Easy-Guacamole-Installer/guac-optional-features/add-fail2ban.sh
2024-12-07 17:28:12 +11:00

294 lines
10 KiB
Bash

#!/bin/bash
#######################################################################################################################
# Add fail2ban restrictions to Guacamole
# For Ubuntu / Debian / Raspbian
# David Harrop
# December 2024
#######################################################################################################################
# Prepare text output colours
GREY='\033[0;37m'
DGREY='\033[0;90m'
GREYB='\033[1;37m'
LRED='\033[0;91m'
LGREEN='\033[0;92m'
LYELLOW='\033[0;93m'
NC='\033[0m' #No Colour
clear
# Check if user is root or sudo
if ! [[ $(id -u) = 0 ]]; then
echo
echo -e "${LGREEN}Please run this script as sudo or root${NC}" 1>&2
echo
exit 1
fi
# Initialise variables
FAIL2BAN_BASE=""
FAIL2BAN_GUAC=""
FAIL2BAN_NGINX=""
FAIL2BAN_SSH=""
TOMCAT_VERSION=$(ls /etc/ | grep tomcat)
TOMCAT_SERVICE_FILE="/usr/lib/systemd/system/$TOMCAT_VERSION.service"
# Tomcat service file logging lines that must exist
OUTPUT_LINE="StandardOutput=append:/var/log/$TOMCAT_VERSION/catalina.out"
ERROR_LINE="StandardError=append:/var/log/$TOMCAT_VERSION/catalina.out"
#Clean up from any previous runs
rm -f /tmp/fail2ban.temp1
rm -f /tmp/fail2ban.temp2
rm -f /tmp/ip_list.txt
rm -f /tmp/netaddr.txt
#######################################################################################################################
# Start setup prompts #################################################################################################
#######################################################################################################################
# Prompt to install fail2ban base package with no policy as yet, default of yes
if [[ -z ${FAIL2BAN_BASE} ]]; then
echo
echo -e -n "${LGREEN}Install Fail2ban base package? [default y]: ${GREY}"
read PROMPT
if [[ ${PROMPT} =~ ^[Nn]$ ]]; then
FAIL2BAN_BASE=false
else
FAIL2BAN_BASE=true
fi
fi
# Prompt to install Guacamole fail2ban config defaults, default of no
if [[ -z ${FAIL2BAN_GUAC} ]] && [[ "${FAIL2BAN_BASE}" = true ]]; then
echo -e -n "${GREY}POLICY: Apply Guacamole fail2ban security policy? (Y/n) [default y]:${GREY}"
read PROMPT
if [[ ${PROMPT} =~ ^[Nn]$ ]]; then
FAIL2BAN_GUAC=false
else
FAIL2BAN_GUAC=true
fi
fi
# Prompt to install Nginx fail2ban config defaults , default of no - NOT IMPLEMENTED YET
#if [[ -z ${FAIL2BAN_NGINX} ]] && [[ "${FAIL2BAN_BASE}" = true ]]; then
# echo -e -n "${GREY}POLICY: Apply Nginx fail2ban security policy? (y/n) [default n]:${GREY}"
# read PROMPT
# if [[ ${PROMPT} =~ ^[Yy]$ ]]; then
# FAIL2BAN_NGINX=true
# else
# FAIL2BAN_NGINX=false
# fi
#fi
# Prompt to install SSH fail2ban config defaults , default of no - NOT IMPLEMENTED YET
#if [[ -z ${FAIL2BAN_SSH} ]] && [[ "${FAIL2BAN_BASE}" = true ]]; then
# echo -e -n "${GREY}POLICY: Apply SSH fail2ban security policy? (y/n) [default n]:${GREY}"
# read PROMPT
# if [[ ${PROMPT} =~ ^[Yy]$ ]]; then
# FAIL2BAN_SSH=true
# else
# FAIL2BAN_SSH=false
# fi
#fi
#######################################################################################################################
# Fail2ban base setup #################################################################################################
#######################################################################################################################
# Install base fail2ban base application, and whitelist the local subnet as the starting baseline (no policy defined yet)
if [[ "${FAIL2BAN_BASE}" = true ]]; then
echo
#Update and install fail2ban (and john for management of config file updates, and not overwrite any existing settings)
apt-get update -qq
apt-get install fail2ban john -qq -y
# Create the basic jail.local template local subnet whitelist
echo
cat >/tmp/fail2ban.temp1 <<EOF
[DEFAULT]
destemail = yourname@example.com
sender = yourname@example.com
action = %(action_mwl)s
ignoreip =
[sshd]
backend = systemd
enabled = true
EOF
# We need to discover all interfaces to ascertain what network ranges to add to fail2ban "ignoreip" policy override defaults
ip -o addr show up primary scope global | while read -r num dev fam addr rest; do echo ${addr%*}; done | cat >/tmp/ip_list.txt
# Loop the list of discovered ips and extract the subnet ID addresses for each interface
FILE=/tmp/ip_list.txt
LINES=$(cat $FILE)
for LINE in $LINES; do
tonum() {
if [[ $LINE =~ ([[:digit:]]+)\.([[:digit:]]+)\.([[:digit:]]+)\.([[:digit:]]+) ]]; then
addr=$(((${BASH_REMATCH[1]} << 24) + (${BASH_REMATCH[2]} << 16) + (${BASH_REMATCH[3]} << 8) + ${BASH_REMATCH[4]}))
eval "$2=\$addr"
fi
}
toaddr() {
b1=$((($1 & 0xFF000000) >> 24))
b2=$((($1 & 0xFF0000) >> 16))
b3=$((($1 & 0xFF00) >> 8))
b4=$(($1 & 0xFF))
eval "$2=\$b1.\$b2.\$b3.\$b4"
}
if [[ $LINE =~ ^([0-9\.]+)/([0-9]+)$ ]]; then
# CIDR notation
IPADDR=${BASH_REMATCH[1]}
NETMASKLEN=${BASH_REMATCH[2]}
PREFIX=$NETMASKLEN
zeros=$((32 - NETMASKLEN))
NETMASKNUM=0
for ((i = 0; i < $zeros; i++)); do
NETMASKNUM=$(((NETMASKNUM << 1) ^ 1))
done
NETMASKNUM=$((NETMASKNUM ^ 0xFFFFFFFF))
toaddr $NETMASKNUM NETMASK
else
IPADDR=${1:-192.168.1.1}
NETMASK=${2:-255.255.255.0}
fi
tonum $IPADDR IPADDRNUM
tonum $NETMASK NETMASKNUM
# The logic to calculate network and broadcast
INVNETMASKNUM=$((0xFFFFFFFF ^ NETMASKNUM))
NETWORKNUM=$((IPADDRNUM & NETMASKNUM))
BROADCASTNUM=$((INVNETMASKNUM | NETWORKNUM))
toaddr $NETWORKNUM NETWORK
toaddr $BROADCASTNUM BROADCAST
# Reverse engineer the subnet ID from the calcualted IP address and subnet prefix
IFS=. read -r i1 i2 i3 i4 <<<"$IPADDR"
IFS=. read -r m1 m2 m3 m4 <<<"$NETMASK"
# Lay out the subnet ID address as a variable
printf -v NETADDR "%d.%d.%d.%d" "$((i1 & m1))" "$((i2 & m2))" "$((i3 & m3))" "$((i4 & m4))"
#Dump out the calcualted subnet IDs to a file
echo $NETADDR"/"$NETMASKLEN | tr '\n' ' ' | cat >>/tmp/netaddr.txt
done
fi
if [[ "${FAIL2BAN_BASE}" = true ]]; then
# Now the above loop is done, append the single loopback address to all the discovered the subnet IDs in a single line
sed -i 's/^/127.0.0.1\/24 /' /tmp/netaddr.txt
# Finally assemble the entire syntax of the ignoreip whitelist for insertion into the base fail2ban config
SED_IGNORE=$(echo "ignoreip = ")
SED_NETADDR=$(cat /tmp/netaddr.txt)
sed -i "s|ignoreip \=|${SED_IGNORE}${SED_NETADDR}|g" /tmp/fail2ban.temp1
# Move the new base fail2ban config to the jail.local file
touch /etc/fail2ban/jail.local
# Apply the base config, keeping any pre-existing settings
sudo bash -c 'cat /tmp/fail2ban.temp1 > /etc/fail2ban/jail.local'
# bounce the service to reload the new config
systemctl restart fail2ban
# Display the new config
echo "New base /etc/fail2ban/jail.local config:"
cat /etc/fail2ban/jail.local
echo
echo -e "${LGREEN}Fail2ban base installed...${GREY}"
echo
else
echo -e "${LGREEN}Fail2ban setup cancelled.${GREY}"
fi
#######################################################################################################################
# Fail2ban optional policy setup items ################################################################################
#######################################################################################################################
if [[ "${FAIL2BAN_GUAC}" = true ]]; then
# Create the Guacamole jail.local policy template
cat >/tmp/fail2ban.temp2 <<EOF
[guacamole]
enabled = true
port = http,https
logpath = /var/log/$TOMCAT_VERSION/catalina.out
bantime = 10m
findtime = 60m
maxretry = 5
EOF
# Apply the new Guacamole jail config
sudo bash -c 'cat /tmp/fail2ban.temp2 >> /etc/fail2ban/jail.local'
# Backup the default Fail2ban Guacamole filter
cp /etc/fail2ban/filter.d/guacamole.conf /etc/fail2ban/filter.d/guacamole.conf.bak
# Remove the default log search regex
sudo bash -c 'sed -e "/Authentication attempt from/ s/^#*/#/" -i /etc/fail2ban/filter.d/guacamole.conf'
# Create a new log search regex specific for tomcat logs (as a variable due to complexity of characters for sed syntax)
REGEX='failregex = ^.*WARN o\.a\.g\.r\.auth\.AuthenticationService - Authentication attempt from <HOST> for user "[^"]*" failed\.$'
#Insert the new regex
sed -i -e "/Authentication attempt from/a ${REGEX}" /etc/fail2ban/filter.d/guacamole.conf
fi
# Clean up
rm -f /tmp/fail2ban.temp1
rm -f /tmp/fail2ban.temp2
rm -f /tmp/ip_list.txt
rm -f /tmp/netaddr.txt
apt-get -y remove john > /dev/null 2>&1
apt-get -y autoremove > /dev/null 2>&1
# Display the updated config
echo "Updated jail.local with Guacamole filter policy:"
cat /etc/fail2ban/jail.local
# make sure Tomcat catalina logs are configured
if [[ ! -f "$TOMCAT_SERVICE_FILE" ]]; then
echo "Error: $TOMCAT_SERVICE_FILE not found, exiting..."
exit 1
else
if grep -q "^$OUTPUT_LINE" "$TOMCAT_SERVICE_FILE" && grep -q "^$ERROR_LINE" "$TOMCAT_SERVICE_FILE"; then
echo "Required lines already exist in $TOMCAT_SERVICE_FILE. No changes made."
else
# Add lines if they don't already exist
sed -i "/^\[Service\]/a $OUTPUT_LINE\n$ERROR_LINE" "$TOMCAT_SERVICE_FILE"
systemctl daemon-reload
systemctl restart fail2ban
systemctl restart guacd
systemctl restart ${TOMCAT_VERSION}
echo "Lines were added successfully to $TOMCAT_SERVICE_FILE."
fi
fi
# Done
echo
echo -e "${LGREEN}Guacamole security policy applied, but NOT YET ENABLED FOR LOCAL NETWORK(S) ${GREY}\n- Local network(s) ${SED_NETADDR}are currently whitelisted from all IP bans.\n- To alter this whitelist, edit /etc/fail2ban/jail.local then sudo systemctl restart fail2ban"
############## Start Fail2ban NGINX security policy option ###############
#if [[ "${FAIL2BAN_NGINX}" = true ]]; then
# echo -e "${LGREEN}Nginx Fail2ban policy not implemented yet.${GREY}"
# echo
#fi
############### Start Fail2ban SSH security policy option ################
#if [[ "${FAIL2BAN_SSH}" = true ]]; then
# echo -e "${LGREEN}SSH Fail2ban policy not implemented yet..${GREY}"
# echo
#fi
#Done
echo -e ${NC}