Setting Up a Proxy to Protect Your Public IP (An Introduction to Proxies)

I recently purchased a static IP address. While this is great for setting up VPNs, websites, and other major benefits it bothered me that I normally visit CTFs and sites that contain malicious code to accomplish these CTF challenges. There had to be a way I could better protect my public IP from direct exposure in the event I did something stupid while surfing the web. This is where a proxies come into play.

A proxy is exactly the same thing meant in the English language; think if computer A who set up the proxy wants to talk to computer C. An intermediary could be introduced (Proxy Server B) so that when computer C talks to computer A it has to go through Proxy Server B. Thus Computer C thinks its talking to Proxy Server B and only sees that IP address; when in reality all traffic is getting forwarded to computer A and vise versa.


This creates a layer of abstraction. There are many types of proxies such as reverse proxies which is used mainly for public facing web sites. We are strictly using our proxy as an anonymous proxy in that it will allow us to surf the web anonymously. There are ways to compromise proxies, set them up to be used as part of a proxy chain, and other uses for them but those topics will be out of scope for today. Lets focus on setting up a proxy on AWS before deep diving into those topics.

To begin lets log into the AWS Management Console to set up our free proxy. Registering for AWS is free and simple, navigate to:

Then sign up for an account to follow along. 

Once you are logged into the AWS console, select the "Launch a virtual machine With EC2" under the "Build a solution" section. Click the Ubuntu operating system. From here you could just click the "Launch Instance" button but let's create a key pair so that we may ssh into our box as designated by (1) in the image below.
Give your key pair a relevant name and click the "Create new key pair" button. You'll be prompted with a screen; in our case we are going to use PuTTY to login but you can set up your ssh anyway as desired. Selecting RSA as the pair type and .ppk for the key file format will accomplish what's needed to ssh into the AWS Ubuntu box. Save this key pair to a safe location and do not lose it. Now the "Launch Instance" button can be clicked.

You should now be brought to the Instances console. Note your "Public IPv4 DNS" as it will be necessary to set up ssh in PuTTY. Download PuTTY for your desired OS and follow the install instructions. Once this is done, launch PuTTY and enter the following under the Session categories' "Host Name (or IP address)":
ubuntu@<Public IPv4 DNS>

The port should default to 22. Under the Connection category in PuTTY expand SSH and select Auth. Above the Open button there should be a Browse button; browse to your saved .ppk file and select it. Click the Open button and you will ssh into your ubuntu box on AWS.

Run the following commands:
sudo apt update && sudo apt upgrade
sudo apt install tinyproxy

This will install the latest tinyproxy server on your ubuntu machine. It's now time to configure your new proxy to accept your static public ip address. Note if you don't have a static public IP you will want to set up DDNS or watch for your public IP address to change and thus update the proxy server config file. Run the following command:
sudo nano /etc/tinyproxy/tinyproxy.conf

If desired you can change the default Port from 8888; scroll down to the text "Allow 127.0.0.1" and enter this line:
Allow <your public IPv4>

Hint, if you want to find your public IP in Linux you may run "curl ifconfig.co". Save and exit the nano (or preferred) editor and restart the tinyproxy daemon (service for you windows users):
sudo /etc/init.d/tinyproxy restart

Okay great, we now have a proxy. But we are not quite done yet; we need to add a firewall exception on AWS. To do that, under the "Network & Security" category click "Security Groups". Click the "Create Security Groups" button in the upper right and enter in your security group name. I'd recommend creating a security group dedicated to proxies. Add the following inbound rule to this security group:


Where Port range is whatever port that the tinyproxy daemon is listening on. Then navigate back to your instances console, right-click on your instance and select Security >> change security groups. Add the security group you created above.

Excellent! We now have a proxy. To test you can go to any browser and set the proxy setting to use the AWS Instance's "Public IPv4 address". When searching "What's my ip" in google your Proxy's public IPv4 address should show. It's that simple and now you can surf the web and have peace of mind that your Public IP is protected.


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