Adelphia said:
Does anyone know of techniques that actually analyze a cookie to see if it
is "good"?
From what I see of the blacklists for "bad" cookies, they are by domain.
That is, how the domain uses their cookie is bad for the user. It's just
data within a cookie, so even a simple and innocuous looking string like
"gh89llll" might not mean anything to the user that had a utility to look
into the cookie but to the site it is the encoded string telling that site
when you last visited them, or where you came from, or other encoded
information. It would be like trying to use Notepad to look at an SQL
database: you would see a bunch a values but YOU wouldn't know how they were
used or what they meant.
From what I recall of cookies, a cookie lists its owning domain. Only that
domain can use that cookie. So a "bad" site cannot try to hide its cookie
under some other domain's name (by changing the domain field within the
cookie) because then that "bad" site couldn't use their own cookie. So
whitelisting works to let you keep only those cookies that you really need.
IE already has a whitelisting feature (Internet Options -> Privacy ->
Sites). You can add good domains with the Allow attribute and then
configure IE to block all other cookies. If you find a site where you want
to keep their cookie then you can add them to the Allow list. However, this
doesn't help for sites where you don't want to permanently save their cookie
but would like to permit it as a per-session cookie. Their site may not
function properly without their cookie, so let them have it while you are
there, and then forcibly delete it after you leave (i.e., if not whitelisted
in the Allow list, force all other cookies to be per-session cookies).
I have maybe less than a dozen domains where I trust their use of their
cookies. Management of a dozen good sites - and which are of MY choosing -
is a lot easier than managing a blacklist of thousands of domains unless, of
course, you are lazy and let someone else decide for you what sites are
"bad". There are already plenty of cookie managers available to makeup for
IE's lack of per-session handling of non-whitelisted cookies. IE does have
a whitelist (by setting Allow on a domain) but it doesn't have a means of
forcing all other cookies to be per-session cookies.