A Free Educational Resource Created by Carnegie Mellon University to Empower You to Secure Your Part of Cyberspace

Cookie

Information, usually in a file, about someone’s Internet activities, such as the date of the last visit to a Web site, preferences, etc.

A cookie is any type of information that a Web site writes to your hard disk, normally in the form of a file or an entry in a file. A Web site with cookies enabled will send your computer a cookie the first time you visit. This cookie can record such information as the current date and time or the IP address you are connecting from. The next time you visit from the same computer, this Web site will read the information from the cookie to customize your visit.

Cookies are typically used to customize pages for you based on your browser type or other information you may have provided the Web site. They are also used to rotate the banner advertisements, so it doesn't keep presenting the same one.

By default, your browser won’t send cookies from one Web site to another. With this default setting, a Web site can only keep track of your activities on one site, and not your general Web activities. However, a Web site can have services from or references to (for example, images) other Web sites that also use cookies. When this happens in a Web site, it is said to have “foreign cookies” or “third-party cookies.” Foreign cookies affect your privacy because they share your information file from the Web site you willingly visited with a Web site you may not know.

Protective Measures

Settings

You can adjust your browser settings to ensure higher levels of privacy.

In Internet Explorer, on the Tools menu, select Internet Options. On the Privacy tab, move the slider to “Medium” or an upper level of privacy.

In Netscape, disable third-party cookies by doing the following:

  • Open the Edit menu and choose Preferences.
  • Under the Privacy & Security category, choose Cookies. (If no subcategories are visible, double-click the category to expand the list.)
  • Enable cookies for the originating Web site only.

References

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