超级NB的防DDOS(小量级)攻击的脚本
# tree /usr/local/ddos/ /usr/local/ddos/ ├── ddos.conf ├── ddos.sh ├── ignore.ip.list └── LICENSE 0 directories, 4 files
# ll /usr/local/sbin/ddos lrwxrwxrwx 1 root root 23 Sep 13 15:36 /usr/local/sbin/ddos -> /usr/local/ddos/ddos.sh # cat /etc/cron.d/ddos.cron SHELL=/bin/sh */1 * * * * root /usr/local/ddos/ddos.sh >/dev/null 2>&1
查看关键的几个脚本:
# cat ddos.conf ##### Paths of the script and other files PROGDIR="/usr/local/ddos" PROG="/usr/local/ddos/ddos.sh" IGNORE_IP_LIST="/usr/local/ddos/ignore.ip.list" CRON="/etc/cron.d/ddos.cron" APF="/etc/apf/apf" IPT="/sbin/iptables" ##### frequency in minutes for running the script ##### Caution: Every time this setting is changed, run the script with --cron ##### option so that the new frequency takes effect FREQ=1 ##### How many connections define a bad IP? Indicate that below. NO_OF_CONNECTIONS=150 ##### APF_BAN=1 (Make sure your APF version is atleast 0.96) ##### APF_BAN=0 (Uses iptables for banning ips instead of APF) #APF_BAN=1 APF_BAN=0 ##### KILL=0 (Bad IPs are'nt banned, good for interactive execution of script) ##### KILL=1 (Recommended setting) KILL=1 ##### An email is sent to the following address when an IP is banned. ##### Blank would suppress sending of mails EMAIL_TO="xxx@xxx.com" ##### Number of seconds the banned ip should remain in blacklist. BAN_PERIOD=600
# cat ddos.sh #!/bin/sh ############################################################################## # DDoS-Deflate version 0.6 Author: Zaf <zaf@vsnl.com> # ############################################################################## # This program is distributed under the "Artistic License" Agreement # # # # The LICENSE file is located in the same directory as this program. Please # # read the LICENSE file before you make copies or distribute this program # ############################################################################## load_conf() { CONF="/usr/local/ddos/ddos.conf" if [ -f "$CONF" ] && [ ! "$CONF" == "" ]; then source $CONF else head echo "\$CONF not found." exit 1 fi } head() { echo "DDoS-Deflate version 0.6" echo "Copyright (C) 2005, Zaf <zaf@vsnl.com>" echo } showhelp() { head echo 'Usage: ddos.sh [OPTIONS] [N]' echo 'N : number of tcp/udp connections (default 150)' echo 'OPTIONS:' echo '-h | --help: Show this help screen' echo '-c | --cron: Create cron job to run this script regularly (default 1 mins)' echo '-k | --kill: Block the offending ip making more than N connections' } unbanip() { UNBAN_SCRIPT=`mktemp /tmp/unban.XXXXXXXX` TMP_FILE=`mktemp /tmp/unban.XXXXXXXX` UNBAN_IP_LIST=`mktemp /tmp/unban.XXXXXXXX` echo '#!/bin/sh' > $UNBAN_SCRIPT echo "sleep $BAN_PERIOD" >> $UNBAN_SCRIPT if [ $APF_BAN -eq 1 ]; then while read line; do echo "$APF -u $line" >> $UNBAN_SCRIPT echo $line >> $UNBAN_IP_LIST done < $BANNED_IP_LIST else while read line; do echo "$IPT -D INPUT -s $line -j DROP" >> $UNBAN_SCRIPT echo $line >> $UNBAN_IP_LIST done < $BANNED_IP_LIST fi echo "grep -v --file=$UNBAN_IP_LIST $IGNORE_IP_LIST > $TMP_FILE" >> $UNBAN_SCRIPT echo "mv $TMP_FILE $IGNORE_IP_LIST" >> $UNBAN_SCRIPT echo "rm -f $UNBAN_SCRIPT" >> $UNBAN_SCRIPT echo "rm -f $UNBAN_IP_LIST" >> $UNBAN_SCRIPT echo "rm -f $TMP_FILE" >> $UNBAN_SCRIPT . $UNBAN_SCRIPT & } add_to_cron() { rm -f $CRON sleep 1 service crond restart sleep 1 echo "SHELL=/bin/sh" > $CRON if [ $FREQ -le 2 ]; then echo "0-59/$FREQ * * * * root /usr/local/ddos/ddos.sh >/dev/null 2>&1" >> $CRON else let "START_MINUTE = $RANDOM % ($FREQ - 1)" let "START_MINUTE = $START_MINUTE + 1" let "END_MINUTE = 60 - $FREQ + $START_MINUTE" echo "$START_MINUTE-$END_MINUTE/$FREQ * * * * root /usr/local/ddos/ddos.sh >/dev/null 2>&1" >> $CRON fi service crond restart } load_conf while [ $1 ]; do case $1 in '-h' | '--help' | '?' ) showhelp exit ;; '--cron' | '-c' ) add_to_cron exit ;; '--kill' | '-k' ) KILL=1 ;; *[0-9]* ) NO_OF_CONNECTIONS=$1 ;; * ) showhelp exit ;; esac shift done TMP_PREFIX='/tmp/ddos' TMP_FILE="mktemp $TMP_PREFIX.XXXXXXXX" BANNED_IP_MAIL=`$TMP_FILE` BANNED_IP_LIST=`$TMP_FILE` echo "Banned the following ip addresses on `date`" > $BANNED_IP_MAIL echo >> $BANNED_IP_MAIL BAD_IP_LIST=`$TMP_FILE` netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -nr > $BAD_IP_LIST cat $BAD_IP_LIST if [ $KILL -eq 1 ]; then IP_BAN_NOW=0 while read line; do CURR_LINE_CONN=$(echo $line | cut -d" " -f1) CURR_LINE_IP=$(echo $line | cut -d" " -f2) if [ $CURR_LINE_CONN -lt $NO_OF_CONNECTIONS ]; then break fi IGNORE_BAN=`grep -c $CURR_LINE_IP $IGNORE_IP_LIST` if [ $IGNORE_BAN -ge 1 ]; then continue fi IP_BAN_NOW=1 echo "$CURR_LINE_IP with $CURR_LINE_CONN connections" >> $BANNED_IP_MAIL echo $CURR_LINE_IP >> $BANNED_IP_LIST echo $CURR_LINE_IP >> $IGNORE_IP_LIST if [ $APF_BAN -eq 1 ]; then $APF -d $CURR_LINE_IP else $IPT -I INPUT -s $CURR_LINE_IP -j DROP fi done < $BAD_IP_LIST if [ $IP_BAN_NOW -eq 1 ]; then dt=`date` if [ $EMAIL_TO != "" ]; then cat $BANNED_IP_MAIL | mail -s "IP addresses banned on $dt" $EMAIL_TO fi unbanip fi fi rm -f $TMP_PREFIX.*
# cat ignore.ip.list 127.0.0.1 10.100.0.5 #不防御的ip
注意权限:
# ll /etc/cron.d/ddos.cron -rw-r--r-- 1 root root 71 Sep 14 17:13 /etc/cron.d/ddos.cron
注意软连接:
# ll /usr/local/sbin/ddos lrwxrwxrwx 1 root root 23 Sep 13 15:36 /usr/local/sbin/ddos -> /usr/local/ddos/ddos.sh
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