5370 L3 controllers, Versions 33 and prior
• Compact GuardLogix 5370 controllers, Versions 33 and prior
• ControlLogix 5570 controllers, Versions 33 and prior

4.2 VULNERABILITY OVERVIEW

4.2.1    IMPROPER INPUT VALIDATION CWE-22

The connection establishment algorithm found in CompactLogix 5370 and ControlLogix 5570 does not sufficiently manage its control flow during execution, creating an infinite loop. This may allow an attacker to send specially crafted CIP packet requests to a controller, which may cause denial-of-service conditions in communications with other products.

CVE-2020-6998 has been assigned to this vulnerability. A CVSS v3 base score of 5.8 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L).

4.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: United States

4.4 RESEARCHER

Yeop Chang reported this vulnerability to CISA.

5. MITIGATIONS

Rockwell Automation recommends affected users apply firmware v33.011 or later.

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For more information see the Rockwell Automation advisory (login required).

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CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

• Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
• Locate control system networks and remote 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 VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.



CISA also provides a section for control systems security recommended practices on the ICS webpage on us-cert.cisa.gov. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage on us-cert.cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.



Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents.

No known public exploits specifically target this vulnerability.