FTP

Legacy FTP does not use encryption or integrity validation. A more secure protocol should be used like FTPS (File Transfer Protocol Secure) or SFTP (Secure File Transfer Protocol).

These use encryption, but some variations like Blowfish and DES use weak encryption ciphers. To verify file integrity, SFTP uses SSH, and FTPS uses FTP over TLS. By default, FTP servers often allow anonymous authentication which can be exploited by attackers.