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Re: cpw ignoring password policies
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Greg Hudson
Aug 12, 2020, 11:52:37 AM8/12/20
to Dario García Díaz-Miguel, kerb...@mit.edu
On 8/12/20 5:39 AM, Dario García Díaz-Miguel wrote:
> kadmin -k -t $KEYTABLOCATION -p $SERVICEPRINCIPAL -q "cpw $PRINCIPAL -pw $PASSWORD"
>
> What we found is that this command ignores the password policy assigned to the principal, including all the complexity rules and history options. No matter if the command is launched in a kadmin console interactive mode, policies are totally ignored.
>
> If we use:
>
> kpasswd $PRINCIPAL
That's unexpected, and it's not the behavior I see in a test environment:
$ kadmin.local addpol -minlength 6 testpol
$ kadmin.local modprinc -policy testpol user
$ kadmin -k -p user/admin cpw -pw pw user
change_password: Password is too short while changing password for
"us...@KRBTEST.COM".
$ kadmin.local cpw -pw pw user
change_password: Password is too short while changing password for
"us...@KRBTEST.COM".
What software and version is running on the kadmin server?
> kadmin -k -t $KEYTABLOCATION -p $SERVICEPRINCIPAL -q "cpw $PRINCIPAL -pw $PASSWORD"
>
> What we found is that this command ignores the password policy assigned to the principal, including all the complexity rules and history options. No matter if the command is launched in a kadmin console interactive mode, policies are totally ignored.
>
> If we use:
>
> kpasswd $PRINCIPAL
That's unexpected, and it's not the behavior I see in a test environment:
$ kadmin.local addpol -minlength 6 testpol
$ kadmin.local modprinc -policy testpol user
$ kadmin -k -p user/admin cpw -pw pw user
change_password: Password is too short while changing password for
"us...@KRBTEST.COM".
$ kadmin.local cpw -pw pw user
change_password: Password is too short while changing password for
"us...@KRBTEST.COM".
What software and version is running on the kadmin server?
Dario García Díaz-Miguel
Aug 13, 2020, 10:28:11 AM8/13/20
to Greg Hudson, kerb...@mit.edu
Hello Greg,
Thank you so much for your quick reply.
What I found with some tests is that while length and character classes rules are being correctly applying using cpw, other rules like minlife are not respected.
For example, I set a policy with the following rules:
Policy: TEST
Maximum password life: 2629800
Minimum password life: 864000
Minimum password length: 10
Minimum number of password character classes: 3
Number of old keys kept: 4
Maximum password failures before lockout: 4
Password failure count reset interval: 0 days 03:00:00
Password lockout duration: 0 days 03:00:00
I can change all the time the password of the principal with that policy applied despite the minimum password life described.
Also I'm able to apply old passwords and the history is not being respected, but I'm afraid that's the expected behavior because of the LDAP database module.
Using kpasswd, then the reject message is correctly prompted:
Password change rejected: Password cannot be changed because it was changed too recently. Please wait until Sun Aug 23 07:42:10 2020 before you change it.
If you need to change your password before then, contact your system security administrator.
I understand that cpw is more like the administration password changing tool and in order to be able to change the password whenever it requires by the system administrator, the minimum password life is not being applied.
But then, Any ideas about how could we proceed?
Our kerberos version: 1.12.5-40.34.1
OS: Suse 12 SP3
We are not able to install more recent software due to some customer requirements, although would be apprecited to know if further versions have a different behavior.
Dario Garcia
Díaz-Miguel
GGCS-SES Unit
GGCS SKMF Infrastructure Division
GMV
C\ de Isaac Newton, 11
28760, Tres Cantos, Madrid
España
+34 918 07 21 00
+34 918 07 21 99
www.gmv.com
-----Mensaje original-----
De: Greg Hudson [mailto:ghu...@mit.edu]
Enviado el: miércoles, 12 de agosto de 2020 17:52
Para: Dario García Díaz-Miguel <dgd...@gmv.com>; kerb...@mit.edu
Asunto: Re: cpw ignoring password policies
P Please consider the environment before printing this e-mail.
Thank you so much for your quick reply.
What I found with some tests is that while length and character classes rules are being correctly applying using cpw, other rules like minlife are not respected.
For example, I set a policy with the following rules:
Policy: TEST
Maximum password life: 2629800
Minimum password life: 864000
Minimum password length: 10
Minimum number of password character classes: 3
Number of old keys kept: 4
Maximum password failures before lockout: 4
Password failure count reset interval: 0 days 03:00:00
Password lockout duration: 0 days 03:00:00
I can change all the time the password of the principal with that policy applied despite the minimum password life described.
Also I'm able to apply old passwords and the history is not being respected, but I'm afraid that's the expected behavior because of the LDAP database module.
Using kpasswd, then the reject message is correctly prompted:
Password change rejected: Password cannot be changed because it was changed too recently. Please wait until Sun Aug 23 07:42:10 2020 before you change it.
If you need to change your password before then, contact your system security administrator.
I understand that cpw is more like the administration password changing tool and in order to be able to change the password whenever it requires by the system administrator, the minimum password life is not being applied.
But then, Any ideas about how could we proceed?
Our kerberos version: 1.12.5-40.34.1
OS: Suse 12 SP3
We are not able to install more recent software due to some customer requirements, although would be apprecited to know if further versions have a different behavior.
Dario Garcia
Díaz-Miguel
GGCS-SES Unit
GGCS SKMF Infrastructure Division
GMV
C\ de Isaac Newton, 11
28760, Tres Cantos, Madrid
España
+34 918 07 21 00
+34 918 07 21 99
www.gmv.com
-----Mensaje original-----
De: Greg Hudson [mailto:ghu...@mit.edu]
Enviado el: miércoles, 12 de agosto de 2020 17:52
Para: Dario García Díaz-Miguel <dgd...@gmv.com>; kerb...@mit.edu
Asunto: Re: cpw ignoring password policies
Greg Hudson
Aug 13, 2020, 11:36:32 AM8/13/20
to Dario García Díaz-Miguel, kerb...@mit.edu
On 8/13/20 1:51 AM, Dario García Díaz-Miguel wrote:
> I can change all the time the password of the principal with that policy applied despite the minimum password life described.
That's true. The kadmin server code deliberately only checks the
> I can change all the time the password of the principal with that policy applied despite the minimum password life described.
minimum life if a principal is changing its own password.
> Also I'm able to apply old passwords and the history is not being respected, but I'm afraid that's the expected behavior because of the LDAP database module.
> I understand that cpw is more like the administration password changing tool and in order to be able to change the password whenever it requires by the system administrator, the minimum password life is not being applied.
> But then, Any ideas about how could we proceed?
then authenticate with it:
kinit -k -c somefilename -t KDB: -S kadmin/admin username
kadmin -c somefilename -q "cpw -pw password username"
kinit -t KDB: support was added in release 1.9, so should be available.
Dario García Díaz-Miguel
Aug 14, 2020, 10:36:29 AM8/14/20
to Greg Hudson, kerb...@mit.edu
Hi Greg,
Thank you so much for your Support and quick replies, really appreciated.
> That's true. The kadmin server code deliberately only checks the minimum life if a principal is changing its own password.
Indeed. It makes sense.
> Right, LDAP password history is implemented in release 1.15 but not in 1.12.
I will discuss this point with the project leaders to see if we can upgrade the krb5 version since this is a requirement as well as some supported features in further version such as spake preauth or aes256.
> I guess you could print a kadmin ticket for the user from the KDB and then authenticate with it:
>
> kinit -k -c somefilename -t KDB: -S kadmin/admin username
> kadmin -c somefilename -q "cpw -pw password username"
> kinit -t KDB: support was added in release 1.9, so should be available.
Perfect. This seems to work for me when running the commands as root user. It checks the minimum password life and rejects the change.
But, since the user who ran the script files is wwwrun, I'm getting the following message:
$/usr/lib/mit/bin/kinit -k -c /home/wwwrun/arashimkrbcc -t KDB: -S kadmin/admin arashim
kinit: No such file or directory while setting up KDB keytab for realm TEST.COM
I've tried with several users and path locations for the cache credentials file but not succedeed. Using sudo before command works flawlessly.
What files or directories this command checks other than the cache credentials created, requiring to grant some permissions to the user who is running it?
According to kinit man, the "KDB:" option looks directly inside the Kerberos Database. So, this should be a permissions issue to access to the Kerberos Database. But honestly, I don't know what files and which should I grant to read to wwwrun to make this work avoiding to hardcode the root password in plain text. I'm not being able to track it on logs either.
Since we built the Kerberos Database on OpenLDAP krbContainer, what file is the one which non-root user should be able to read in order to make this work?
Another option regarding with the idea you sent me could be create a keytab owned by wwwrun to store all users keys and use. However I would prefer to ask the ticket looking directly into the KDB instead of using another keytab for all users. It could be a headache to maintain and totally a bad practice.
Again, thank you so much for your help.
Kind Regards.
Dario Garcia
Díaz-Miguel
GGCS-SES Unit
GGCS SKMF Infrastructure Division
GMV
C\ de Isaac Newton, 11
28760, Tres Cantos, Madrid
España
+34 918 07 21 00
+34 918 07 21 99
www.gmv.com
-----Mensaje original-----
De: Greg Hudson [mailto:ghu...@mit.edu]
Enviado el: jueves, 13 de agosto de 2020 17:36
Thank you so much for your Support and quick replies, really appreciated.
> That's true. The kadmin server code deliberately only checks the minimum life if a principal is changing its own password.
> Right, LDAP password history is implemented in release 1.15 but not in 1.12.
> I guess you could print a kadmin ticket for the user from the KDB and then authenticate with it:
>
> kinit -k -c somefilename -t KDB: -S kadmin/admin username
> kadmin -c somefilename -q "cpw -pw password username"
> kinit -t KDB: support was added in release 1.9, so should be available.
But, since the user who ran the script files is wwwrun, I'm getting the following message:
$/usr/lib/mit/bin/kinit -k -c /home/wwwrun/arashimkrbcc -t KDB: -S kadmin/admin arashim
kinit: No such file or directory while setting up KDB keytab for realm TEST.COM
I've tried with several users and path locations for the cache credentials file but not succedeed. Using sudo before command works flawlessly.
What files or directories this command checks other than the cache credentials created, requiring to grant some permissions to the user who is running it?
According to kinit man, the "KDB:" option looks directly inside the Kerberos Database. So, this should be a permissions issue to access to the Kerberos Database. But honestly, I don't know what files and which should I grant to read to wwwrun to make this work avoiding to hardcode the root password in plain text. I'm not being able to track it on logs either.
Since we built the Kerberos Database on OpenLDAP krbContainer, what file is the one which non-root user should be able to read in order to make this work?
Another option regarding with the idea you sent me could be create a keytab owned by wwwrun to store all users keys and use. However I would prefer to ask the ticket looking directly into the KDB instead of using another keytab for all users. It could be a headache to maintain and totally a bad practice.
Again, thank you so much for your help.
Kind Regards.
Dario Garcia
Díaz-Miguel
GGCS-SES Unit
GGCS SKMF Infrastructure Division
GMV
C\ de Isaac Newton, 11
28760, Tres Cantos, Madrid
España
+34 918 07 21 00
+34 918 07 21 99
www.gmv.com
-----Mensaje original-----
De: Greg Hudson [mailto:ghu...@mit.edu]
Para: Dario García Díaz-Miguel <dgd...@gmv.com>; kerb...@mit.edu
Asunto: Re: cpw ignoring password policies
Asunto: Re: cpw ignoring password policies
Dario García Díaz-Miguel
Aug 14, 2020, 10:36:30 AM8/14/20
to Greg Hudson, kerb...@mit.edu
Hi again Greg,
Please forget my last email. I already found the files that wwwrun should be able to run. I will create a special group for reading the files inside /var/lib/kerberos/krb5kdc/
Now wwwrun acquires correctly the ticket.
Thank you so much.
Enviado el: viernes, 14 de agosto de 2020 9:12
Para: Greg Hudson <ghu...@mit.edu>; kerb...@mit.edu
Asunto: RE: cpw ignoring password policies
Please forget my last email. I already found the files that wwwrun should be able to run. I will create a special group for reading the files inside /var/lib/kerberos/krb5kdc/
Now wwwrun acquires correctly the ticket.
Thank you so much.
Kind Regards.
Dario Garcia
Díaz-Miguel
GGCS-SES Unit
GGCS SKMF Infrastructure Division
GMV
C\ de Isaac Newton, 11
28760, Tres Cantos, Madrid
España
+34 918 07 21 00
+34 918 07 21 99
www.gmv.com
-----Mensaje original-----
De: Dario García Díaz-Miguel
Dario Garcia
Díaz-Miguel
GGCS-SES Unit
GGCS SKMF Infrastructure Division
GMV
C\ de Isaac Newton, 11
28760, Tres Cantos, Madrid
España
+34 918 07 21 00
+34 918 07 21 99
www.gmv.com
-----Mensaje original-----
Enviado el: viernes, 14 de agosto de 2020 9:12
Para: Greg Hudson <ghu...@mit.edu>; kerb...@mit.edu
Asunto: RE: cpw ignoring password policies
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