Certain unspecified Kyocera printers have a default "admin" account with a blank password, which allows remote attackers to access an administrative menu via a telnet session.
https://exchange.xforce.ibmcloud.com/vulnerabilities/24774
http://www.vupen.com/english/advisories/2006/0620
http://secunia.com/advisories/18896
http://evader.wordpress.com/2006/02/16/kyocera-printers/
http://archives.neohapsis.com/archives/fulldisclosure/2006-02/0344.html