Behind "expand if it looks convenient"
Is there an ad blocker? It is said that even if you do not enter, there are about 1 billion people in the world. There are advertisements all over the Internet, and if you "block" it, the page will become smooth. As long as you can see what you want to see, you can understand that many people use ad blocking tools. There is no doubt that the Advertising Block tool is one of the popular web browser extensions.
So, do you think that with such a popular extension, people who work with bad wisdom will let it go? In fact, it may be taken advantage of. Last month, Sergey Mostsevenko, a cyber security researcher, published a report on the ad block tool on his blog.
The general ad blocking tool will leave a trace on the site viewed by the user. This trace is not enough to determine the user's browser, but what if you collect a lot of these and put the user data in the hands of the enterprise you want? From the small data traces left everywhere, you can determine the user's browser.
In the online advertising industry, getting information from browsers to identify users and devices is called fingerprints, but fingerprints = fingerprints, users can not easily delete their fingerprints.
You can delete the Cookie. You can also clear the cache. Using private mode, you can also view the network without leaving a history. However, the browser's fingerprint collects all kinds of information, such as IP address, window size, language settings, and so on. If the page you visit contains fingerprint-hidden code, the data will be drawn from there. Mostsevenko says that by tracking what fingerprints are found on which site, you can track users' movements on the Internet.
There are many kinds of ad block tools, but it is common to scan the specific elements of the website (page) you visit and do not load it so as not to display it. Specific elements that are not loaded are, of course, advertised in this case. What to block is determined based on the filter list of each ad block tool, for example, German ads, mobile ads, pop-ups, and so on. Some ad blockers allow users to intercept or upload lists and register.
About 1 billion netizens who use ad forum tools, including the forum list, are using a little bit different tools. As a result, the ad block tool is a worthwhile place for fingerprints, but it is also a very laborious task. However, there is a way to do this troublesome job effectively. In a sense, it's a creative approach, explained in a very professional and lengthy Mostsevenko blog, if it's super simple. First, we summarize the list of ad blockers you want from web browsers and investigate which elements each interceptor intercepts. Next, we load a small HTML code (various elements that are blocked at once) into the web page to see which elements are blocked where the user is not visible and which elements can be passed. Although this is a very troublesome job, if a serious company introduces the corresponding technical capabilities, it can conduct an investigation in less than a second.
In fact, Mr. Mostsevenko tested a sample ad block tool with hidden code (test environment: 2015 MacBook Pro's Safari), and it took 3 milliseconds to check element blocks against a list of 45 ad blockers. Even if it's 400 lists, it's only 20 milliseconds. Just for a moment. During page loading in web viewing, even if the hidden code is inserted and investigated, it will not be noticed at all if it is a few milliseconds.
The filter list used by each user always changes. Using different ad block tools will change each time. Updates for developers will also change. Before that, you may change the browser the user uses, or you may adjust the browser settings, such as character size. Of course, there are also cases of changing the computer itself. If you think of it this way, it is impossible to produce a perfect fingerprint. However, you can't say anything incomplete anyway. Please take it. Data is data, and data is valuable. Currently, the data industry is worth $200 billion. The ad interceptor, which was inadvertently used for convenience, also took on $200 billion at a time.
Whether you use the ad block tool or not, you can take steps to prevent your browser from being fingerprinted. Electronic Frontier Foundation recommends disabling Javascript when not needed, using large browsers with unique measures such as Safari and Firefox, minimizing browser expansion, investing in good VPN, and not allowing Coockie.
Source:FingerprintJS