Why is FTP or Telnet an insecure protocol?
FTP and Telnet are insecure protocols because they use plain text authentication. This means that when you authenticate to the telnet or ftp server you send your login and password across the network un-encrypted or “in the clear”. In addition to sending the login and password in the clear telnet and ftp also send the data or payload in the clear as well. It is best to replace these insecure protocols with a more secure replacement such as SSH or SFTP (FTP over SSH). SSH encrypts the login and password as well as the data. SSH attempts to gain back some of the additional overhead of encryption by compressing the data at the same time.
