Roger-Skyline-1

All operations were done on virtual box debian(10.1.0) in terminal. Google any command that you don't understand for more clearance

• In order to install all necessary utilities, run: apt-get install -y sudo net-tools iptables-persistent fail2ban sendmail apache2 cron

• Open /etc/ssh/sshd_config file using nano editor, change the lines as follows:

PasswordAuthentication yes

PermitRootLogin no

PubkeyAuthentication yes

• Open /etc/network/interfaces in nano editor, edit the file as follows:

#The loopback network interface

auto lo

iface lo inet loopback

allow-hotplug enp0s3

iface enp0s3 inet dhcp

allow-hotplug enp0s8


iface enp0s8 inet static

        address 192.168.56.3/30

• Make user as root, open /etc/passwd, find user name and change UID and GID to 0

• Run ssh-keygen, run cat ~/.ssh/id_rsa.pub and copy the entire contents.

• Make conection to the server: ssh <root-user>@debian -p 6969

• Create ssh directory mkdir .ssh

• Paste the key into .ssh/authorized_keys

• In the /etc/ssh/sshd_config change line as follows: PasswordAuthentication no

• Run sudo service ssh restart

• Run sudo nano /etc/network/if-pre-up.d/iptables and paste the following in order to set a firewall:

iptables-restore </etc/iptables.test.rules

iptables -F iptables -X iptables -t nat -F iptables -t nat -X iptables -t mangle -F iptables -t mangle -X

iptables -P INPUT DROP

iptables -P OUTPUT DROP

iptables -P FORWARD DROP

iptables -A INPUT -m conntrack -ctstate ESTABLISHED, RELATED -j ACCEPT

iptables -A INPUT -p tcp -i enp0s8 -dport 2222 -j ACCEPT

iptables -A INPUT -p tcp -i enp0s8 -dport 80 -j ACCEPT

iptables -A INPUT -p tcp -i enp0s8 -dport 443 -j ACCEPT

iptables -A OUTPUT -m conntrack! --ctstate INVALID -j ACCEPT

iptables -I INPUT -i lo -j ACCEPT

iptables -A INPUT -j LOG

iptables -A FORWARD -j LOG

iptables -I INPUT -p tcp -dport 80 -m connlimit -connlimit-above 10 -connlimit-mask 20 -j DROP

#port scan

iptables -N port-scanning

iptables -A port-scanning -p tcp --tcp-flags SYN,ACK,FIN,RST RST -m limit --limit 60/s --limit-burst 2 -j RETURN

iptables -A port-scanning -j DROP

• Change the permision of the file: sudo chmod +x /etc/network/if-pre-up.d/iptables

• The iptables rules are reset at each reboot. This file will allow the iptables-persistent package to load your rules every time you reboot. Modify port 6969 by the port of your ssh.

• Creates log and send info if files were changed and protects from ddos

sudo touch /var/log/apache2/server.log

• Run sudo nano /etc/fail2ban/jail.local and paste: [DEFAULT] destemail = USER@student.42.us.org sender = root@debian

• The same commamds in sudo nano/etc/cron.d/packages.sh

• Run sudo nano /etc/cron.d/survey.sh and paste :

then

echo "Crontab file has been modified" | sudo /usr/sbin/sendmail root

fi

• Run crontab -e

@reboot /etc/cron.d/packages.sh

0 0 * * * /etc/cron.d/survey.sh