Unpatched Security Flaws Expose Mitsubishi Safety PLCs to Remote Attacks
Aug 05, 2021
Multiple unpatched security vulnerabilities have been disclosed in Mitsubishi safety programmable logic controllers (PLCs) that could be exploited by an adversary to acquire legitimate user names registered in the module via a brute-force attack, unauthorizedly login to the CPU module, and even cause a denial-of-service (DoS) condition. The security weaknesses, disclosed by Nozomi Networks , concern the implementation of an authentication mechanism in the MELSEC communication protocol that's used to communicate and exchange data with the target devices by reading and writing data to the CPU module. A quick summary of the flaws is listed below - Username Brute-force (CVE-2021-20594, CVSS score: 5.9) - Usernames used during authentication are effectively brute-forceable Anti-password Brute-force Functionality Leads to Overly Restrictive Account Lockout Mechanism (CVE-2021-20598, CVSS score: 3.7) - The implementation to thwart brute-force attacks not only blo...
