FTP - 21

Files Transfer Protocol

• Client-Server protocol

• Clear text protocol

• Use of credentials or Anonymous FTP.

Check if the FTP server allows Anonymous Login

Credentials: anonymous:anonymous

Commands

Commands	Description
ls	Directory listing
ls -R	Recursive directory listing
put	Upload a file from local system to the FTP server
get	Download a file from the remote server to the local system

Active vs Passive mode

Active mode: The client tells the FTP server what port initiating the data communication to.

Source: cloudzy.com

Passive mode: The client will initiate the data communication to a port specified by the FTP server. Since the client initiates the data communication, it can circumvent firewall restrictions.

Source: cloudzy.com

Trivial File Transfer Protocol

• Does not require user authentication

• Simpler than FTP

• Works over UDP

Interaction with a FTP server with SSL/TLS encryption

 openssl s_client -connect 10.129.14.136:21 -starttls ftp

Uploading a file to the FTP server

ftp>passive
ftp>binary
ftp>put mondocument.txt

Download all files from a FTP server

wget -m --no-passive ftp://anonymous:anonymous@192.168.218.127

Enumerate Nmap scripts - FTP

Will enumerate all Nmap scripts related to FTP

find / -type f -name ftp* 2>/dev/null | grep scripts

Others element to check for

• Can you login with default or admin credentials?

• Does the FTP server allows anonymous authentication?

• Can you identify any exploit for the FTP server based upon the version/banner grabbing?

• Is the FTP server is the document root of the web application?

• Can you transfer files on the FTP share ? (upload/download)