Kyocera » Fs-3830n : Security Vulnerabilities, CVEs,

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.

Kyocera 3830 (aka FS-3830N) printers have a back door that allows remote attackers to read and alter configuration settings via strings that begin with "!R!SIOP0", as demonstrated using (1) a connection to to TCP port 9100 or (2) the UNIX lp command.