Re: YA cookie draft, v2.21

koen@win.tue.nl (Koen Holtman) wrote:
  > >
  > >The latest draft of the cookie spec. is at
  > >	http://www.research.att.com/~dmk/cookie.html
  > 
  > Only two comments:
  > 
  > 
  > #4.3.5  Sending Cookies in Unverifiable Transactions  Users must have      |
  > #control over sessions in order to insure privacy.
  >                                    ^^^^^^
  > 
  > Shouldn't this be `assure'?
Well, maybe "ensure".
  > 
  > 
  > #8.2  Cookie Spoofing
  > #
  > [...]
  > #Note that a server at cracker.edu could send a cookie to the client and   |
  > #subsequently get both of the cookies in the preceding example as well as  |
  > #its own.
  > 
  > I was confused by this, and after re-reading it twice, I think this is
  > wrong.  I believe this should be:
  > 
  >  Note that a server called cracker.edu could send a cookie to the
  >  client without an explicit domain, and subsequently get the second
  >  cookie in the preceding example as well as its own.

No.  Actually, the whole passage must be dropped.  I put it in when Ted
Hardie observed the problem as stated.  But we've fixed the problem by
requiring explicit leading dots in Domain=.

If a server at cracker.edu sent a cookie to the client, it would only
get back its own cookie.  It could only set Domain=cracker.edu, which
is also the default Domain.  (Domain=.cracker.edu would not
domain-match the host name (cracker.edu), and the cookie would be
discarded.) Since cookies with domains victim.cracker.edu and
.cracker.edu do not domain-match "cracker.edu", neither cookie in the
example would get send to the bad guy.

Dave

Received on Tuesday, 23 April 1996 12:48:20 UTC