Commit b2df284d authored by UltimateByte's avatar UltimateByte Committed by GitHub
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parent df8efb0f
# Name: Wrong Listener Killer
# Description: Makes sure that the wrong apps don't listen to the ports you want
# Help: Default settings are to make sure that what listens to port :80 is httpd and started as root
# Developer: Robin Labadie
# Version: 2017-05-24
## Settings
portcheck=":80" # Which port to check, leaving a space afterwards might help not mistaking
allowedname="httpd" # Which process should we get on speccified port
allowedpath="/usr/sbin/httpd" # Which is the correct path to run it
allowedusers="root;" # Which is the correct user to run it (separate with ; )
logdir="/root" # Log directory (don't end with /)
maillog="root@localhost" # Mail to send an alert to if a threat is detected
## Misc vars
selfname="wlk" # Name of the script and log
log="${logdir}/${selfname}.log" # Define log name
maillogsize="10" # Define the amount of log to send by mail
## Logging
# Create logfile
if [ -n "${log}" ]&&[ ! -f "${log}" ]; then
touch "${log}"
# echo and log at the same time
echo -e "${currmessage}"
echo -e "$(date +%Y-%m-%d_%H:%M:%S) - ${selfname} - ${currmessage}" >> "${log}"
fn_logecho "[START] Initiating ${selfname}"
## Find PIDs and define variables
# Seek PID of the app listening to port
pid="$(netstat -atunp | grep "${portcheck} " | grep LISTEN | awk '{print $7}' | awk -F "/" '{print $1}')"
# If no PID is found
if [ -z "${pid}" ]; then
fn_logecho "[ERROR] Could not find a matching PID"
fn_logecho " * It is likely that nothing listens to port ${portcheck}"
exit 1
# Check name of the process listening to port 80
pidname="$(netstat -atunp | grep "${portcheck} " | grep LISTEN | awk '{print $7}' | awk -F "/" '{print $2}')"
# Find out which user owns this PID
piduser="$(ps -u -p "${pid}" | tail -1 | awk '{print $1}')"
# Find out the start command (location) of the PID
pidcommand="$(ps -u -p "${pid}" | tail -1 | awk '{print $11}')"
# If one of these vars are unset, then something went wrong
if [ -z "${pidname}" ]||[ -z "${piduser}" ]||[ -z "${pidcommand}" ]; then
fn_logecho "[ERROR] Could not find a matching PID"
fn_logecho " * It is likely that nothing listens to port ${portcheck}"
fn_logecho "Exiting"
exit 1
# Display some nice output to the user
fn_logecho "Current program listening to ${portcheck} is : PID: ${pid}\tName: ${pidname}\tUser: ${piduser}\tPath: ${pidcommand}"
## Evaluate issues
# Check if a malicious program is started
# 1) If the process name listening to port is wrong
if [ "${pidname}" != "${allowedname}" ]; then
fn_logecho "[WARNING] Program listening to ${portcheck} is ${pidname} instead of ${allowedname}"
# 2) If the process doesn't belong to an allowed user
usersamount="$(echo "${allowedusers}" | awk -F ';' '{ print NF }')"
# Recursively check if user is part of allowed users
for ((usersindex=1; usersindex <= usersamount; usersindex++)); do
# Put current user into a test variable
usertest="$(echo "${allowedusers}" | awk -F ';' -v x=${usersindex} '{ print $x }')"
# Test if user is allowed, register success if so
if [ "${piduser}" == "${usertest}" ]; then
# User not allowed
if [ "${allowedtorun}" == "0" ]; then
fn_logecho "[WARNING] ${piduser} is not allowed to run ${allowedname}"
# 3) If the process path isn't right
if [ "${pidcommand}" != "${allowedpath}" ]; then
fn_logecho "[WARNING] ${pidcommand} is not a valid path for ${allowedname}"
## Take action
if [ "${harm}" == "1" ]; then
fn_logecho "[ALERT] malicious process listening on port ${portcheck} found"
fn_logecho "[INFO] The following process will be killed: ${pid} ${pidname} ${piduser} ${pidcommand}"
kill -9 "${pid}"
fn_logecho "[OK] Job done, exiting"
tail -${maillogsize} "${log}" | mail -s "localhost - ${pidname} - ${portcheck} killed" ${maillog}
fn_logecho "[OK] This program seems legit, exiting."
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