This repo contains software I've written for the 2021 CrikeyCon Red vs Blue CTF. The 2 projects are the nginx toolkit and a beacon project for scoring points.

Because I wasn't certain there would be reliable or fast internet I wanted a way to load applications onto the server such as tools for patching software, antivirus and common tools like notepad++ and 7zip.

For this project to run all you need installed is docker and docker-compose

I build and tested this code on the versions below:

Docker version 20.10.2
docker-compose version 1.27.4

Run the server with a docker-compose up --build. This will launch the site on port 80.

To stop other teams, and potentially other teammates from accessing this tool I added basic auth to nginx. It reads the credentials from the nginx.htpasswd file in the config directory. To generate new credentials run htpasswd -c config/nginx.htpasswd admin

I've stopped the tools from being commited to git with a .gitignore file but all you need to do is drag files or folders into the toolkit/content directory and reload the page in the nginx container for them to appear.

The beacons will automatically be added there when the build script is executed.

For the RvB CTF you need to breach one of the other teams severs and send a beacon to the scoreboard with a unique string over one of the designated ports. The example given for this CTF looked like this:

 Using nc to send from a Linux (or Windows) machine

echo "8a99597f-3d56-47d3-8eba-27f6128858e5" | nc 10.10.10.10 49164

Using PowerShell from a Windows machine

PS C:\> $port=49164
PS C:\> $remoteHost = "10.10.10.10"
PS C:\> $socket = new-object System.Net.Sockets.TcpClient($remoteHost, $port)
PS C:\> $stream = $socket.GetStream()
PS C:\> $writer = new-object System.IO.StreamWriter($stream)
PS C:\> $writer.WriteLine("8a99597f-3d56-47d3-8eba-27f6128858e5")
PS C:\> $writer.Flush()

If the beacon is successful you should get a "201" response.
On the scoreboard, you'll also see a small skull icon with your teams colour on it, againest the team who's server you've planted it on. Watch out for them!. 

There was also this line at the end of the document

 Aside from using nc, or PowerShell to send your beacon, if you're smart enough and can wrap a beacon in your own Linux or Windows binary. Go for it! :) 

So I wrote some Golang code to send the beacons and a couple of scripts to build the binaries for various platforms.

The code includes a list of beacon strings and a list of ports to send the beacons to. The binary will send one of the beacons to one of the ports randonly every 5 minutes.

You can change these paramaters in lines 12, 19 & 24

The beacon/build.sh and beacon/clean.sh scripts build the binaries for Windows 64 bit, Windows 32 bit, Linux 64 bit, Linux 32 bit platforms and clean them up.