How Modern Browsers Keep You Safe (Without Telling You)

On occasion, you might have seen a red warning from your internet browser when it blocks access to a potentially harmful website. Blocks like those are only one of the many, many security measures modern browsers have in place to keep you safe online.

Browsers Block Malicious Websites Before They Load

In the early days of the internet, browsers like Netscape Navigator and Internet Explorer only had minimal, if any, security features. That’s why the spread of malware and phishing scams were way more common back in the day.

Today’s browsers make the internet a much safer place than it once was. Google keeps a constantly updated database of malicious URLs by scanning every site it can access. This feature is called Google Safe Browsing.

Firefox, Brave, Chrome, Safari, and others use this database to warn you when you’re trying to access one of those blacklisted URLs. Microsoft maintains its own version of this database called Defender SmartScreen, which Microsoft Edge relies on.

The database and the scans run locally on the device, and the browsers automatically fetch and update their local lists multiple times in an hour. Before loading a URL, the browser checks it against the huge list of unsafe URLs, and only loads the website if it’s safe.

Google is constantly scanning billions of URLs for phishing sites (fake clones of real websites designed to steal your sensitive information). Machine learning algorithms look for signs of shady design and behavior in real-time and flag suspicious websites.

They Sandbox Tabs

“Sandboxing” an app lets it run in a secure environment where it can’t affect the user space or the network. If you suspect an app has malware, you could test it inside a virtual machine. An isolated virtual machine would become a sandbox where the app can’t access or infect the actual system.

Modern browsers do something similar with tabs. Every new tab you open runs in its own restricted sandbox. Each of these sandboxes is contained with strict restrictions and permissions.

That’s why you can adjust cookies and other site permissions individually for every site you visit. You have to manually grant access when a site wants to access your location or camera, for example.

Even if one tab is exposed to malware, it’s confined to that tab only. The sandboxing doesn’t let it spread across other tabs or your local files on the system.

Before browsers adopted this sandboxing architecture, all tabs and extensions ran as a single whole process. If one tab was infected, it would crash the entire browser, and even compromise your entire system.

They Automatically Patch Vulnerabilities

Internet browsers update far more often than other types of software, even though you rarely ever see the browser update itself. At most, you’ll get a prompt to restart the browser after a new update has been installed. That’s because browser updates happen in the background, every two or four weeks.

Major updates that come with new features or upgrades are rolled out every month, but in between these major updates, browsers frequently get security patches.

The reason browsers need so many security patches is that vulnerabilities in these apps are constantly popping up. For example, you can find thousands of open bug reports for Chromium (the browser that powers Brave, Chrome, Edge, and others) on Chromium’s issue tracker page. . The Mozilla Security page tracks the security fixes pushed for vulnerabilities in Firefox.

But why do browsers have so many vulnerabilities and bugs in the first place? The answer isn’t developer error (although that is the culprit sometimes); it’s because browsers are incredibly complex.

Browsers have to run code in a lot of different languages and not just render web content but provide a bunch of additional features like password managers and extensions. They’re basically tiny operating systems with millions of lines of code, including third-party APIs. Bugs and vulnerabilities are basically inevitable.

In the early days of the internet, browsers had to be updated with a physical medium, like a floppy disk or CD. The companies themselves didn’t push fixes for security vulnerabilities all that often. Modern browsers are far safer because of the automatic updates I mentioned and advanced bug bounty programs.

Your Connections Are Auto-Upgraded to HTTPS

There was a time when most of the data sent over the internet wasn’t encrypted at any point. Anyone with access to your network could “sniff” your internet data packets. They would not only know which websites you visited, but also what you were doing on the website.

While it’s now largely phased out, the Hyper Text Transfer Protocol or HTTP is how your browser and servers used to talk to each other. Your browser would send an HTTP request to get a file from a server, for example. The HTTP request was just a bunch of text specifying exactly what the browser was looking for. Then the server would respond with the content your browser requested—HTML code, image files, text or whatever.

Since neither step was encrypted, an attacker could intercept exactly what you’re requesting and what the server is sending back, including sensitive info like login credentials. They could even tamper with what the server sent back.

Hyper Text Transfer Protocol Secure or HTTPS fixed that vulnerability. The request and response between the site and the browser are now encrypted and kept private. If a URL starts with and you see a lock icon next to the loaded URL, it means the established connection is secure.

With HTTPs, no one can snoop on the data packets in transit, even if they are connected to the same network. The most they can see is which websites you’re visiting, but not the data being sent back and forth.

Even though HTTP is now being phased out and HTTPS is almost everywhere, you might end up clicking an old HTTP link at some point. Modern browsers are built to “prefer” HTTPS connections so they automatically redirect the URL to HTTPS. If the HTTPS alternative isn’t available and the browser has to fall back on HTTP, it warns you that the connection is unsafe.

LibreWolf is a modified version or “fork” of the standard Mozilla Firefox browser. This browser, and others like it, are aggressively configured to make the browser as private and as secure as possible.

For example, it disables all telemetry and data collection on the browser’s side, includes features to minimize browser fingerprinting, removes supporting Mozilla features and services that aren’t necessary for core functionality, forces HTTPS on all connections, auto-deletes cookies, and so on. Compared to the out-of-box settings and features of Firefox, LibreWolf is much more privacy-friendly.

There’s another version of Firefox called the Tor Browser which connects to the Tor network—a decentralized version of the internet where the users are functionally anonymous. The Tor browser is even more aggressive in its privacy safeguards, going as far as disabling JavaScript and locking the window size, so the servers can’t tell what your screen size is. Without JavaScript and cookies enabled, sites tend to break, but that’s not usually a problem on the Tor network, where sites with the special “.onion” domain are typically designed without JavaScript.

Credit: Tor

Google Chrome also has privacy-hardened alternatives like Cromite.

Those are only some of the ways modern browsers keep us safe online. There are even more defense systems always active in the background, and by choosing the right browser, you can make your online activity more secure than it already is.