[2447] in Kerberos
Why zero out key variables?
daemon@ATHENA.MIT.EDU (Clifford Neuman)
Wed Dec 9 16:46:00 1992
Date: Wed, 9 Dec 92 13:24:23 PST
From: Clifford Neuman <bcn@ISI.EDU>
To: Jim_Miller@suite.com
Cc: kerberos@MIT.EDU
In-Reply-To: Jim Miller's message of Wed, 9 Dec 92 15:16:58 -0600 <9212092117.AA10271@bilbo.suite.com>
From: jim@bilbo.suite.com (Jim Miller)
Date: Wed, 9 Dec 92 15:16:58 -0600
I've been playing around the source code for Kerberos V4 and I notice
that in many places that program variables that are used to hold
encryption keys are zeroed out immediately after use. Also, some
(but not all) of the buffers that are used to hold tickets are also
zeroed out after use.
Why is this done? Especially considering the fact the tickets are
written to the file system. Is the file system more secure than a
process's memory space?
The reason for this is that a ticket can only be used until it
expires. The users secret key can be used until the user changes the
password.
~ Cliff
