Most people today understand that their online privacy and Cyber Security are both under threat in a way that they never have been before. This is partly our own fault, of course – there are consequences to handing over the vast amounts of data to Facebook and Google that many of us do.
However, there is also a whole host of information about our computers, internet connections, and browsing software that we routinely reveal to websites and online services just by connecting to them.
Your IP Address
Let’s start with the most obvious piece of personal data that websites you visit are going to log – your IP address. Whenever you connect to an online server, a handshake is performed. As part of this process, your device is required to share its IP address with the server.
Of course, if you connect to a VPN or proxy server before you connect to the wider internet, the servers will see the IP address of the intermediary server, not that of the device you are using.
Preventing a website from logging your IP address is pretty easy: you only need a VPN or proxy server. As well as being able to buy access to these services, you can also set up your own VPN or proxy server relatively simply- Raspberry Pi can do it.
But while many people know how to disguise their IP address, there are other things that are regularly overlooked.
Your user agent gives websites information about the web browser that you are using, as well as information about your system and the type of device you are browsing on. This is necessary so websites can dynamically rearrange themselves to achieve the best results for the user.
Anyone who remembers mobile internet browsing before this approach became the standard will recall when websites had to produce entirely separate mobile versions of their websites – an approach that is now dying out.
Unlike the handshake that reveals your IP address, user agent strings are not uniform; there is no single standard that is used. In fact, they can vary wildly from one another. Fortunately, you can alter your own user agent string without having an in-depth knowledge of precisely how it works.
Some mobile web browsers enable you to change your user agent string on the fly in order to have websites identify your browser differently. When you switch between ‘mobile view’ and ‘desktop view’ on your mobile browser, this is what you are changing.
What Does a User Agent Reveal?
The amount of information that your web browser gives away about your system might surprise you. Recently, Mozilla made the decision to stop sending information about the user’s CPU architecture in the user agent for Firefox. The information in a user agent cannot generally be used to identify your machine directly.
However, it can be used as part of fingerprinting – a process whereby various individual pieces of data about a user are used to build a profile of them and track them without them ever handing over any personal data.
In the earliest days of the internet, websites would only be configured to work with the small number of browsers around which the vast majority of internet users had coalesced. Anyone trying to access a website using an unsupported browser would have difficulties. They would find themselves facing either incomplete data or total denial of access.
Today, things are very different. Websites now accept user agents from just about any browser. Many browsers are ultimately built upon the same engine and so can borrow the user agent of their parent browser. However, even if the user agent is identifying with a different web browser, it still contains a lot of information that is specific to your system.
For example, your user agent also includes information about the operating system of the device you are browsing on, the maximum resolution of your desktop, and the size of your browser window.
All of these have legitimate uses. Knowing all of this information enables websites to rearrange themselves to deliver an optimal user experience. However, it is important for internet users to be aware that even if they are taking measures like using VPNs and proxies to disguise their IP addresses, their user agent might still be giving away a lot of information about them.
While this information can be useful, it can also be used against you. Even if you take measures to block adverts and unauthorized scripts from running when you visit websites and disable any trackers, your efforts can still be undermined by fingerprinting.
When it comes to fingerprinting, your user agent enables you to be tracked and profiled passively. It is possible to alter your user agent, or you can look for a browser that spoofs this information by default.