Omron PLC CJ/CS/NJ Series CVE-2019-18261 Authentication Bypass Vulnerability

Description

Omron PLC CJ, CS and NJ Series are prone to an authentication-bypass vulnerability. An attacker can exploit this issue to bypass certain security restrictions and aid in brute-force attacks; other attacks may also be possible. The following products of Omron Programmable Logic Controllers are affected: Omron PLC CS series Omron PLC CJ series Omron PLC NJ series

Technologies Affected

• Omron PLC CJ series
• Omron PLC CS series
• Omron PLC NJ series

Recommendations

Block external access at the network boundary, unless external parties require service.
Filter access to the affected computer at the network boundary if global access isn’t needed. Restricting access to only trusted computers and networks might greatly reduce the likelihood of a successful exploit.

Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy a NID sensor between the network perimeter and the affected service. Flag on all requests that appear to be anomalous. Audit logs regularly for evidence of attacks.

Updates are available. Please see the references or vendor advisory for more information.