Re: spoofing cookies

Jonathan Stark (stark@truste.org)
Mon, 6 Oct 1997 12:12:42 -0700 (PDT)


> 
> I recently asked about how you could use cookies to make some
> lightweight security, and got the answer that cookies are easy to spoof
> and thus very insecure. You can just as a server ask for another servers
> cookie, and then you can spoof the original server. 
> 
> My idea was that this kind of spoofing could be prevented, if
> the client stored the cookie with an identification of the server.
> Then to spoof you need to do IP spoofing, which can be done,
> but which is close to being criminal.
> 
> Is that something to list in a "best practice" section somewhere?
> 
> keld
> 

This concept works well with static IP addresses, but totally 
breaks when you get a different dynamically allocated IP address the 
next time you dial into your ISP.  

The IP is different, but no spoofing has occured, and the cookie
is valid.

Jonathan