The Web Hikers guide to
Outpost Firewall

Home > FAQ > Web Bugs

Web Bugs

Bottom

What are Web Bugs?

Web Bugs are found in web pages and and html formatted e-mail in <IMG> tags. They are also invisible as they are transparent gif's that are usually 1x1 pixels in size (not all all 1x1 pixels are Web Bugs, transparent 1x1 pixel gif's are used as spacers by web designers so that they can position elements exactly where they want it on a page). Sometimes you will find Web Bugs being called Web Beacons.

How do you know if a Web Bug is really a Web Bug and not a spacer?

Web Bugs usually are downlaoded from a different site, whereas a spacer will nearly always be stored locally on the sites server.

What uses do Web Bugs have?

“Ad networks can use Web bugs to add information to a personal profile of what sites a person is visiting. The personal profile is identified by the browser cookie of an ad network. At some later time, this personal profile which is stored in a data base server belonging to the ad network, determines what banner ad one is shown.

Another use of Web bugs is to provide an independent accounting of how many people have visited a particular Web site.

Web bugs are also used to gather statistics about Web browser usage at different places on the Internet.” - The Privacy Foundation

What do they Web Bugs do?

When viewed a web bug attempts to contact a server and send it the following information:

• The IP address of the computer that fetched the Web Bug

This will be your IP address. Obviously if you have a fixed IP address this is worrying.

• 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

This is another reason why you shouldn't except all Cookies.
More on filtering Cookies

Web Bugs in e-mail can be used for:

• Finding out if a particular e-mail has been read and when it was read
• The IP address that viewed the mail
• How often an email is forwarded.

Pros/Cons

• They enable a web site to track ad promotions, and decide which one is best for a particular situation.
• Users of web bugs claim they are harmless. If this is so why are they hidden? Privacy advocates have discovered that when combined with third-party sources, Web Bugs can give marketers a large amount of information, right down to home address, and online account balances (Laudon, K. C. and Traver C. G. (2002). E-commerce: business, technology, society. USA: Addison Wesley).
• The security firm Intelytics has discovered that there are many types of Web Bugs, the most basic work with Cookies to transmit information about your browsing to third parties (like Doubleclick), others are 'executable' and install applications on your PC to collect information on documents containing key words (ibid). It's probably unlikely that main stream web sites uses these kind of bugs, it's the smaller, less scrupulous sites where your more likely to find this stuff. A survey by Cyveillance found that most Web Bugs were found on personal home pages that had adverts embedded.

For more Information:

Google search for Web Bugs
The Privacy Foundation - Web Bugs
Bugnosis
Security Space Web bug Report
   - Web Bug Count Site Report
   - Web Bug Traffic Count Report

Glossary Top

Outpost and the Outpost logo are ©Agnitum Software

This is an unofficial guide, the information expressed here may differ from Agnitum's. There is a support forum (no longer run by Agnitum, but by users) if you need more help this is a good place to start. Where information here conflicts with what Agnitum have told you always go with the information given to you by Agnitum.

Guide/site and images ©Stephen Cox