Ritter, Marcel (RRZE)
2015-Aug-18 20:28 UTC
[Samba] Samba 4 DC - no AES kerberos tickets - only arcfour
Hi, I’ve been running a samba 4 DC for quite some time now, and while testing some kerberos related stuff, I noticed that all kerberos tickets I can get from the DC are of encryption type ?arcfour-hmac-md5“: # kinit testuser1 testuser1 at S4DOM.TEST's Password: # klist -v Credentials cache: FILE:/tmp/krb5cc_0 Ticket etype: arcfour-hmac-md5, kvno 1 I can create keytabs containing aes128/aes256 keys (besides the arcfour ones), but if I’m trying to use them (e.g. for NFS client/server) the ccache files only report usage of ?arcfour-hmac-md5“. Trying to remove non-aes keys from keytab, or limiting supported types will result in an error like this: # kinit -e aes256-cts-hmac-sha1-96 Administrator Administrator at S4DOM.TEST's Password: kinit: krb5_get_init_creds: KDC has no support for encryption type # kinit -e arcfour-hmac-md5 Administrator Administrator at S4DOM.TEST's Password: ⇒ Succeeds, with arcfour ticket This looks like the samba 4 DC does not offer AES encryption types at all. So I tried to raise the function level (if i recall correctly AES should be enabled with 2008 R2), however the behaviour stays the same. # samba-tool domain level raise --forest-level 2008_R2 --domain-level 2008_R2 I've reproduced this with Ubuntu 14.04.3 / Samba 4.1.6, but also with a current samba.git-Checkout - no difference so far. What am I missing here? Do I need to take some extra steps after the domain level raise to use AES? Bye, Marcel
Trever L. Adams
2015-Aug-19 03:54 UTC
[Samba] Samba 4 DC - no AES kerberos tickets - only arcfour
On 08/18/2015 02:28 PM, Ritter, Marcel (RRZE) wrote:> Hi, > > I’ve been running a samba 4 DC for quite some time now, and while testing some kerberos related stuff, I noticed that all kerberos tickets I can get from the DC are of encryption type ?arcfour-hmac-md5“: > > # kinit testuser1 > testuser1 at S4DOM.TEST's Password: > > # klist -v > Credentials cache: FILE:/tmp/krb5cc_0 > Ticket etype: arcfour-hmac-md5, kvno 1 > > I can create keytabs containing aes128/aes256 keys (besides the arcfour ones), but if I’m trying to use them (e.g. for NFS client/server) the ccache files only report usage of ?arcfour-hmac-md5“. > > Trying to remove non-aes keys from keytab, or limiting supported types will result in an error like this: > > # kinit -e aes256-cts-hmac-sha1-96 Administrator > Administrator at S4DOM.TEST's Password: > kinit: krb5_get_init_creds: KDC has no support for encryption type > > # kinit -e arcfour-hmac-md5 Administrator > Administrator at S4DOM.TEST's Password: > ⇒ Succeeds, with arcfour ticket > > This looks like the samba 4 DC does not offer AES encryption types at all. > > So I tried to raise the function level (if i recall correctly AES should be enabled with 2008 R2), however the behaviour stays the same. > > # samba-tool domain level raise --forest-level 2008_R2 --domain-level 2008_R2 > > I've reproduced this with Ubuntu 14.04.3 / Samba 4.1.6, but also with a current samba.git-Checkout - no difference so far. > > What am I missing here? > Do I need to take some extra steps after the domain level raise to use AES? > > Bye, > Marcel >I recently had this problem. Have users change their passwords. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: OpenPGP digital signature URL: <http://lists.samba.org/pipermail/samba/attachments/20150818/f8a05c24/signature.sig>
Ritter, Marcel (RRZE)
2015-Aug-19 06:02 UTC
[Samba] Samba 4 DC - no AES kerberos tickets - only arcfour
Hi Trever,
things improved after resetting user/machine passwords, however only the session
key is using aes256 now, the ticket itself is still arcfour:
root at ubuntu1:~# kinit user09999
user09999 at S4DOM.TEST's Password:
root at ubuntu1:~# klist -v
Credentials cache: FILE:/tmp/krb5cc_0
Principal: user09999 at S4DOM.TEST
Cache version: 4
Server: krbtgt/S4DOM.TEST at S4DOM.TEST
Client: user09999 at S4DOM.TEST
Ticket etype: arcfour-hmac-md5, kvno 1
Session key: aes256-cts-hmac-sha1-96
Ticket length: 1074
Auth time: Aug 19 07:53:10 2015
End time: Aug 19 17:53:04 2015
Ticket flags: enc-pa-rep, pre-authent, initial, proxiable, forwardable
Addresses: addressless
Is there something like a "domain password/secret" that I need to
reset too in order to get aes encryption for everything?
If so, how do I do that?
I also cross-checked this with our windows AD (same client) and I get an AES
only ticket/key:
<...>
Ticket etype: aes256-cts-hmac-sha1-96, kvno 2
Ticket length: 2278
<...>
Any other ideas?
Bye,
Marcel
-----Ursprüngliche Nachricht-----
Von: Trever L. Adams [mailto:trever at middleearth.sapphiresunday.org]
Gesendet: Mittwoch, 19. August 2015 05:55
An: Ritter, Marcel (RRZE) <marcel.ritter at fau.de>; samba at
lists.samba.org
Betreff: Re: [Samba] Samba 4 DC - no AES kerberos tickets - only arcfour
On 08/18/2015 02:28 PM, Ritter, Marcel (RRZE) wrote:> Hi,
>
> I’ve been running a samba 4 DC for quite some time now, and while testing
some kerberos related stuff, I noticed that all kerberos tickets I can get from
the DC are of encryption type ?arcfour-hmac-md5“:
>
> # kinit testuser1
> testuser1 at S4DOM.TEST's Password:
>
> # klist -v
> Credentials cache: FILE:/tmp/krb5cc_0
> Ticket etype: arcfour-hmac-md5, kvno 1
>
> I can create keytabs containing aes128/aes256 keys (besides the arcfour
ones), but if I’m trying to use them (e.g. for NFS client/server) the ccache
files only report usage of ?arcfour-hmac-md5“.
>
> Trying to remove non-aes keys from keytab, or limiting supported types will
result in an error like this:
>
> # kinit -e aes256-cts-hmac-sha1-96 Administrator
> Administrator at S4DOM.TEST's Password:
> kinit: krb5_get_init_creds: KDC has no support for encryption type
>
> # kinit -e arcfour-hmac-md5 Administrator
> Administrator at S4DOM.TEST's Password:
> ⇒ Succeeds, with arcfour ticket
>
> This looks like the samba 4 DC does not offer AES encryption types at all.
>
> So I tried to raise the function level (if i recall correctly AES should be
enabled with 2008 R2), however the behaviour stays the same.
>
> # samba-tool domain level raise --forest-level 2008_R2 --domain-level
2008_R2
>
> I've reproduced this with Ubuntu 14.04.3 / Samba 4.1.6, but also with a
current samba.git-Checkout - no difference so far.
>
> What am I missing here?
> Do I need to take some extra steps after the domain level raise to use AES?
>
> Bye,
> Marcel
>
I recently had this problem. Have users change their passwords.