Page 3 - May_1_Newsletter_2024

Alan started the presentation by showing tracking cookies in use. Running a version of Firefox, with the Collu-
sion add-in loaded http://www.mozilla.org/en-US/collusion/ he surfed to just three web sites, and showed how
cookies loaded via one site were linked up with cookies from other sites, enabling advertisers and others, to
track the sessions around the internet.

He then went on to explain

What cookies are
Where you can find them in your PC

Why they are needed in some cases
What you can do about them

Alan then discussed the various types of cookies. They can be classified by how long they last, and where they
come from. The two types of "timed" cookies are Session cookies and Persistent cookies. Session cookies
should expire at the end of your session, (but be aware, this is when you close down your browser, not when
you leave that site). Persistent cookies will stay on your PC for a long time, maybe a year, maybe many years.

In terms of the source of cookies, the types are First party cookies and Third-party cookies. First party ones are
set by the site that you are visiting, third party ones are set by another site. Broadly speaking, first party cookies
tend to be OK and required, third party ones tend to be for tracking/advertising etc. A First party cookie may be
loaded when you visit a web page so that the web site can follow you around the site, know what you are look-
ing at, keep track of anything you want to buy etc. The third-party cookie will be loaded with a part of the page
coming from another site. This may be an associated site, for example, Amazon seems to keep the pictures of
goods on a separate server, so when you look at something on www.amazon.co.uk, it will load pictures from
images.amazon.com. These pictures may include a cookie, but it is from a third party. Other items on the page
may come from a totally different company, e.g. doubleclick.net, which supplies the adverts appearing on
many web sites. You may also see cookies from Google Analytics, which the web site may be using to track
visitors.

Alan also talked about the work that Steve Gibson of Gibson Research Corporation has been doing and showed
us Steve's Cookie Forensics Page This site has a lot more information about cookies, and can test your browser
to see which types of cookies are being accepted and returned.

https://www.grc.com/cookies/cookies.htm .

He showed test results from a new install of Firefox (which was accepting all types of cookie by default), and
the results from his normal browser configuration which refuses third party cookies, but accepts first party
cookies. You can lock most browsers down even further to either only accept session cookies, or accept them
for the session only, even if they are defined as persistent. Another option in some browsers is to clear all cook-
ies automatically when you shut down.