CyberSec Lab — Netcat

███╗ ██╗███████╗████████╗ ██████╗ █████╗ ████████╗ ████╗ ██║██╔════╝╚══██╔══╝██╔════╝██╔══██╗╚══██╔══╝ ██╔██╗ ██║█████╗ ██║ ██║ ███████║ ██║ ██║╚██╗██║██╔══╝ ██║ ██║ ██╔══██║ ██║ ██║ ╚████║███████╗ ██║ ╚██████╗██║ ██║ ██║

NC — NETCAT

THE SWISS ARMY KNIFE OF NETWORKING

MODULE 02 — BANNER GRABBING · LISTENERS · PORT CHECK · FILE TRANSFER

Opening raw TCP socket...

OBJECTIVES

Grab the SSH banner (port 22)

Grab the FTP banner (port 21)

Send a raw HTTP GET request

Check ports with nc -zv

Set up a listener with nc -lvnp

Catch a reverse shell connection

Transfer a file using netcat

Submit the pentest report

💻

Terminal

📡

Listener

📖

Reference

📝

Notepad

📋

Report

PENTEST ENGAGEMENT — AUTHORISED

NETCAT — THE SWISS ARMY KNIFE

TARGET: 10.10.15.150 — services.apexlab.local

SCENARIO

Nmap has confirmed several open ports on 10.10.15.150. Now use Netcat (nc) to manually interact with those services — grab banners, send raw requests, check ports, and demonstrate how nc can be used to receive a reverse shell and transfer files.

TARGET SERVICES

Port	Service
21/tcp	FTP — vsftpd
22/tcp	SSH — OpenSSH
80/tcp	HTTP — Apache
443/tcp	HTTPS
4444/tcp	Reserved for listener

PHASES

Phase 1 — Banner grabbing (SSH, FTP, HTTP)
Phase 2 — Raw HTTP request
Phase 3 — Port checking (-zv)
Phase 4 — Set up a listener
Phase 5 — Catch a reverse shell
Phase 6 — File transfer

HOW TO USE THE LISTENER PANEL

The Listener window simulates a second terminal — it shows what the receiving end of a netcat connection sees. Set up your listener there with nc -lvnp 4444, then from the main terminal connect back to simulate a reverse shell.

Display Mode

REFERENCE — NETCAT

BASIC SYNTAX

nc [options] [host] [port]

KEY FLAGS

Flag	Description
-l	Listen mode — wait for incoming connection
-v	Verbose — show connection details
-n	No DNS resolution (use IPs only)
-p [port]	Local port to listen on
-z	Zero-I/O mode — port scanning only
-u	UDP mode (default is TCP)
-w [sec]	Timeout for connections
-e [cmd]	Execute command on connect (ncat/older nc)

BANNER GRABBING

SSH banner

nc 10.10.15.150 22

FTP banner

nc 10.10.15.150 21

HTTP banner

nc 10.10.15.150 80

RAW HTTP REQUEST

Connect to port 80, then type the HTTP request manually:

nc 10.10.15.150 80
GET / HTTP/1.0
Host: 10.10.15.150
[press Enter twice]

PORT CHECKING

nc -zv 10.10.15.150 20-25

nc -zv 10.10.15.150 80 443 8080

LISTENER / REVERSE SHELL

Set up listener (in Listener panel)

nc -lvnp 4444

Trigger reverse shell (in main terminal)

nc 10.10.15.150 4444

FILE TRANSFER

Receiver side (listener)

nc -lvnp 4444 > received_file.txt

Sender side

nc 10.10.15.150 4444 < loot.txt

USEFUL COMBOS

nc -zv 10.10.15.150 1-1024 2>&1 | grep open

PENTEST REPORT — NETCAT RECON

BANNER GRABBING

Paste the exact version strings returned by the target services.

SSH VERSION STRING (port 22)

FTP VERSION STRING (port 21)

FILE TRANSFER FLAG

Complete the file transfer exercise to receive the flag, then paste it below.

FLAG