Automation Direct CLICK PLC CPU Modules: C0-1x CPUs with firmware prior to v3.00 does not protect against additional software programming connections. An attacker can connect to the PLC while an existing connection is already active.

The programming protocol allows for a previously entered password and lock state to be read by an attacker. If the previously entered password was successful, the attacker can then use the password to unlock Automation Direct CLICK PLC CPU Modules: C0-1x CPUs with firmware prior to v3.00.

All programming connections receive the same unlocked privileges, which can result in a privilege escalation. During the time Automation Direct CLICK PLC CPU Modules: C0-1x CPUs with firmware prior to v3.00 is unlocked by an authorized user, an attacker can connect to the PLC and read the project without authorization.

After Automation Direct CLICK PLC CPU Modules: C0-1x CPUs with firmware prior to v3.00 is unlocked by an authorized user, the unlocked state does not timeout. If the programming software is interrupted, the PLC remains unlocked. All subsequent programming connections are allowed without authorization. The PLC is only relocked by a power cycle, or when the programming software disconnects correctly.

Automation Direct CLICK PLC CPU Modules: C0-1x CPUs with firmware prior to v3.00 passwords are sent as plaintext during unlocking and project transfers. An attacker who has network visibility can observe the password exchange.