[2322] in Kerberos
kerberizing xlock ???
daemon@ATHENA.MIT.EDU (Barry Jaspan)
Fri Oct 30 16:48:50 1992
Date: Fri, 30 Oct 92 16:23:58 -0500
From: "Barry Jaspan" <bjaspan@Athena.MIT.EDU>
To: greg@duke.cs.unlv.edu
Cc: hendrick@neptune.ctron.com, kerberos@Athena.MIT.EDU
In-Reply-To: Greg Wohletz's message of Thu, 29 Oct 92 10:28:27 -0800 <9210302035.AA24770@Athena.MIT.EDU>
Date: Thu, 29 Oct 92 10:28:27 -0800
From: Greg Wohletz <greg@duke.cs.unlv.edu>
>The solution to this problem is for login to verify the tgt by using
>it to acquire a service ticket with a known key and comparing the
>results.
Another solution is to run a kerberized server on some physically secure
machine (the kerberos server for example) which the login process attempts
to do mutual authentication with using the tgt it got.
No, that does not solve the problem. It makes the attack exactly
three times as difficult; however, thrice zero security is still zero
security.
If I can create a fake tgt response from Kerberos, then presumably I
can create a fake service ticket response from Kerberos, *and* I can
fake a response from the verification service you propose. Thus I can
still fake out the login program on the attacked host.
Barry
