FTP

FTP connection has two channels

1. Control Channel (Port 21): For sending commands.

2. Data Channel (Port 20): For transferring files

FTP vs TFTP

• FTP (File Transfer Protocol): Uses TCP (reliable), supports authentication, encryption, and advanced features like creating/deleting files. Best for secure, complex file transfers.

• TFTP (Trivial File Transfer Protocol): Uses UDP (faster, less reliable), no authentication or encryption, only transfers files. Best for simple, quick tasks like booting devices.

Key Difference: FTP is secure and feature-rich; TFTP is fast and basic.

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download all file from ftp server

wget -m --no-passive <ftp://anonymous:anonymous@10.129.14.136>

With the PUT command, we can upload files in the current folder to the FTP server.

ftp> put testupload.txt

Setting	Description
listen=NO	Run from inetd or as a standalone daemon?
listen_ipv6=YES	Listen on IPv6 ?
anonymous_enable=NO	Enable Anonymous access?
local_enable=YES	Allow local users to login?
dirmessage_enable=YES	Display active directory messages when users go into certain directories?
use_localtime=YES	Use local time?
xferlog_enable=YES	Activate logging of uploads/downloads?
connect_from_port_20=YES	Connect from port 20?
secure_chroot_dir=/var/run/vsftpd/empty	Name of an empty directory
pam_service_name=vsftpd	This string is the name of the PAM service vsftpd will use.
rsa_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem	The last three options specify the location of the RSA certificate to use for SSL encrypted connections.

Restricting Users from Accessing FTP

The file /etc/ftpusers is used to block certain users from logging into the FTP server.

To view the blocked users, run:

cat /etc/ftpusers

To block a user (e.g., hacker), add them to the file:

echo "hacker" >> /etc/ftpusers

Manage service: systemctl restart vsftpd

try aggressive scan

nmap -sV -A -p 21 10.0.2.4

FTP

Command	Description
ftp <FQDN/IP>	Interact with the FTP service on the target.
nc -nv <FQDN/IP> 21	Interact with the FTP service on the target.
telnet <FQDN/IP> 21	Interact with the FTP service on the target.
openssl s_client -connect <FQDN/IP>:21 -starttls ftp	Interact with the FTP service on the target using encrypted connection.
wget -m --no-passive <ftp://anonymous>:anonymous@<target>	Download all available files on the target FTP server.