A list of services and companies that perform ``CNAME cloaking'' to avoid the tracking block function of the browser is being released

As the use of cookies on websites and advertisement distribution is restricted due to privacy concerns, the number of cases of using methods to track users without using cookies is increasing. AdGuard, which develops ad blockers, has announced a list of companies and services that perform `` CNAME cloaking '', which is one of such methods and is difficult to detect and block.

AdGuard names 6,000+ web trackers that use CNAME chicanery: Feel free to feed them into your browser's filter • The Register
https://www.theregister.com/2021/03/04/adguard_cname_tracker/

Ad-Blocker Company Releases List of 6K Trackers Abusing CNAME Cloaking |
https://therecord.media/ad-blocker-company-releases-list-of-6k-trackers-abusing-cname-cloaking/

Restrictions on the use of cookies by companies are progressing, for example, Apple has completely blocked third-party cookies in Safari since March 2020 to improve privacy. However, advertisers have devised new tracking methods using CNAME records to circumvent this block.

CNAME is a mechanism to assign a nickname to a DNS server, and in this tracking method called ' CNAME cloaking ', by giving a nickname using the client site's domain to the advertiser's domain, third-party cookies are treated as if they were the first party. It is possible to make it behave like a cookie.

AdGuard published on Github a list of companies and services that perform such CNAME-based tracking.

GitHub - AdguardTeam/cname-trackers: This repository contains a list of popular CNAME trackers
https://github.com/AdguardTeam/cname-trackers

When arranging from the most frequently used, it will be as follows.

・Pardot
・Adobe Experience Cloud
・Act-On Software
・Oracle Eloqua
・Eulerian
・Webtrekk
・Ingenious Technologies
・Trace Dock
・Live Intent
・AT Internet
・Criteo
・Keyade
・Wizaly

In February 2021, a privacy researcher published a paper stating , ``CNAME trackers have increased by 21% in the past 22 months, and about 10% of the top 10,000 sites have found CNAME trackers.'' Researchers also say that 95% of websites that use CNAME trackers in this way handle personal information.

In response to CNAME cloaking, Firefox and the privacy-focused browser Brave have announced new features to detect CNAME cloaking, which is said to be difficult to detect. Similar features have also been implemented in uBlock Origin and AdGuard DNS . .

AdGuard states that it will continue to update the list announced on Github.