{"id":108632,"date":"2023-02-07T08:00:09","date_gmt":"2023-02-07T08:00:09","guid":{"rendered":"https:\/\/kasperskycontenthub.com\/securelist\/?p=108632"},"modified":"2023-02-06T09:06:10","modified_gmt":"2023-02-06T09:06:10","slug":"web-beacons-on-websites-and-in-email","status":"publish","type":"post","link":"https:\/\/securelist.com\/web-beacons-on-websites-and-in-email\/108632\/","title":{"rendered":"Web beacons on websites and in e-mail"},"content":{"rendered":"

There is a vast number of trackers<\/a>, which gather information about users’ activities online. For all intents and purposes, we have grown accustomed to online service providers, marketing agencies, and analytical companies tracking our every mouse click, our social posts, browser and streaming services history. The collected data can be used for improving their user interfaces or the overall user experience, or to personalize ads.<\/p>\n

There exist various types of trackers meant for collecting different types of information: advertising (AdAgency) trackers, analytics (WebAnalytics) trackers, and so on. Most of these are largely used on websites and inside applications. There are more versatile trackers too, used on websites, inside applications, and even in e-mail. This article describes one of these tracker types: web beacons. We demonstrate what tracking systems’ and companies’ web beacons our security products (anti-tracking browser extensions and antispam technology) detect most often.<\/p>\n

What web beacons are<\/h2>\n

Web beacons, or web bugs, also known as tracker pixels or spy pixels, among other names, are tracking elements used on web pages, inside applications and in e-mail for checking that the user has accessed certain content (opened an e-mail or visited a web page). Their main purpose is to collect statistics and build analytical reports on the user’s activities.<\/p>\n

Web beacons on websites track visitors. Analytical marketing agencies or website owners themselves can use these to measure how well certain content or promotional campaigns performed, or how their audiences responded. Some websites use tracker pixels as watermarks for their content, for example, to track down illegal copies.<\/p>\n

The main purpose of web beacons in e-mail, just as those on websites, is to count users who interact with the content. For example, tracker pixels can be used to make a report on e-mail open rates. These help companies to find out which e-mail campaigns their users find interesting and which they do not. For example, if an e-mail campaign sees declining open rates, the company may choose to either replace the subject with something more eye-catching or clickbaity, or on the contrary, make it more matter-of-fact and informative.<\/p>\n

How web beacons work<\/h2>\n

A beacon on a web page is typically an image that loads from an external source. The size is usually one or even zero pixels, so invisible to the human eye. Hence the name: “spy pixel”. Additionally, the CSS display property can be set to “none” (do not display) to hide the image. Less common are JavaScript beacon implementations, such as Beacon API<\/a>: an interface that allows sending requests to a server without expecting a response.<\/p>\n

\"Example<\/a><\/p>\n

Example of web beacon location in the HTML code of a website<\/em><\/strong><\/p>\n

E-mail web beacons are implemented in a similar way: invisible images are placed within the e-mail body, or JavaScript code is added in an HTML attachment.<\/p>\n

\"Example<\/a><\/p>\n

Example of web beacon location in the HTML part of an e-mail<\/em><\/strong><\/p>\n

When the web page or e-mail is opened, a request is sent to the web beacon server. If the web beacon is an image the request is to upload this image. Otherwise it is a request specified in the JavaScript code, usually one that doesn’t require a response. The following information is typically communicated to the server:<\/p>\n