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First-party cookie

(also HTTP cookie)

First-party cookie definition

A first-party cookie is a tiny text file that gathers user information, such as website settings and login data, that they enter while using the web. The purpose of a cookie is to store this data and provide users with easier access to it later. By tracking online user behavior, first-party cookies can create a database of users’ interests and browsing preferences, which offers a better browsing experience. However, if users decide to allow the cookie to remember the data, attackers may use that opportunity for identity theft or other malicious purposes. In addition, they can interfere with users’ data by using different methods.

See also: session hijacking, malvertising

How do hackers misuse first-party cookies?

  • Malvertising. Hackers can implement first-party cookies in malware ad campaigns that will enter users’ computers as soon as they click on the ad.
  • Cross-site scripting. First-party cookies can transmit malicious codes that hackers put in them. This way, hackers can get unauthorized access to users’ accounts and data.
  • Session hijacking. Hackers utilize first-party cookies to hijack the users’ sessions and impersonate them to access their data or even perform actions on the users’ behalf.
  • Data harvesting. Attackers can gather user data through first-party cookies, such as browsing patterns, search terms, and other private information. Then, they might offer this information for sale on the dark web or utilize it for other suspicious activities.
  • Social engineering attacks. Hackers employ manipulative strategies using first-party cookies to persuade users to disclose sensitive data like credit card details or login credentials.