# 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 4
cat $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/null
RETVAL=$(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
        fi
done 

#sleep 1


while [ -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