The management interface in ZyNOS firmware 3.62(WK.6) on the Zyxel Zywall 2 device has a certain default password, which allows remote attackers to perform administrative actions.
https://exchange.xforce.ibmcloud.com/vulnerabilities/35914
http://www.securityfocus.com/archive/1/476031/100/0/threaded
http://www.louhi.fi/advisory/zyxel_070810.txt
http://securityreason.com/securityalert/3002