Hi Guys,

I agree with Andrew.  The only risk is if your service is not using SSL as 
well.  In cases like that, it is trivial to intercept the cookie, and use it to 
gain access to the site the user was attempting to gain access to.  But, even 
this requires a high level of access to networks between the user and the 
service server.  i.e. Perhaps a disgruntled employee at an ISP somewhere in 
between.  So, even in the case when not using an SSL enabled service, it is 
pretty difficult to intercept a ticket.

----- "Andrew Petro" <[EMAIL PROTECTED]> wrote:
> Chris,
> 
> The ticket granting cookie is typically an SSL-vended, tightly-scoped
> 
> (just for your CAS server), session-scoped (expired by your browser
> when 
> your browser session ends) cookie.
> 
> I say typically because all these things are configurable, but I 
> strongly recommend you don't change the defaults on any of these
> aspects 
> of the cookie.
> 
> There are two perspectives to examine cookie security. One perspective
> 
> is security on the web.
> 
> Since the cookie is SSL-vended, the Adversary cannot obtain it by 
> evesdropping on the line. Since it is tightly scoped (and SSL-vended),
> 
> the browser will not re-present this cookie on requests to sites other
> 
> than the CAS server. Since the cookie is not used to authenticate to 
> other sites (rather, the cookie is re-presented to CAS, which then 
> issues a shorter-lived transactional service ticket conveyed via
> request 
> parameter on a redirect rather than as a cookie), other sites do not 
> have access to this cookie.
> 
> So, "How secure is the TGC?" The TGC is "very secure", in that 
> industry-standard methods for protecting session cookies are applied
> to 
> protect what is effectively a CAS server session cookie. It is no
> easier 
> for the Adversary to steal a TGC from the browser over the web than it
> 
> is to steal any other secure session cookie, such as that you use to 
> access your bank's account management web application during the
> course 
> of an active session.
> 
> 
> There's another perspective for considering TGC security -- what if
> the 
> Adversary has direct access to the end user's computer? What if the 
> computer is compromised, or physically stolen during the course of an
> 
> active session in which the TGC is still resident?
> 
> Since it is session-scoped, typical browsers will not commit it to
> disk 
> and will delete it when a browser session ends normally, so the window
> 
> of opportunity is narrow. Nonetheless, the popular expression among 
> computer security professionals goes something like "physical access
> to 
> the computer is equivalent to root access", and that is apt here. A 
> compromised web browser, operating system, or physically accessed 
> machine can have spyware installed, a compromised browser installed,
> to 
> capture the primary credentials when they are presented to CAS, to 
> capture TGCs, or really to do anything else. Compromised computers are
> a 
> bad thing. CAS makes this no worse, but it doesn't magically solve
> it.
> 
> To put this in perspective, if I access my online bank account web 
> interface from a compromised computer, I necessarily reveal all the 
> credentials necessary to access my account from that computer, at
> least 
> for the course of that session.
> 
> If one were inclined to implement all those fun rotating security 
> questions, distinctions between public and personal computers, IP 
> address tracking to prevent cookies from being presented from
> different 
> IP addresses during the course of a session (personally, I truly
> despise 
> this misfeature), while CAS doesn't tend to have these features out of
> 
> the box, it certainly offers an extensible platform in which they can
> be 
> implemented. Spring Web Flow for the win.
> 
> Andrew
> 
> 
> 
> 
> > Hi,
> >
> > I've successfully installed and configure CAS to use my LDAP user 
> > database. I'm almost on production stage :)
> >
> > My IT asked me about "How secure is the TGC?" meaning is it possible
> for 
> > a hacker to steal a TGC from a user browser, and use it to
> impersonate a 
> > user.
> >
> > I read in the doc and powerpoints that the TGC was 'private' and 
> > 'protected' but I dunno exactely what it means.
> >
> > Can anyone tell me more about TGC protection? How much are they
> secured?
> >
> > Best,
> >
> > Chris
> >
> > _______________________________________________
> > Yale CAS mailing list
> > [email protected]
> > http://tp.its.yale.edu/mailman/listinfo/cas
> >   
> 
> _______________________________________________
> Yale CAS mailing list
> [email protected]
> http://tp.its.yale.edu/mailman/listinfo/cas


__ 
    This communication is intended for the use of the recipient to whom it
    is addressed, and may contain confidential, personal, and or privileged
    information. Please contact us immediately if you are not the intended
    recipient of this communication, and do not copy, distribute, or take
    action relying on it. Any communications received in error, or
    subsequent reply, should be deleted or destroyed.
---
_______________________________________________
Yale CAS mailing list
[email protected]
http://tp.its.yale.edu/mailman/listinfo/cas

Reply via email to