#!/bin/sh
#
# DropBrute.sh @20130516
#
# minimalist OpenWRT/dropbear ssh brute force attack banning script
#
# Installation steps:
#
# 1) Optionally edit the variables in the header of this script to customise
# for your environment
#
# 2) Insert a reference for this rule in your firewall script before you
# accept ssh, something like:
#
# iptables -N DropBrute
# iptables -I input_rule -i br-wan -p tcp --dport 22 -j DropBrute
# iptables -I input_rule -i br-wan -p tcp --dport 22 -m state --state NEW -m limit --limit 6/min --limit-burst 6 -j ACCEPT
#
# 3) Run the script periodically out of cron:
#
# echo '*/10 * * * * /usr/sbin/DropBrute.sh 2>&1 >> /tmp/DropBrute.log' >> /etc/crontabs/root
#
# 4) If cron is not enabled, you'll also need to run the following:
#
# /etc/init.d/cron enable && /etc/init.d/cron start
#
#
# To whitelist hosts or networks, simply add a manual entry to the lease
# file with a leasetime of -1. This can be done with the following syntax:
#
# echo -1 192.168.1.0/24 >> /tmp/DropBrute.leases
#
# A static, or non-expiring blacklist of a host or network can also be
# added, just use a lease time of 0. This can be done with the following syntax:
#
# echo 0 1.2.3.0/24 >> /tmp/DropBrute.leases
# How many bad attempts before banning. Only the log entries from the
# current day are checked.
allowedAttempts=5
# How long IPs are banned for after the current day ends.
# default is 1 days
secondsToBan=$((1*60*60*24))
# the "lease" file - defaults to /tmp which does not persist across reboots
leaseFile=/tmp/DropBrute.leases
# This is the iptables chain that drop commands will go into.
# you will need to put a reference in your firewall rules for this
#iptChain=DropBrute
iptChain=input_wan_rule
# the IP Tables drop rule
iptDropRule='-j DROP'
# the IP Tables whitelist rule
iptWhiteRule='-j RETURN'
# You can put default leasefile entries in the following space.
# Syntax is simply "leasetime _space_ IP_or_network". A leasetime of -1 is a
# whitelist entry, and a leastime of 0 is a permanent blacklist entry.
[ -f $leaseFile ] || cat <<__EOF__>>$leaseFile
-1 2400:1234:123:1000::/56
__EOF__
# End of user customizable variables (unless you know better )
ipt='/usr/sbin/ip6tables'
[ `date +'%s'` -lt 1320000000 ] && echo System date not set, aborting. && exit -1
$ipt -N $iptChain >&/dev/null
today=`date +'%d/%b/%Y'`
now=`date +'%s'`
nowPlus=$((now + secondsToBan))
echo Running DropBrute on `date` ($now)
# find new badIPs
for badIP in `cat /tmp/nginx/access.log | grep " 404 " | egrep ".*$today" | awk '{print $1}' | sort -u` ; do
found=`cat /tmp/nginx/access.log | grep " 404 " | egrep ".*[$today" | awk '{print $1}' | fgrep $badIP | wc -l`
if [ $found -gt $allowedAttempts ] ; then
if [ `egrep $badIP$ $leaseFile|wc -l` -gt 0 ] ; then
[ `egrep $badIP$ $leaseFile|cut -f1 -d ` -gt 0 ] && sed -i 's/^.* '$badIP$/$nowPlus $badIP/ $leaseFile
else
echo $nowPlus $badIP >> $leaseFile
fi
fi
done
# now parse the leaseFile
while read lease ; do
leaseTime=`echo $lease|cut -f1 -d `
leaseIP=`echo $lease|cut -f2 -d `
if [ $leaseTime -lt 0 ] ; then
if [ `$ipt -S $leaseChain|egrep $leaseIP/32 | $leaseIP |fgrep -- "$iptWhiteRule"| wc -l` -lt 1 ] ; then
echo Adding new whitelist rule for $leaseIP
$ipt -I $iptChain -s $leaseIP $iptWhiteRule
fi
elif [ $leaseTime -ge 1 -a $now -gt $leaseTime ] ; then
echo Expiring lease for $leaseIP
$ipt -D $iptChain -s $leaseIP $iptDropRule
sed -i /$leaseIP/d $leaseFile
elif [ $leaseTime -ge 0 -a `$ipt -S $leaseChain|egrep $leaseIP/32 | $leaseIP |wc -l` -lt 1 ] ; then
echo Adding new rule for $leaseIP
$ipt -A $iptChain -s $leaseIP $iptDropRule
fi
done < $leaseFile
#!/bin/sh
#
# DropBrute.sh @20130516
#
# minimalist OpenWRT/dropbear ssh brute force attack banning script
#
# Installation steps:
#
# 1) Optionally edit the variables in the header of this script to customise
# for your environment
#
# 2) Insert a reference for this rule in your firewall script before you
# accept ssh, something like:
#
# iptables -N DropBrute
# iptables -I input_rule -i br-wan -p tcp --dport 22 -j DropBrute
# iptables -I input_rule -i br-wan -p tcp --dport 22 -m state --state NEW -m limit --limit 6/min --limit-burst 6 -j ACCEPT
#
# 3) Run the script periodically out of cron:
#
# echo '*/10 * * * * /usr/sbin/DropBrute.sh 2>&1 >> /tmp/DropBrute.log' >> /etc/crontabs/root
#
# 4) If cron is not enabled, you'll also need to run the following:
#
# /etc/init.d/cron enable && /etc/init.d/cron start
#
#
# To whitelist hosts or networks, simply add a manual entry to the lease
# file with a leasetime of -1. This can be done with the following syntax:
#
# echo -1 192.168.1.0/24 >> /tmp/DropBrute.leases
#
# A static, or non-expiring blacklist of a host or network can also be
# added, just use a lease time of 0. This can be done with the following syntax:
#
# echo 0 1.2.3.0/24 >> /tmp/DropBrute.leases
# How many bad attempts before banning. Only the log entries from the
# current day are checked.
allowedAttempts=5
# How long IPs are banned for after the current day ends.
# default is 1 days
secondsToBan=$((1*60*60*24))
# the "lease" file - defaults to /tmp which does not persist across reboots
leaseFile=/tmp/DropBrute.leases
# This is the iptables chain that drop commands will go into.
# you will need to put a reference in your firewall rules for this
#iptChain=DropBrute
iptChain=input_wan_rule
# the IP Tables drop rule
iptDropRule='-j DROP'
# the IP Tables whitelist rule
iptWhiteRule='-j RETURN'
# You can put default leasefile entries in the following space.
# Syntax is simply "leasetime _space_ IP_or_network". A leasetime of -1 is a
# whitelist entry, and a leastime of 0 is a permanent blacklist entry.
[ -f $leaseFile ] || cat <<__EOF__>>$leaseFile
-1 2408:8756:af3:f000::/56
__EOF__
# End of user customizable variables (unless you know better )
ipt='/usr/sbin/ip6tables'
[ `date +'%s'` -lt 1320000000 ] && echo System date not set, aborting. && exit -1
$ipt -N $iptChain >&/dev/null
today=`date +'%d/%b/%Y'`
now=`date +'%s'`
nowPlus=$((now + secondsToBan))
echo Running DropBrute on `date` ($now)
# find new badIPs
for badIP in `cat /tmp/nginx/access.log | grep " 404 " | egrep ".*$today" | awk '{print $1}' | sort -u` ; do
found=`cat /tmp/nginx/access.log | grep " 404 " | egrep ".*[$today" | awk '{print $1}' | fgrep $badIP | wc -l`
if [ $found -gt $allowedAttempts ] ; then
if [ `egrep $badIP$ $leaseFile|wc -l` -gt 0 ] ; then
[ `egrep $badIP$ $leaseFile|cut -f1 -d ` -gt 0 ] && sed -i 's/^.* '$badIP$/$nowPlus $badIP/ $leaseFile
else
echo $nowPlus $badIP >> $leaseFile
fi
fi
done
# now parse the leaseFile
while read lease ; do
leaseTime=`echo $lease|cut -f1 -d `
leaseIP=`echo $lease|cut -f2 -d `
if [ $leaseTime -lt 0 ] ; then
if [ `$ipt -S $leaseChain|egrep $leaseIP/32 | $leaseIP |fgrep -- "$iptWhiteRule"| wc -l` -lt 1 ] ; then
echo Adding new whitelist rule for $leaseIP
$ipt -I $iptChain -s $leaseIP $iptWhiteRule
fi
elif [ $leaseTime -ge 1 -a $now -gt $leaseTime ] ; then
echo Expiring lease for $leaseIP
$ipt -D $iptChain -s $leaseIP $iptDropRule
sed -i /$leaseIP/d $leaseFile
elif [ $leaseTime -ge 0 -a `$ipt -S $leaseChain|egrep $leaseIP/32 | $leaseIP |wc -l` -lt 1 ] ; then
echo Adding new rule for $leaseIP
$ipt -A $iptChain -s $leaseIP $iptDropRule
fi
done < $leaseFile