SSH Hardening Script

ssh-hardening.sh

#!/bin/bash
# SSH Hardenning Script
# Created By Dimas Restu Hidayanto (dimas.restu@student.upi.edu)

echo "--------------------------------------"
echo "SSH Hardening"
echo "dimas.restu@student.upi.edu"
echo "--------------------------------------"
echo ""

echo "Escalating Privilage..."
echo "Checking escalation privilage."
if [ $UID != 0 ]; then
  echo "Sorry. Only the ROOT user can run this program!"
  echo "[FAILED]"
  exit 0
fi
echo "[DONE]"
echo ""


echo "SSH Policies Hardening..."

echo " - Backing-up current configuration file."
cp /etc/ssh/sshd_config /etc/ssh/sshd_config.backup

echo " - Changing value Protocol to 2."
if [ $(cat /etc/ssh/sshd_config | grep Protocol | wc -l) -eq 0 ]; then
  echo "Protocol 2" >> /etc/ssh/sshd_config
else
  sed -i -e '1,/#Protocol [a-zA-Z0-9]*/s/#Protocol [a-zA-Z0-9]*/Protocol 2/' /etc/ssh/sshd_config
  sed -i -e '1,/Protocol [a-zA-Z0-9]*/s/Protocol [a-zA-Z0-9]*/Protocol 2/' /etc/ssh/sshd_config
fi

echo " - Changing value PermitUserEnvironment to no."
if [ $(cat /etc/ssh/sshd_config | grep PermitUserEnvironment | wc -l) -eq 0 ]; then
  echo "PermitUserEnvironment no" >> /etc/ssh/sshd_config
else
  sed -i -e '1,/#PermitUserEnvironment [a-zA-Z0-9]*/s/#PermitUserEnvironment [a-zA-Z0-9]*/PermitUserEnvironment no/' /etc/ssh/sshd_config
  sed -i -e '1,/PermitUserEnvironment [a-zA-Z0-9]*/s/PermitUserEnvironment [a-zA-Z0-9]*/PermitUserEnvironment no/' /etc/ssh/sshd_config
fi

echo " - Changing value PermitEmptyPasswords to No."
if [ $(cat /etc/ssh/sshd_config | grep PermitEmptyPasswords | wc -l) -eq 0 ]; then
  echo "PermitEmptyPasswords no" >> /etc/ssh/sshd_config
else
  sed -i -e '1,/#PermitEmptyPasswords [a-zA-Z0-9]*/s/#PermitEmptyPasswords [a-zA-Z0-9]*/PermitEmptyPasswords no/' /etc/ssh/sshd_config
  sed -i -e '1,/PermitEmptyPasswords [a-zA-Z0-9]*/s/PermitEmptyPasswords [a-zA-Z0-9]*/PermitEmptyPasswords no/' /etc/ssh/sshd_config
fi

echo " - Changing value MaxAuthTries to 6."
if [ $(cat /etc/ssh/sshd_config | grep MaxAuthTries | wc -l) -eq 0 ]; then
  echo "MaxAuthTries 6" >> /etc/ssh/sshd_config
else
  sed -i -e '1,/#MaxAuthTries [a-zA-Z0-9]*/s/#MaxAuthTries [a-zA-Z0-9]*/MaxAuthTries 6/' /etc/ssh/sshd_config
  sed -i -e '1,/MaxAuthTries [a-zA-Z0-9]*/s/MaxAuthTries [a-zA-Z0-9]*/MaxAuthTries 6/' /etc/ssh/sshd_config
fi

echo " - Changing value LoginGraceTime to 2m."
if [ $(cat /etc/ssh/sshd_config | grep LoginGraceTime | wc -l) -eq 0 ]; then
  echo "LoginGraceTime 2m" >> /etc/ssh/sshd_config
else
  sed -i -e '1,/#LoginGraceTime [a-zA-Z0-9]*/s/#LoginGraceTime [a-zA-Z0-9]*/LoginGraceTime 2m/' /etc/ssh/sshd_config
  sed -i -e '1,/LoginGraceTime [a-zA-Z0-9]*/s/LoginGraceTime [a-zA-Z0-9]*/LoginGraceTime 2m/' /etc/ssh/sshd_config
fi

echo " - Changing value ClientAliveInterval to 2m."
if [ $(cat /etc/ssh/sshd_config | grep ClientAliveInterval | wc -l) -eq 0 ]; then
  echo "ClientAliveInterval 2m" >> /etc/ssh/sshd_config
else
  sed -i -e '1,/#ClientAliveInterval [a-zA-Z0-9]*/s/#ClientAliveInterval [a-zA-Z0-9]*/ClientAliveInterval 2m/' /etc/ssh/sshd_config
  sed -i -e '1,/ClientAliveInterval [a-zA-Z0-9]*/s/ClientAliveInterval [a-zA-Z0-9]*/ClientAliveInterval 2m/' /etc/ssh/sshd_config
fi

echo " - Changing value LogLevel to VERBOSE."
if [ $(cat /etc/ssh/sshd_config | grep LogLevel | wc -l) -eq 0 ]; then
  echo "LogLevel VERBOSE" >> /etc/ssh/sshd_config
else
  sed -i -e '1,/#LogLevel [a-zA-Z0-9]*/s/#LogLevel [a-zA-Z0-9]*/LogLevel VERBOSE/' /etc/ssh/sshd_config
  sed -i -e '1,/LogLevel [a-zA-Z0-9]*/s/LogLevel [a-zA-Z0-9]*/LogLevel VERBOSE/' /etc/ssh/sshd_config
fi

echo " - Changing value PrintLastLog to yes."
if [ $(cat /etc/ssh/sshd_config | grep PrintLastLog | wc -l) -eq 0 ]; then
  echo "PrintLastLog yes" >> /etc/ssh/sshd_config
else
  sed -i -e '1,/#PrintLastLog [a-zA-Z0-9]*/s/#PrintLastLog [a-zA-Z0-9]*/PrintLastLog yes/' /etc/ssh/sshd_config
  sed -i -e '1,/PrintLastLog [a-zA-Z0-9]*/s/PrintLastLog [a-zA-Z0-9]*/PrintLastLog yes/' /etc/ssh/sshd_config
fi

echo " - Changing value AllowTcpForwarding to no."
if [ $(cat /etc/ssh/sshd_config | grep AllowTcpForwarding | wc -l) -eq 0 ]; then
  echo "AllowTcpForwarding no" >> /etc/ssh/sshd_config
else
  sed -i -e '1,/#AllowTcpForwarding [a-zA-Z0-9]*/s/#AllowTcpForwarding [a-zA-Z0-9]*/AllowTcpForwarding no/' /etc/ssh/sshd_config
  sed -i -e '1,/AllowTcpForwarding [a-zA-Z0-9]*/s/AllowTcpForwarding [a-zA-Z0-9]*/AllowTcpForwarding no/' /etc/ssh/sshd_config
fi

echo " - Changing value X11Forwarding to no."
if [ $(cat /etc/ssh/sshd_config | grep X11Forwarding | wc -l) -eq 0 ]; then
  echo "X11Forwarding no" >> /etc/ssh/sshd_config
else
  sed -i -e '1,/#X11Forwarding [a-zA-Z0-9]*/s/#X11Forwarding [a-zA-Z0-9]*/X11Forwarding no/' /etc/ssh/sshd_config
  sed -i -e '1,/X11Forwarding [a-zA-Z0-9]*/s/X11Forwarding [a-zA-Z0-9]*/X11Forwarding no/' /etc/ssh/sshd_config
fi

echo " - Changing SSH Daemon Configuraion File Permissions."
chmod 600 /etc/ssh/sshd_config

echo " - Restarting SSH Daemon."
systemctl restart sshd

echo "[DONE]"
exit 0