Block that script!

Block that script!

It used to be so simple to understand how a web browser and a web server communicated. The server held a bunch of pages of HTML and sent them to the browser when a user would type in a URL and navigate to that location. The HTML that was sent back to the browser was pretty much human-readable, which meant anyone with little programming knowledge and a basic knowledge of command syntax could figure out what is going on in the page.

I can say this because I remember learning HTML code in those early days in a few days’ time. While I am not a programmer, I have written code in the distant past.

Those days (both me doing any code or parsing web pages) are so over now. Today’s web servers do a lot more than just transmit a bunch of HTML. They consolidate a great deal of information from a variety of sources: banners from ad networks, images from image headers that are used in visitor analytics, tracking cookies for eCommerce sites (so they can figure out if you have been there before), content distribution network codes and many more situations.

Quite frankly, if you look at all the work that a modern web server has to do, it is a wonder that any web page ends up looking as good as it does. But this note isn’t just about carping on this complexity. Instead, it is because of this complexity that the bad guys have been exploiting it for their own evil ways for many years, using what are called script injection techniques.

Basically what is happening is because of poorly written code on third-party websites or because of clever hacking techniques, you can inject malware into a web page that can do just about anything, including gathering usernames and passwords without the browser’s knowledge.

One type of injection, SQL injection, is usually near the top of the list of most frequent attacks year after year. This is because it is easy to do, it is easy to find targets, and it gets big results fast. It is also easy to fix if you can convince your database and web developers to work together.

But there is another type of injection that is more insidious. Imagine what might happen if an ad network server would be compromised so that it could target a small collection of users and insert a keylogger to capture their IDs and passwords. This could easily become a major data breach.

A variety of security tools have been invented to try to stop these injections from happening, including secure browsers (such as, using various sandboxing techniques (such as Checkpoint’s Sandblast), running automated code reviews (such as with runtime application self-protection techniques from Vasco and Veracode), or by installing a browser extension that can block specific page content. None of these is really satisfactory or a complete solution.

If you are concerned about these kinds of injections, you might want to experiment with a couple of  browser extensions. These are not new. Many of these tools were created years ago to stop pop-up ads from appearing on your screen. They have gotten new attention recently because many ad networks want to get around the ad blockers (so they can continue to make money selling ads). But you can use these tools to augment your browser security too. If you are interested in trying one of them out, here is a good test of a variety of ad blocker performance done several years ago. There is another comparative review by LifeHacker which is also several years old that focuses on privacy features.

I was interested so I have been running two of these extensions lately: Privacy Badger (shown here) and Ghostery. I wanted to see what kind of information they pick up and exactly how many third-parties are part of my web transactions when I do my banking, buy stuff online, and connect to the various websites that I use to run my life. The number will surprise you. Some sites have dozens of third-party sites contributing to their pages.

Privacy Badger is from the Electronic Frontier Foundation, and is focused on the consumer who is concerned about his or her online privacy. When you call it up onscreen, it will show you a list of the third-party sites and has a simple three-position slider bar next to each one: you can block the originating domain entirely, just block its cookies, or allow it access. Ghostery works a bit differently, and ironically (or unfortunately) wants you to register before it provides more detailed information about third party sites. It provides a short description of the ad network or tracking site that it has discovered from reading the page you are currently browsing. The two tools cite different sites in their reports.

There are some small signs of hope on the horizon. An Israeli startup called Source Defense is in beta; they will secure your website from malicious third-party script injections such as keylogger insertions. I saw a short demo of it and it seems promising. Browsers are getting better, with more control over pop-ups and third-party cookies and blocking more obvious malware attacks. Although as browser security controls become more thorough, they also become more difficult to use. It is the nature of the Internet that security will always chase complexity.

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