HackTheBox Sense - with Metasploit

Ari Kalfus | Aug 14, 2020 min read

This series will follow my exercises in HackTheBox. All published writeups are for retired HTB machines. Whether or not I use Metasploit to pwn the server will be indicated in the title.


Difficulty: Easy

Machine IP:

I kick things off with a port scan.

sudo nmap -sS -T4 -p-

Starting Nmap 7.80 ( https://nmap.org ) at 2020-06-07 16:34 EDT
Nmap scan report for
Host is up (0.015s latency).
Not shown: 65533 filtered ports
80/tcp  open  http
443/tcp open  https
sudo nmap -sT -T4 -A -sC -sV -p 80,443

Starting Nmap 7.80 ( https://nmap.org ) at 2020-06-07 16:36 EDT
Nmap scan report for
Host is up (0.014s latency).

80/tcp  open  http       lighttpd 1.4.35
|_http-server-header: lighttpd/1.4.35
|_http-title: Did not follow redirect to
|_https-redirect: ERROR: Script execution failed (use -d to debug)
443/tcp open  ssl/https?
|_ssl-date: TLS randomness does not represent time
Warning: OSScan results may be unreliable because we could not find at least 1 open and 1 closed port
Device type: specialized|general purpose
Running (JUST GUESSING): Comau embedded (92%), FreeBSD 8.X (85%), OpenBSD 4.X (85%)
OS CPE: cpe:/o:freebsd:freebsd:8.1 cpe:/o:openbsd:openbsd:4.0
Aggressive OS guesses: Comau C4G robot control unit (92%), FreeBSD 8.1 (85%), OpenBSD 4.0 (85%)
No exact OS matches for host (test conditions non-ideal).
Network Distance: 2 hops

TRACEROUTE (using proto 1/icmp)
1   13.80 ms
2   13.93 ms

It looks like 80/443 are the only ports open, and I’m looking at a lighttpd server version 1.4.35.

Browsing to brings up a login page for pfSense. A gobuster scan finds a /system-users.txt file.

gobuster dir -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt -t 30 -u -k -x txt

From https://docs.netgate.com/pfsense/en/latest/usermanager/pfsense-default-username-and-password.html, I see that the default credentials for pfSense are admin / pfsense. These do not work on the index.php page, however.

pfsense default creds

The page reveals the existence of a Rohit user with a default password.

rohit ticket

That would be Rohit / pfsense, then. These credentials allow me to login to the pfSense portal.

In Metasploit, I see there is a exploit/unix/http/pfsense_graph_injection_exec module, which is a remote code execution exploit requiring an authenticated session. Well, now that I have pfSense credentials, this should do the trick. Sure enough, this exploit gives me a root shell.

root shell

I can now collect the user and root flags.

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