The Omron FINS protocol has an authenticated feature to prevent access to memory regions. Authentication is susceptible to bruteforce attack, which may allow an adversary to gain access to protected memory. This access can allow overwrite of values including programmed logic.

An attacker with network access to the affected PLC (CJ-series and CS-series PLCs, all versions) may use a network protocol to read and write files on the PLC internal memory and memory card.