1130b656e5
This will make a number of things easier in the future, as well as (finally!) avoiding the Id-smashing problem which has plagued developers for so long. Boy, I'm glad we're not using sup anymore. This update would have been insane otherwise.
60 lines
2.1 KiB
Groff
60 lines
2.1 KiB
Groff
.\" $FreeBSD$
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.\" Copyright 1989 by the Massachusetts Institute of Technology.
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.\"
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.\" For copying and distribution information,
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.\" please see the file <Copyright.MIT>.
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.\"
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.TH FIX_KDB_KEYS 8 "Kerberos Version 4.0" "MIT Project Athena"
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.SH NAME
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fix_kdb_keys \- Secure Kerberos database by properly randomising keys
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.SH SYNOPSIS
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fix_kdb_keys
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.SH DESCRIPTION
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If you built your Kerberos database before receiving this distribution,
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the keys were randomly generated using the vulnerable version of
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the Kerberos random number generator. Therefore it is possible for
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an attacker to mount an attack to guess these values. If an attacker
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can determine the key for the
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.I krbtgt
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ticket, they can construct tickets claiming to be any Kerberos
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principal. Similarly if an attacker can obtain the
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.I changepw.kerberos
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key, they can change anyone's password.
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.PP
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This distribution has been patched to use the improved
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.IR des_new_random_key()
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routines instead of the old and cryptographically suspect
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.IR des_random_key().
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.PP
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The primary difference is that
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.IR des_random_key()
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uses a seeding
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technique which is predictable and therefore vulnerable. While
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.IR des_new_random_key()
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uses a feedback mechanism based on the Data Encryption Standard
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(DES) and is seeded with a secret (and therefore unknown to an
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attacker) value. This value is the secret database master key.
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.PP
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Running
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.I fix_kdb_keys
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on the KDC server will change these critical keys to new
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values using the newer random number generator. IMPORTANT: When this
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is done, all outstanding ticket granting tickets will
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immediately become invalid. This will be disruptive to your user
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community. It is recommended that this is done late at night or early
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in the morning before most users have logged in. Alternatively
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pre-announce a definitive time when you will run the program and
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inform the users that they will have to get new tickets at that time
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(using either
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.I kinit
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or simply by logging out and then in again).
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.SH DIAGNOSTICS
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Many, and descriptive.
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.SH FILES
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.TP 20n
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/etc/kerberosIV/principal.db
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DBM file containing database
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.TP
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/etc/kerberosIV/master_key
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Master key cache file.
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