Living Inside the Command Line

  • 29/1/2022
  • One-minute read

Introduction

This post is to document the usage of Linux command line tools. Normal command line tools not security tools since security tools will have separate post.

Tools list:

  • lsof
  • ps
  • tar
  • socat (I’m really confused if this should be security or normal tool)

Socat

Socat is a unix tool, used for bidirectional communication, taking a simple look at man socat you will see a mountain of options, so lets keep it simple and compare it to something like netcat

TCP client

netcat

nc localhost 80

socat

socat TCP4:localhost:80
socat STDIN TCP4:localhost:80

TCP client with SSL

openssl

openssl s_client -connect server:443

socat

socat - OPENSSL:localhost:443

TCP server

netcat

nc -lp localhost 700

socat

socat TCP4-LISTEN:700 STDOUT

Spawn a Shell

netcat

nc -lp localhost 700 -e /bin/bash

socat

socat TCP4-LISTEN:700 EXEC:/bin/bash

TCP server with SSL

Generate certificate

openssl req -new -x509 -days 365 -nodes -out cert.pem -keyout cert.key

OpenSSL

openssl s_server -accept 8080 -key key.pem -cert cert.pem

socat

socat OPENSSL-LISTEN:443,cert=/cert.pem -
socat TCP4-LISTEN:5000,fork OPENSSL:localhost:443

Reverse proxy

Assuming there is a service listing on 127.0.0.1:8080 Acting as reverse proxy, redirecting all traffic hitting port 5000 to local connection 127.0.0.1:8080

socat TCP4-LISTEN:5000,fork TCP4:127.0.0.1:8080

Reference

Linux