Friday, July 27, 2007

web bug (a.k.a. tracking image, clear gif, 1-by-1 gif, invisible gif)

What exactly is a Web Bug?

A Web Bug is a graphics on a Web page or in an Email message that is designed to monitor who is reading the Web page or Email message. Web Bugs are often invisible because they are typically only 1-by-1 pixel in size. They are represented as HTML IMG tags.

What information is sent to a server when a Web Bug is viewed?

  • The IP address of the computer that fetched the Web Bug
  • The URL of the page that the Web Bug is located on
  • The URL of the Web Bug image
  • The time the Web Bug was viewed
  • The type of browser that fetched the Web Bug image
  • A previously set cookie value

What kinds of uses does a Web Bug have in an Email message?

  • A Web Bug can be used to find out if a particular Email message has been read by someone and if so, when the message was read.
  • A Web Bug can provide the IP address of the recipient if the recipient is attempt to remain anonymous.
  • Within an organization, A Web Bug can give an idea how often a message is being forwarded and read.

Firefoxban a noscript extension az 1.1.6.11-es verziotol letilthatova teszi (about:config > noscript.blockNSWB)