While behavior on the web is monitored by a variety of tracking tools, in recent years, user privacy protection has become a priority, and browsers such as Firefox have also included tracking protection by default. However, it has been reported that a new tracking method has been discovered that runs out of existing tracking protection functions.
Cookies are a common way to track user behavior. Cookies include first-party cookies issued by websites you actually visit and third-party cookies issued by other domains. Third-party tracking spans multiple websites, and information such as user browsing history is used for targeted ads and more. In recent years, there has been a growing trend that tracking by such third parties violates user privacy. For example, Apple announced a new anti-tracking policy in 2019, pointing out to TNW, an overseas media outlet, that “online tracking will be treated like a security vulnerability.”
However, GitHub user aeris reported in November 2019 that “existing tracking prevention tools have discovered a tracking technique that cannot be avoided.” The tracker in question was discovered on the website of the French daily Liberation, which announced in October 2019 that it would “eliminate all ad trackers for subscribers and protect personal privacy.” The technique discovered on The Liberation’s website is to embed a first-party tracker in a website using a subdomain that redirects to a third party.
The subdomains used are almost random, and unless you block the Liberation website itself, it may be difficult to prevent tracking in this way. The Liberation website used this technique to enable user tracking by a company called Eulerian, which performs data-driven analysis. In response to this issue, Liberation claims that it was “not tracking subscribers for targeted advertising, it was just collecting data for website analysis.”
At the time of the creation of the by PhotoMIX-Company article, the difficult-to-block tracking technique discovered this time seems not to be so widely used. Still, TechCrunch points out that this can be a good alternative for websites looking for tracking alternatives to existing third-party cookies. Lukasz Olejnik, a privacy researcher at the University of Oxford, said: “If this setting contains unpredictable strings in some domain names, We can effectively avoid tools that prevent third-party tracking.”
According to Olejnik, a technique to circumvent similar anti-tracking tools had already been developed as of 2014. Nevertheless, the motivation to introduce this method has not spread much until now due to weak motives, but in recent years there has been a growing trend to protect user privacy. Olejnik believes there is a high possibility that the number of websites to be introduced will increase. On how to disable the same tracking techniques as those discovered, Olejnik suggested that a custom check mode be installed with a tracking prevention tool that detects the specific tracking techniques used by websites.