The Linux firmware image on (1) Korenix Jetport 5600 series serial-device servers and (2) ORing Industrial DIN-Rail serial-device servers has a hardcoded password of "password" for the root account, which allows remote attackers to obtain administrative access via an SSH session.
https://exchange.xforce.ibmcloud.com/vulnerabilities/77992
http://www.securityfocus.com/bid/55196
http://www.digitalbond.com/2012/06/13/korenix-and-oring-insecurity