Hacking infoseclabs in peace.

There's been a lot of talk lately on the #infoseclabs channel about how to safely browse and interact with the lab.infoseclabs.net labs. I've gathered and modified a few scripts that will turn any Ubuntu VPS ( EC2, OVH, DigitalOcean) into a OpenVPN Server that will route all of your traffic through it, as well as configure SSH to allow Dynamic and Remote proxying from the VPS.  

The script to configure the server:

	#!/bin/bash
	###
	# Allow for ssh socks proxies and port forwarding
	###
	sed -i.bak 's/#GatewayPorts no/GatewayPorts yes #Proxy/g' /etc/sshd_config
	systemctl restartt ssh
	###
	# Script to set up OpenVPN for routing all traffic.
	# https://github.com/tinfoil/openvpn_autoconfig
	###
	set -e
	if [[ $EUID -ne 0 ]]; then
	echo "You must be a root user" 1>&2
	exit 1
	fi
	apt-get update -q
	debconf-set-selections <<EOF
	iptables-persistent iptables-persistent/autosave_v4 boolean true
	iptables-persistent iptables-persistent/autosave_v6 boolean true
	EOF
	apt-get install -qy openvpn curl iptables-persistent
	cd /etc/openvpn
	# Certificate Authority
	>ca-key.pem openssl genrsa 2048
	>ca-csr.pem openssl req -new -key ca-key.pem -subj /CN=OpenVPN-CA/
	>ca-cert.pem openssl x509 -req -in ca-csr.pem -signkey ca-key.pem -days 365
	>ca-cert.srl echo 01
	# Server Key & Certificate
	>server-key.pem openssl genrsa 2048
	>server-csr.pem openssl req -new -key server-key.pem -subj /CN=OpenVPN-Server/
	>server-cert.pem openssl x509 -req -in server-csr.pem -CA ca-cert.pem -CAkey ca-key.pem -days 365
	# Client Key & Certificate
	>client-key.pem openssl genrsa 2048
	>client-csr.pem openssl req -new -key client-key.pem -subj /CN=OpenVPN-Client/
	>client-cert.pem openssl x509 -req -in client-csr.pem -CA ca-cert.pem -CAkey ca-key.pem -days 365
	# Diffie hellman parameters
	>dh.pem openssl dhparam 2048
	chmod 600 *-key.pem
	# Set up IP forwarding and NAT for iptables
	>>/etc/sysctl.conf echo net.ipv4.ip_forward=1
	sysctl -p
	iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE
	>/etc/iptables/rules.v4 iptables-save
	# Write configuration files for client and server
	SERVER_IP=$(curl -s4 canhazip.com || echo "<insert server IP here>")
	>tcp443.conf cat <<EOF
	server 10.8.0.0 255.255.255.0
	verb 3
	duplicate-cn
	key server-key.pem
	ca ca-cert.pem
	cert server-cert.pem
	dh dh.pem
	keepalive 10 120
	persist-key yes
	persist-tun yes
	comp-lzo yes
	push "dhcp-option DNS 8.8.8.8"
	push "dhcp-option DNS 8.8.4.4"
	# Normally, the following command is sufficient.
	# However, it doesn't assign a gateway when using
	# VMware guest-only networking.
	#
	# push "redirect-gateway def1 bypass-dhcp"
	push "redirect-gateway bypass-dhcp"
	push "route-metric 512"
	push "route 0.0.0.0 0.0.0.0"
	user nobody
	group nogroup
	proto tcp
	port 443
	dev tun443
	status openvpn-status-443.log
	EOF
	>client.ovpn cat <<EOF
	client
	nobind
	dev tun
	redirect-gateway def1 bypass-dhcp
	remote $SERVER_IP 443 tcp
	comp-lzo yes
	<key>
	$(cat client-key.pem)
	</key>
	<cert>
	$(cat client-cert.pem)
	</cert>
	<ca>
	$(cat ca-cert.pem)
	</ca>
	EOF
	service openvpn restart
	cat client.ovpn
	cd -

view raw ConfigureSSHandOpenVPN.sh hosted with ❤ by GitHub

A wrapper script to easily setup reverse SSH tunnels:

	#!/usr/bin/env bash
	###
	# Wrapper script so I don't have to remeber all of the flags
	# if you want this to go smoothly use ssh-copy-id to copy your public key to the VPS
	###
	HOST="<Proxy IP>"
	USER="root"
	while getopts 'l:r:' flag; do
	case $flag in
	v ) verbose=true;;
	l ) local_port=$OPTARG;;
	r ) remote_port=$OPTARG;;
	esac
	done
	shift $(($OPTIND-1)); OPTIND=1
	usage="$(basename $0) -l <22> -r <19999>"
	if [[ -z $local_port || -z $remote_port ]]; then
	echo "$usage"
	exit 1
	fi
	cmd="ssh -f -N -T -R ${remote_port}:localhost:${local_port} ${USER}@${HOST}"
	trap "{ pkill -f \"$cmd\" ; exit 0 ; }" SIGINT
	x=0
	while true; do
	((x++))
	# if the ssh command isn't running, run it
	[ -z "$(pgrep -f "$cmd")" ] && $cmd
	sleep 30m
	# kill off the ssh connection every so often
	mod=$(($x%5))
	if [ $mod == 0 ]; then
	pkill -f "$cmd"
	sleep 10
	pkill -9 -f "$cmd"
	sleep 10
	fi
	done

view raw tunnel.sh hosted with ❤ by GitHub