Security researcher discovered thousands of Lantronix Serial-to-Ethernet devices connected online that leak Telnet passwords. Hackers can use the leaked passwords to launch cyber attacks against the equipment that is connected to them. Devices are widely adopted in to give connectivity to ICS (Industrial Control Systems) Most of them are very old equipment that only comes with serial ports. An attacker can take over the device via Telnet and use the privileged access to send serial commands to the connected devices.”]
Source: http://securityaffairs.co/wordpress/66275/hacking/lantronix-serial-to-ethernet-leakage.html