1.原因：本来在家正常休息了，我们放在上海托管机房的线上服务器突然蹦了远程不了，服务启动不了，然后让上海机房重启了一次，还是直接挂了，一直到我远程上才行。
2.现象：远程服务器发现出现这类信息
Hi, please view: 
http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
Hi, please view: http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
Hi, please view: http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
Hi, please view: http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
Hi, please view: http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
Hi, please view: http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
登录信息
然后FQ去了国外网站查看
Greetings,
Your server has been hacked and your files have been deleted.
Before they were deleted, we backed them up to a server we control.
You must send a total of 3 BTC to the address: 1B1oU6EdREYffif3**********
Failure to do so will result in your files being deleted after 5 days.
We may also leak your files.
You can e-mail onewayout@sigaint.org for support. We will not give any files before a payment has been made.
Goodbye!
发现被黑。
3.开始排查：
首先检查日志，以前做过安全运维，所以写过类似于检查命令和工具，开始一一排查。
#查看是否为管理员增加或者修改
find / -type f -perm 4000
#显示文件中查看是否存在系统以外的文件
rpm -Vf /bin/ls
rpm -Vf /usr/sbin/sshd
rpm -Vf /sbin/ifconfig
rpm -Vf /usr/sbin/lsof
#检查系统是否有elf文件被替换
#在web目录下运行
grep -r "getRuntime" ./
#查看是否有木马
find . -type f -name "*.jsp" | xargs grep -i "getRuntime"
#运行的时候被连接或者被任何程序调用
find . -type f -name "*.jsp" | xargs grep -i "getHostAddress"
#返回ip地址字符串
find . -type f -name "*.jsp" | xargs grep -i "wscript.shell"
#创建WshShell对象可以运行程序、操作注册表、创建快捷方式、访问系统文件夹、管理环境变量
find . -type f -name "*.jsp" | xargs grep -i "gethostbyname"
#gethostbyname()返回对应于给定主机名的包含主机名字和地址信息的hostent结构指针
find . -type f -name "*.jsp" | xargs grep -i "bash"
#调用系统命令提权
find . -type f -name "*.jsp" | xargs grep -i "jspspy"
#Jsp木马默认名字
find . -type f -name "*.jsp" | xargs grep -i "getParameter"
fgrep - R "admin_index.jsp" 20120702.log > log.txt
#检查是否有非授权访问管理日志
#要进中间件所在日志目录运行命令
fgrep - R "and1=1"*.log>log.txt
fgrep - R "select "*.log>log.txt
fgrep - R "union "*.log>log.txt
fgrep - R "../../"*.log >log.txt
fgrep - R "Runtime"*.log >log.txt
fgrep - R "passwd"*.log >log.txt
#查看是否出现对应的记录
fgrep - R "uname -a"*.log>log.txt
fgrep - R "id"*.log>log.txt
fgrep - R "ifconifg"*.log>log.txt
fgrep - R "ls -l"*.log>log.txt
#查看是否有shell攻击
#以root权限执行
cat /var/log/secure
#查看是否存在非授权的管理信息
tail -n 10 /var/log/secure
last cat /var/log/wtmp
cat /var/log/sulog
#查看是否有非授权的su命令
cat /var/log/cron
#查看计划任务是否正常
tail -n 100 ~./bash_history | more
查看临时目录是否存在攻击者入侵时留下的残余文件
ls -la /tmp
ls -la /var/tmp
#如果存在.c .py .sh为后缀的文件或者2进制elf文件。
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检查出有点类似于黑客的ip，只能猜测然后查看ip地址过滤出这个ip的访问信息并查看ip地址是那边的 |
Apr 17 03:14:56 localhost sshd[11499]: warning: /etc/hosts.deny, line 14: missing ":" separator
Apr 17 03:15:01 localhost sshd[11499]: Address 46.214.146.198 maps to 46-214-146-198.next-gen.ro, but this does not map back to the address - POSSIBLE BREAK-IN ATTEMPT!
Apr 17 03:15:01 localhost sshd[11499]: Invalid user ubnt from 46.214.146.198
Apr 17 03:15:01 localhost sshd[11500]: input_userauth_request: invalid user ubnt
Apr 17 03:15:01 localhost sshd[11499]: pam_unix(sshd:auth): check pass; user unknown
Apr 17 03:15:01 localhost sshd[11499]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=46.214.146.198
Apr 17 03:15:01 localhost sshd[11499]: pam_succeed_if(sshd:auth): error retrieving information about user ubnt
Apr 17 03:15:03 localhost sshd[11499]: Failed password for invalid user ubnt from 46.214.146.198 port 34989 ssh2
Apr 17 03:15:03 localhost sshd[11500]: Connection closed by 46.214.146.198
就是他了，查看历史记录
日志发现 Invalid user ubnt from 46.214.146.198
历史记录和相关访问日志已经被删除，痕迹清除。
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安装chrootkit检查是否有rootkitmkdir chrootkit
cd chrootkit/
wget ftp://ftp.pangeia.com.br/pub/seg/pac/chkrootkit.tar.gz
tar zxvf chkrootkit.tar.gz
cd chkrootkit-0.50/
lsyum install -y glibc-static
make sense
./chkrootkit
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发现检查没有异常
打开 vi /etc/motd 发现
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[root@mall ~]# vi /etc/motd
Hi, please view: http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
Hi, please view: http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
Hi, please view: http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
Hi, please view: http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
Hi, please view: http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
Hi, please view: http://pastie.org/pastes/10800563/text?key=hzzm4hk4ihwx1jfxzfizzq for further information in regards to your files!
|
查找不出后门也找不到相关命令，感觉思路受损，晕头转向。
最后查找下单天的web访问日志和相关ip访问
发现一条命令让我好奇，GET /cgi-bin/center.cgi?id=20 HTTP/1.1
并且有点异常
发现像目前最流行的bash shell 漏洞，测试一下，果然存在漏洞。
env x='() { :;}; echo vulnerable' bash -c "echo this is a test"
[root@mall ~]# env x='() { :;}; echo vulnerable' bash -c "echo this is a test"
vulnerable
this is a test
4.修复升级命令：
yum -y install yum-downloadonly
yum -y install bash-4.1.2-33.el6_7.1.x86_64.rpm
[root@mall tmp]# yum -y install bash-4.1.2-33.el6_7.1.x86_64.rpm
已加载插件：fastestmirror, security
设置安装进程
诊断 bash-4.1.2-33.el6_7.1.x86_64.rpm: bash-4.1.2-33.el6_7.1.x86_64
bash-4.1.2-33.el6_7.1.x86_64.rpm 将作为 bash-4.1.2-15.el6_4.x86_64 的更新
Loading mirror speeds from cached hostfile
* base: ftp.sjtu.edu.cn
* extras: mirrors.skyshe.cn
* updates: ftp.sjtu.edu.cn
解决依赖关系
--> 执行事务检查
---> Package bash.x86_64 0:4.1.2-15.el6_4 will be 升级
---> Package bash.x86_64 0:4.1.2-33.el6_7.1 will be an update
--> 完成依赖关系计算
依赖关系解决
======================================================================================================================================================================================
总文件大小：3.0 M
下载软件包：
运行 rpm_check_debug
执行事务测试
事务测试成功
执行事务
正在升级 : bash-4.1.2-33.el6_7.1.x86_64
清理 : bash-4.1.2-15.el6_4.x86_64
Verifying : bash-4.1.2-33.el6_7.1.x86_64
Verifying : bash-4.1.2-15.el6_4.x86_64
更新完毕:
bash.x86_64 0:4.1.2-33.el6_7.1
完毕！
重新测试
[root@mall tmp]# env x='() { :;}; echo vulnerable' bash -c "echo this is a test"
this is a test
5.完成后做了如下措施：
1.修改了系统账号密码。
2.修改了sshd端口为2220。
3.修改nginx用户nologin。
4.发现系统服务器存在bash严重漏洞 破壳漏洞(Shellshock)并修复。
5.更新完成后后面没有发现被入侵或者服务器自动宕机现象。
6.漏洞被利用过程：
我发送GET请求–>目标服务器cgi路径
目标服务器解析这个get请求，碰到UserAgent后面的参数，Bash解释器就执行了后面的命令
7.Shellshock介绍
Shellshock，又称Bashdoor，是在Unix中广泛使用的Bash shell中的一个安全漏洞，首次于2014年9月24日公开。许多互联网守护进程，如网页服务器，使用bash来处理某些命令，从而允许攻击者在易受攻击的Bash版本上执行任意代码。这可使攻击者在未授权的情况下访问计算机系统。
8.相关文章：
http://zone.wooyun.org/content/15392
http://www.freebuf.com/articles/system/50707.html
http://bobao.360.cn/news/detail/408.html
http://hacker-falcon.blog.163.com/blog/static/23979900320148294531576/
本文出自 “浩子的▁运维笔录ヽ” 博客，http://chenhao6.blog.51cto.com/6228054/1768695