DoubleClick systems allow up to 90% of users to be identified.

Back in December last year, documents appeared that revealed some of the features of the work of the ill-fated agency NSA. It turned out that the employees of this agency could easily track Web users using DoubleClick cookies.

Now there is a publication from the Princeton team that claims that NSA capabilities are not even needed to track users. For example, a team of Princeton specialists was able to identify up to 90% of users by monitoring the traffic of systems like Google’s DoubleClick.

However, no special access to data is required. Specialists simply monitored open network traffic.

As it turned out, such systems provide a lot of information about their users. In particular, each advertising system gives a unique user ID, but researchers were able to track the web requests of specific users by grouping data using the same browser session from system to system.

Using the same cookies on social networks, researchers were able to identify users whose requests have already been tracked. As mentioned above, this method allows you to identify about 90% of users, which is very good.

Result: for each specific pageview (pageview), you can define the user and pages that this user viewed. Security measures like the https protocol have slightly complicated user requests, but the number of cookies for advertising systems makes identifying users simple enough.

As far as you can understand, only protection using networks like Tor makes tracking a user on the network impossible.

Via theverge