I'm looking at an IP range as a part of a project and discovered several FTP server. They all run vsftpd (3.0.2) on port 21.
I do not have login credentials and anonymous logins are disabled. Can I somehow identify whether the server would encrypt the actual file transfer (e.g. FTPS/SFTP) or not (Plaintext FTP)?
As suggested by Moonsik Park, I've attempted to identify the used protocol. My result differs from the suggestion, as it seems that I can't use
AUTH TLS before authentication.
telnet <TARGET-IP> 21 Trying <TARGET-IP>... Connected to <TARGET-IP>. Escape character is '^]'. 220 (vsFTPd 3.0.2) AUTH TLS 530 Please login with USER and PASS.
edit2: The same applies to vsFTPd 3.0.3. The default configuration has SSL disabled, but I'm yet to find out how I can identify this as an unauthenticated user.