[30038] in Kerberos
Re: Question about dns_lookup_realm and domain_realm
daemon@ATHENA.MIT.EDU (Jeffrey Altman)
Fri Jun 27 11:37:00 2008
X-Envelope-From: jaltman@secure-endpoints.com
X-MDaemon-Deliver-To: kerberos@mit.edu
Message-ID: <486507D0.2030409@secure-endpoints.com>
Date: Fri, 27 Jun 2008 11:31:28 -0400
From: Jeffrey Altman <jaltman@secure-endpoints.com>
MIME-Version: 1.0
To: ssorce@redhat.com
In-Reply-To: <1214579831.3822.276.camel@localhost.localdomain>
Cc: kerberos@mit.edu
Reply-To: jaltman@secure-endpoints.com
Content-Type: multipart/mixed; boundary="===============1987106160=="
Errors-To: kerberos-bounces@mit.edu
This is a cryptographically signed message in MIME format.
--===============1987106160==
Content-Type: multipart/signed; protocol="application/x-pkcs7-signature";
micalg=sha1; boundary="------------ms050703010601040700000408"
This is a cryptographically signed message in MIME format.
--------------ms050703010601040700000408
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Simo Sorce wrote:
>> There are several issues here. First, DNS TXT records are known to be
>> insecure.
>
> Jeff,
> this statements is interesting, how are TXT records "insecure" ?
I will refer you to the security considerations section of the internet
draft. Note that
the insecurity is one reason that the TXT record portion of the draft
was not
added to RFC 4120 as the DNS SRV records portion was.
http://tools.ietf.org/html/draft-ietf-krb-wg-krb-dns-locate-03
>
>> Turning
>> them on for use in realm resolution provides for convenience but at the
>> risk that your clients
>> can be redirected to a realm that you do not control.
>
> You can do the same with DNS poisoning, if you do not trust DNS any name
> resolution becomes "insecure".
> Isn't "validation" all about verifying the KDC is one we can really
> trust by using a trusted secret ?
If the host name resolves to a different IP address, the authentication
will fail.
>
>> Second, any domain_realm mapping for your domain .foo.com is going to
>> override the use
>> of DNS lookups. That is because local configuration data is considered
>> to be trustworthy
>> whereas DNS lookups are not.
>
> How is local configuration data trustworthy given that to resolve names
> to IPs we still rely on DNS ? Or do you also rely on /etc/hosts for most
> of the data ?
If the host name resolves to a different IP address, the authentication
will fail.
>
>> The safe way to add DNS TXT records back into the equation would be to
>> add the DNS TXT
>> lookup after the referrals request fails.
>
> Do we have information on which clients support referrals ?
> And are they implemented in MIT KDC (and how) ?
>
Heimdal, MIT, and Microsoft support referrals as implemented in Windows
Active Directory.
The IETF Kerberos working group is still working on an RFC for referrals.
http://www.ietf.org/internet-drafts/draft-ietf-krb-wg-kerberos-referrals-10.txt
Jeffrey Altman
--------------ms050703010601040700000408
Content-Type: application/x-pkcs7-signature; name="smime.p7s"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="smime.p7s"
Content-Description: S/MIME Cryptographic Signature
MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIJeTCC
AxcwggKAoAMCAQICEDsE+kRcmomW1hYG6BoqhGEwDQYJKoZIhvcNAQEFBQAwYjELMAkGA1UE
BhMCWkExJTAjBgNVBAoTHFRoYXd0ZSBDb25zdWx0aW5nIChQdHkpIEx0ZC4xLDAqBgNVBAMT
I1RoYXd0ZSBQZXJzb25hbCBGcmVlbWFpbCBJc3N1aW5nIENBMB4XDTA4MDUzMDE5MTUyOVoX
DTA5MDUzMDE5MTUyOVowczEPMA0GA1UEBBMGQWx0bWFuMRUwEwYDVQQqEwxKZWZmcmV5IEVy
aWMxHDAaBgNVBAMTE0plZmZyZXkgRXJpYyBBbHRtYW4xKzApBgkqhkiG9w0BCQEWHGphbHRt
YW5Ac2VjdXJlLWVuZHBvaW50cy5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIB
AQCtf5bVJdYFtHIrV2XALpA5oaMu7FPYU7RP7vJhd8Cu9Kd9ud2crX2pHK4avuPaYb4Vg9qI
zPrPadePhJ3OWwNt1ZlUlpc5URnOfpg/I9iymZBUSnCFVLuIvoncacqyUlzqdYEF8XGEoEL6
6bj8uoCSX0D7ZjZiAS8993NvgiPYpf10acMyWQ4max+P7Wg9T03Nw2F6EsmP6gWxBRsekTXe
N6QjJdvaK0846lDqeBFoCEzIUMQXj2kiXVPCPEdxPc/L1sDMYf0GLaDIg8qyThpGd0X6DwfK
3RWcMy8DV7Q5Z+jSEdPn5X0l4anOTrjr3IwE57MC3bVs0EEpUODTzftnAgMBAAGjOTA3MCcG
A1UdEQQgMB6BHGphbHRtYW5Ac2VjdXJlLWVuZHBvaW50cy5jb20wDAYDVR0TAQH/BAIwADAN
BgkqhkiG9w0BAQUFAAOBgQA9kndmeLrdQOUbhNGGms/FnfDyraH4OjA4PIIMOCbGWK0YXczs
/Fqn4XkT70SG4s8v4Zg6TaAcJrZBVcZQXyzrhlF2Zev/g69zZMHQe+2r4i/3FBVKAtFCoea1
vgwJ5TfZYlKvt4D0Z4zexu9Y0VwCIR4plWjVD76zC2CGB/2fhjCCAxcwggKAoAMCAQICEDsE
+kRcmomW1hYG6BoqhGEwDQYJKoZIhvcNAQEFBQAwYjELMAkGA1UEBhMCWkExJTAjBgNVBAoT
HFRoYXd0ZSBDb25zdWx0aW5nIChQdHkpIEx0ZC4xLDAqBgNVBAMTI1RoYXd0ZSBQZXJzb25h
bCBGcmVlbWFpbCBJc3N1aW5nIENBMB4XDTA4MDUzMDE5MTUyOVoXDTA5MDUzMDE5MTUyOVow
czEPMA0GA1UEBBMGQWx0bWFuMRUwEwYDVQQqEwxKZWZmcmV5IEVyaWMxHDAaBgNVBAMTE0pl
ZmZyZXkgRXJpYyBBbHRtYW4xKzApBgkqhkiG9w0BCQEWHGphbHRtYW5Ac2VjdXJlLWVuZHBv
aW50cy5jb20wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQCtf5bVJdYFtHIrV2XA
LpA5oaMu7FPYU7RP7vJhd8Cu9Kd9ud2crX2pHK4avuPaYb4Vg9qIzPrPadePhJ3OWwNt1ZlU
lpc5URnOfpg/I9iymZBUSnCFVLuIvoncacqyUlzqdYEF8XGEoEL66bj8uoCSX0D7ZjZiAS89
93NvgiPYpf10acMyWQ4max+P7Wg9T03Nw2F6EsmP6gWxBRsekTXeN6QjJdvaK0846lDqeBFo
CEzIUMQXj2kiXVPCPEdxPc/L1sDMYf0GLaDIg8qyThpGd0X6DwfK3RWcMy8DV7Q5Z+jSEdPn
5X0l4anOTrjr3IwE57MC3bVs0EEpUODTzftnAgMBAAGjOTA3MCcGA1UdEQQgMB6BHGphbHRt
YW5Ac2VjdXJlLWVuZHBvaW50cy5jb20wDAYDVR0TAQH/BAIwADANBgkqhkiG9w0BAQUFAAOB
gQA9kndmeLrdQOUbhNGGms/FnfDyraH4OjA4PIIMOCbGWK0YXczs/Fqn4XkT70SG4s8v4Zg6
TaAcJrZBVcZQXyzrhlF2Zev/g69zZMHQe+2r4i/3FBVKAtFCoea1vgwJ5TfZYlKvt4D0Z4ze
xu9Y0VwCIR4plWjVD76zC2CGB/2fhjCCAz8wggKooAMCAQICAQ0wDQYJKoZIhvcNAQEFBQAw
gdExCzAJBgNVBAYTAlpBMRUwEwYDVQQIEwxXZXN0ZXJuIENhcGUxEjAQBgNVBAcTCUNhcGUg
VG93bjEaMBgGA1UEChMRVGhhd3RlIENvbnN1bHRpbmcxKDAmBgNVBAsTH0NlcnRpZmljYXRp
b24gU2VydmljZXMgRGl2aXNpb24xJDAiBgNVBAMTG1RoYXd0ZSBQZXJzb25hbCBGcmVlbWFp
bCBDQTErMCkGCSqGSIb3DQEJARYccGVyc29uYWwtZnJlZW1haWxAdGhhd3RlLmNvbTAeFw0w
MzA3MTcwMDAwMDBaFw0xMzA3MTYyMzU5NTlaMGIxCzAJBgNVBAYTAlpBMSUwIwYDVQQKExxU
aGF3dGUgQ29uc3VsdGluZyAoUHR5KSBMdGQuMSwwKgYDVQQDEyNUaGF3dGUgUGVyc29uYWwg
RnJlZW1haWwgSXNzdWluZyBDQTCBnzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEAxKY8VXNV
+065yplaHmjAdQRwnd/p/6Me7L3N9VvyGna9fww6YfK/Uc4B1OVQCjDXAmNaLIkVcI7dyfAr
hVqqP3FWy688Cwfn8R+RNiQqE88r1fOCdz0Dviv+uxg+B79AgAJk16emu59l0cUqVIUPSAR/
p7bRPGEEQB5kGXJgt/sCAwEAAaOBlDCBkTASBgNVHRMBAf8ECDAGAQH/AgEAMEMGA1UdHwQ8
MDowOKA2oDSGMmh0dHA6Ly9jcmwudGhhd3RlLmNvbS9UaGF3dGVQZXJzb25hbEZyZWVtYWls
Q0EuY3JsMAsGA1UdDwQEAwIBBjApBgNVHREEIjAgpB4wHDEaMBgGA1UEAxMRUHJpdmF0ZUxh
YmVsMi0xMzgwDQYJKoZIhvcNAQEFBQADgYEASIzRUIPqCy7MDaNmrGcPf6+svsIXoUOWlJ1/
TCG4+DYfqi2fNi/A9BxQIJNwPP2t4WFiw9k6GX6EsZkbAMUaC4J0niVQlGLH2ydxVyWN3amc
OY6MIE9lX5Xa9/eH1sYITq726jTlEBpbNU1341YheILcIRk13iSx0x1G/11fZU8xggNkMIID
YAIBATB2MGIxCzAJBgNVBAYTAlpBMSUwIwYDVQQKExxUaGF3dGUgQ29uc3VsdGluZyAoUHR5
KSBMdGQuMSwwKgYDVQQDEyNUaGF3dGUgUGVyc29uYWwgRnJlZW1haWwgSXNzdWluZyBDQQIQ
OwT6RFyaiZbWFgboGiqEYTAJBgUrDgMCGgUAoIIBwzAYBgkqhkiG9w0BCQMxCwYJKoZIhvcN
AQcBMBwGCSqGSIb3DQEJBTEPFw0wODA2MjcxNTMxMjhaMCMGCSqGSIb3DQEJBDEWBBS9Q3bv
u62P7uo/DgbPMM4skxMxxDBSBgkqhkiG9w0BCQ8xRTBDMAoGCCqGSIb3DQMHMA4GCCqGSIb3
DQMCAgIAgDANBggqhkiG9w0DAgIBQDAHBgUrDgMCBzANBggqhkiG9w0DAgIBKDCBhQYJKwYB
BAGCNxAEMXgwdjBiMQswCQYDVQQGEwJaQTElMCMGA1UEChMcVGhhd3RlIENvbnN1bHRpbmcg
KFB0eSkgTHRkLjEsMCoGA1UEAxMjVGhhd3RlIFBlcnNvbmFsIEZyZWVtYWlsIElzc3Vpbmcg
Q0ECEDsE+kRcmomW1hYG6BoqhGEwgYcGCyqGSIb3DQEJEAILMXigdjBiMQswCQYDVQQGEwJa
QTElMCMGA1UEChMcVGhhd3RlIENvbnN1bHRpbmcgKFB0eSkgTHRkLjEsMCoGA1UEAxMjVGhh
d3RlIFBlcnNvbmFsIEZyZWVtYWlsIElzc3VpbmcgQ0ECEDsE+kRcmomW1hYG6BoqhGEwDQYJ
KoZIhvcNAQEBBQAEggEAfH5uScHGWr6VeIRkLchnv4h4NXzedBqQGSF9Bdk/YgTaJHxgtwjz
x/d+cebxbZlIuYgbx6Ygt5PXCRW3B/UzNtjnpbXPzcZKXYYLm0Le30+rFvu4kLv8JWPxne6I
dcJDwOTQJ1WUz0pZj6v3doLGAOGGqEVd6mcsxOgjdNgyyxjd9ZCIKqTsCfZMTCIgoopZUFXD
HVzcf9p7a8RY0s+7SRur9ZmV2kKHB+SD6UWKGjnT0bj8L258+IQy6KnKxaa0bv/UIIS/vR4A
WV7hDVG1ieNaGtPfO2Rm6pK5tJgKjEPC3slYy+WlHKMegQEfUVlhfp+6vmYBXoZ7fMIBciGa
LwAAAAAAAA==
--------------ms050703010601040700000408--
--===============1987106160==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
________________________________________________
Kerberos mailing list Kerberos@mit.edu
https://mailman.mit.edu/mailman/listinfo/kerberos
--===============1987106160==--
