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***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***
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***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***
#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***者***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。
复制内容到剪贴板
代码:
检查出有点类似于***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。
复制内容到剪贴板
代码:
安装chrootkit检查是否有rootkit
mkdir chrootkit
cd chrootkit/
wget ftp://ftp.pangeia.com.br/pub/seg/pac/chkrootkit.tar.gz
tar zxvf chkrootkit.tar.gz
cd chkrootkit-0.50/
ls
yum install -y glibc-static
make sense
./chkrootkit
发现检查没有异常
打开 vi /etc/motd 发现
复制内容到剪贴板
代码:
[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
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***或者服务器自动挂机现象。
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***者在易受***的Bash版本上执行任意代码。这可使***者在未授权的情况下访问计算机系统。
