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1. EXECUTIVE SUMMARY
- CVSS v3 10.0
- ATTENTION: Exploitable remotely/low skill level to exploit.
- Vendor: Rockwell
- Equipment: MicroLogix Controller
- Vulnerabilities: Improper Authentication
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could cause denial of service, disclosure of sensitive information, communication loss, and modification of settings or ladder logic.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of MicroLogix Controllers, a PLC (Programmable Logic Controller), are affected:
- MicroLogix 1400 Versions FRN 21.003 and prior, and
- MicroLogix 1100 Versions FRN 16.00 and prior.
3.2 VULNERABILITY OVERVIEW
A remote, unauthenticated attacker could send a specially crafted packet to the Ethernet port of an affected controller, which puts the device in a fault state, and could result in the deletion of ladder logic.
A remote, unauthenticated attacker could send a specially crafted packet that does not indicate the download is complete to the controller during the standard download process, causing the controller to freeze for one minute before entering a fault state.
A specially crafted SNMP-set request, when sent without associated SNMP-set commands for firmware flashing, can cause the device to power cycle, resulting in downtime for the device.
A remote, unauthenticated attacker could send a specially crafted packet to the affected device and utilize read or write operations. This could result in several potential impacts, ranging from disclosure of sensitive information, modification of settings, or ladder logic modification.
See the Rockwell customer notification for the table with specific CVEs. A CVSS v3 base score of 10.0 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H).
A memory module, which is a backup, installed in a MicroLogix controller allows a user to instruct the controller to write to its program to the module without authentication.
The MicroLogix 1400 controller supports 10 active sessions at a time. An attacker could send their own registered session packets; and once the 11th packet is sent, the first packet will be dropped and the user session will be lost.
- Critical Infrastructure Sectors: Critical Manufacturing, Food and Agriculture, and Water and Wastewater Systems.
- Countries/Areas Deployed: Worldwide
- Company Headquarters Location: Wisconsin
Jared Rittle and Patrick DeSantis of Cisco reported these vulnerabilities to Rockwell, and Rockwell reported the vulnerabilities to NCCIC.
Rockwell Automation has recommended that users employ the following mitigation strategies where applicable:
- Users using affected versions of MicroLogix 1100 and MicroLogix 1400 Series A are urged to contact their local distributor or Sales Office in order to upgrade their devices to a newer product line.
- Set keyswitch to Hard Run to block any unauthorized changes
- For MicroLogix 1400 Series only, Apply FRN 21.002 or later
Rockwell Automation has provided more specific mitigations that can be found in their customer notification (KB1072942) located at:
NCCIC recommends that users take defensive measures to minimize the risk of exploitation of these vulnerabilities. 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 that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the connected devices.
NCCIC reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
NCCIC also provides a section for control systems security recommended practices on the ICS-CERT web page. 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 in the ICS‑CERT Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies, that is available for download from the ICS-CERT website.
No known public exploits specifically target these vulnerabilities.
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