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Reconnaissance:

NMAP: 

┌──(kali💀kali)-[~]
└─$ sudo nmap -sC -sV -O 10.10.10.60

80/tcp  open  http     lighttpd 1.4.35
|_http-title: Did not follow redirect to https://10.10.10.60/
|_http-server-header: lighttpd/1.4.35

443/tcp open  ssl/http lighttpd 1.4.35
|_http-title: Login
| ssl-cert: Subject: commonName=Common Name (eg, YOUR name)/organizationName=CompanyName/stateOrProvinceName=Somewhere/countryName=US
| Not valid before: 2017-10-14T19:21:35
|_Not valid after:  2023-04-06T19:21:35
|_ssl-date: TLS randomness does not represent time
|_http-server-header: lighttpd/1.4.35
┌──(kali💀kali)-[~]
└─$ sudo nmap -sU -O 10.10.10.60

All 1000 scanned ports on 10.10.10.60 (10.10.10.60) are in ignored states.

I hadn’t figure out my go-to syntax for nmap back then (first -p- --min-rate 10000, then -p [ports] -sCV).

The web server is lighttpd. The certificate on TLS isn’t filled in with any information. I can look at it in Firefox and confirm it is just defaults:

Port 80 redirects to port 443 so we really only have one port to enumerate. https://10.10.10.60/arrow-up-right

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Enumeration: HTTPS - TCP 443

Let’s start enumerating port 443. Visit the application using the browser.

We get a pfSense login page. pfSense is a free and open-source firewall and router. Since it is an off the shelf software, the first thing I did is google “pfsense default credentials” and found the following page.

I tried admin/pfsense but that did not work. I also tried common credentials such as admin/admin, pfsense/pfsense, admin/password, etc.

When that didn’t work I had a not-so-bright-idea of brute forcing the credentials using Hydra.

That ended up getting me blocked. In hindsight it makes sense. It wasn’t very smart to brute force the credentials of a firewall.

Directory Brute Force:

I didn’t get anything useful.

Let’s change our gobuster command to include extensions.

I added the extensions txt & conf to look for any configuration files or text files left by system administrators. Two files that immediately catch my eye are changelog.txt & system-users.txt.

https://10.10.10.60/system-users.txt arrow-up-rightSecurity Changelog Issue There was a failure in updating the firewall. Manual patching is therefore required Mitigated 2 of 3 vulnerabilities have been patched Timeline The remaining patches will be installed during the next maintenance window

https://10.10.10.60/system-users.txt arrow-up-rightSupport ticket Please create the following user username: Rohit password: company defaults

The change-log.txt file tells us that they’re definitely using a vulnerable version of pfSense. However, they did patch two of the three vulnerabilities that are associated with this software. We have to keep that in mind when exploiting the application. The system-users.txt file gives us credentials!

The username is rohit and the password is the default password pfsense. Let’s log into the application.

Next, run searchsploit to view if the software is associated with any vulnerabilities.

The version number is 2.1.3. If we go back to our searchsploit results, one exploit does stand out.

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Shell as root

Transfer the exploit to our directory.

Look at the exploit to see what it’s doing.

LogopfSense < 2.1.4 - 'status_rrd_graph_img.php' Command InjectionExploit Databasechevron-right

It seems that the status_rrd_graph_img.php script is vulnerable to a command injection. To exploit that, the script is passing a simple python reverse shell (with the configuration parameters we pass as arguments) as a command. It does octal encode the reverse shell command which leads me to believe that there is either some form of filtering being done at the backend or the application crashes on certain characters. To sum up, it’s a very simple script that sends a reverse shell back to our attack machine.

Therefore, let’s up a listener to receive the shell.

Then run the exploit.

For this machine, we don’t have to escalate privileges since pfSense is running as root and therefore when we exploited the command injection vulnerability we got a shell with root privileges.

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Shell with Metasploit

searchsploit shows some exploits for the HTTP server, lighttpd, but all for older versions:

On originally solving, I searched for PFSence exploits in Metasploit, and there were a couple:

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