Re: How do web beacons work?

[Michal Zalewski <lcamtuf () coredump cx>]

On Thu, 6 Jan 2005, Lance Spitzner wrote:

> Okay, what exactly is a web beacon?

Looks like an euphemism made up by PR drones. It appears to be a classic
privacy-invading web bug. Kudos to them; the word "beacon" sounds great -
so reassuring and harmless; and so similar to another great word, "bacon".

Yahoo! describes two uses of this web bacon thingy:

  1) Web bug in a HTML mail - when the file is requested, it would appear
     that you just opened (and read) a mail we sent you earlier. Can be
     used to verify addresses used for spamming, or just shamelessly
     track users.

     You know, as in:
     <IMG SRC="http://lcamtuf.coredump.cx/lance_just_read_this_mail.jpg";
     HEIGHT=1 WIDTH=1>

  2) Third-party domain bug (or banner or whatnot) on a HTML page.
     A banner from the same supplier placed on various sites can be used,
     through cookies, to track your activity across domains (checking
     Referer or unique names in banner URI).

See http://www.allaboutcookies.org/faqs/beacons.html and so on.

-- 
------------------------- bash$ :(){ :|:&};: --
 Michal Zalewski * [http://lcamtuf.coredump.cx]
    Did you know that clones never use mirrors?
--------------------------- 2005-01-06 17:41 --

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