The act of checking browser histories without permission is called history sniffing. Sites that have been caught history sniffing include Gamesfreak.com, TwinCities.com, Newsmax.com and YouPorn.com.
Of the 485 websites found to be participating in web sniffing, an alarming 46 of these are actually downloading browser histories. The research also showed that 17 websites were copying histories to their network. Researchers were unable to discover whether or how the histories were being utilized.
According to the study 18 of the sites are analyzing the last 220 sites their viewers have looked at. Sites found guilty include PetitChef.com, FullTono.com and Gamestorrents.com. Other sites such as YouPorn are checking their users last 21 visited sites. The sites harvest this information with the possible goal of creating a browser profile of their users.
History sniffing has been a problem for a long time, but the report defines how prevalent it is. The report even revealed that companies that provided web analytic services (like Tealium and Beencounter) actually offer history sniffing as a service.
The problem is being combated by up-to-date internet browsers. Apple Safari, Firefox and Google Chrome are able to block history sniffing. Using browsers in private browsing mode can also prevent sniffing. Firefox offers an add-on called ‘NoScript’ which prevents the flaw allowing websites to access browser histories. Firefox users can also modify their CSS code to ensure maximum protection.
With the UCLA report bringing to light how prolific history sniffing is it is likely that the other web browsers will include similar add-ons in their upcoming upgrades to make their browsers as safe as Firefox.