# cat /var/log/secure | awk ‘/Failed/{print $(NF-3)}‘ | sort | uniq -c | awk ‘{print $2" = "$1;}‘

#!/bin/bash#Program:#       Use to monitor the user who try to login.#       防止SSH用户暴力破解脚本##Usage:#       赋予可执行权限并添加到crontab#       请先修改19行NUM对应的登录失败次数(默认100),超过此值则会添加到/etc/hosts.deny并且发送邮件#       建议使用sendEmail发送邮件(不会被当作垃圾邮件而屏蔽) http://caspian.dotconf.net/menu/Software/SendEmail/#       sendmail使用qq、163邮箱测试通过,默认的mail客户端发送qq邮箱会拒收需要添加白名单、163通过#History:#2013/10/13         Ver:1.02        By Jack##PATH=/sbin:/usr/sbin:/bin:/usr/bin:~export PATH#定义阀值，超出此值则添加到黑名单并发送邮件NUM=100#检查是否有root权限[ $UID != 0 ] && echo -e "\e[0;31mSorry,Please run as root!\e[0m" && exit 2#检查安全日志文件是否存在且可读log=/var/log/secure[ ! -e $log ] || [ ! -r $log ] && echo -e "\e[0;31mMake sure the file $log exist or can be readable!\e[0m" && exit 3#登陆失败的IP地址列表ssh_list=/root/logs/ssh_list[ ! -e ${ssh_list} ] && mkdir -p `dirname ${ssh_list}`#判断日志中是否存在ssh登录失败ip，如果没有则退出，否则添加至${ssh_list}cat $log |grep ‘Failed‘ &>/dev/null [ $? != 0 ] && exit 4cat $log|awk ‘/Failed/{print $(NF-3)}‘|uniq -c|sort -nr|awk ‘{print $2"=>"$1}‘ > ${ssh_list}#定义黑名单文件(Tcpwrappers)deny_file=/etc/hosts.deny#定义发送的黑名单邮件列表地址mail_file=/root/logs/mail_file[ ! -d `dirname ${mail_file}` ] && mkdir -p `dirname ${mail_file}`#选择邮件发送端,如果使用sendEmail，请下载后将sendEmail.pl拷贝到/usr/bin并赋予x权限if [ -e /usr/bin/sendEmail.pl ] && [ -x /usr/bin/sendEmail.pl ]then        sendmail="mailA"elif [ -e /bin/mail ] && [ -x /bin/mail ]then        sendmail="mailB"else        sendmail="None"fi#关于sendEmail设置send_user=‘xxxx@qq.com\‘ #发送者地址smtp_user=‘xxxx‘ #登陆smyp服务器的用户名smtp_pass=‘xxxx‘ #登陆smtp服务器用户的密码smtp_addr=‘smtp.qq.com:25‘ #smtp地址和端口recv_user=‘115466xxxx@qq.com jack_blues@163.com\‘ #接收者邮件地址send_mailA(){        /usr/bin/sendEmail.pl -f ${send_user} -t ${recv_user} -s ${smtp_addr} -u "SSHD WARNINGS" -m "`cat ${mail_file}`" -xu ${smtp_user} -xp ${smtp_pass} > /dev/null 2>&1}send_mailB(){        /bin/mail -s "Failed sshd Login Users" ${recv_user} < ${mail_file}}#测试网络test_network(){        #ping 8.8.8.8 -c2 &>/dev/nullRETVAL=$(curl -I -o /dev/null -s -w %{http_code} http://www.baidu.com/)}for i in `cat ${ssh_list}`do        COUNT=`echo $i|awk -F"=>" ‘{print $2}‘`        IPADDR=`echo $i|awk -F"=>" ‘{print $1}‘`        if [ ${COUNT} -ge ${NUM} ];then           grep $IPADDR ${deny_file} 2>/dev/null           while [ $? -ne 0 ]            do                echo "sshd:${IPADDR}" >> ${deny_file}                 echo "<警告>:IP为${IPADDR}的用户尝试使用SSH登陆的次数大于限定值$NUM,其尝试次数为$COUNT">>${mail_file}           done        fidone #sleep 1while [ -e ${mail_file} ] do     test_network     [ $RETVAL -ne 200 ] && exit 5     case $sendmail in            mailA)send_mailA;;            mailB)send_mailB;;            None)exit 6     esac     rm -f ${mail_file}done