防止SSH暴力破解的腳本

轉載大俠的，學習中

#!/bin/bash
cat /var/log/secure|awk '/Failed/{print $(NF-3)}'|sort|uniq -c | awk '{print $2"="$1}' > /root/black.txt
DEFINE="20"
for i in `cat /root/black.txt`
do
              IP=`echo $i | awk -F= '{print $1}'`
         NUM=`echo $i | awk -F= '{print $2}'`
            if [ $NUM -gt $DEFINE ];then
                    grep $IP /etc/hosts.deny > /dev/null
                    if [ $? -gt 0 ];then
                       echo "sshd:$IP" >> /etc/host.deny
                    fi
            fi
done