Oh, this requires the pam_krb5 package :P


From: Aaron Hicks <aaron.hicks@nesi.org.nz>
Sent: Tuesday, November 28, 2017 2:28:15 PM
To: 'FreeIPA users list'
Cc: 'Sumit Bose'
Subject: RE: [Freeipa-users] Re: Expired passwords and generating an OTP token
 

Hello the List,

 

We have a workaround, but it is not entirely satisfactory, we change /etc/pam.d/password-auth-ac

 

password    requisite     pam_pwquality.so try_first_pass local_users_only retry=3 authtok_type=

password    sufficient    pam_unix.so sha512 shadow try_first_pass use_authtok

#password    sufficient    pam_sss.so use_authtok

password    sufficient    pam_krb5.so chpw_prompt=true use_authok # fix for password reset

 

This allows a user to reset a password if expired, but gives them shell rather than disconnecting. New ssh connections now require 2FA.

 

Weíre now quite certain itís a bug in sssd & pam_sss

 

Regards,

 

Aaron

 

 

From: Aaron Hicks [mailto:aaron.hicks@nesi.org.nz]
Sent: Friday, 24 November 2017 4:57 PM
To: 'FreeIPA users list' <freeipa-users@lists.fedorahosted.org>
Cc: 'Sumit Bose' <sbose@redhat.com>
Subject: RE: [Freeipa-users] Re: Expired passwords and generating an OTP token

 

Hello the list,

 

Itís here: https://pagure.io/SSSD/sssd/blob/master/f/src/providers/ipa/ipa_auth.c#_395

 

SSSD is not doing its job properly when a user has an expired password and an OTP token, and they should reset their password at the ssh prompt.

 

When a user has an expired password it should ignore the OTP token during password reset process, and then disconnect.

 

The condition where an expired or compromised temporary password is obtained by an unauthorised entity means that as long as the unauthorised entity does not have the OTP token secret, the worst they can do is reset your password. This condition is escaped when someone, either the user, a helpdesk agent, or an admin, resets the password to something the unauthorised entity doesnít know.

 

The case of the unauthorised entity having both the password and OTP token is already recognised as a compromised state, so the code doesnít need to protect us from that.

 

Regards,

 

Aaron

 

From: Aaron Hicks [mailto:aaron.hicks@nesi.org.nz]
Sent: Thursday, 23 November 2017 5:44 PM
To: 'FreeIPA users list' <freeipa-users@lists.fedorahosted.org>
Cc: 'Sumit Bose' <sbose@redhat.com>
Subject: Re: [Freeipa-users] Re: Expired passwords and generating an OTP token

 

Progress,

 

We made Pam use kinit username when a user had an expired password, and this allowed users to reset passwords at the ssh prompt.

 

However passwd remains broken on all the hosts, regardless of their auth indicator.

 

Aaron

 

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From: Aaron Hicks <aaron.hicks@nesi.org.nz>
Sent: Thursday, November 23, 2017 4:25:12 PM
To: 'FreeIPA users list'
Cc: 'Sumit Bose'
Subject: RE: [Freeipa-users] Re: Expired passwords and generating an OTP token

 

Hello the list,

 

The next bit of information is that the passwd command itself is broken when a user has a OTP token set.

 

$ passwd

Changing password for user otpuser1.

Current Password:

passwd: Authentication token manipulation error

$ passwd

Changing password for user otpuser1.

Current Password:

passwd: Authentication token manipulation error

$ passwd

Changing password for user otpuser1.

Current Password:

passwd: Authentication token manipulation error

$ passwd

Changing password for user otpuser1.

Current Password:

passwd: Authentication token manipulation error

 

These were with the userís valid-not-expired password, and with passwordOTPCODE

 

The Current Password: prompt fails.

 

 

Regards,

 

Aaron

 

 

From: Aaron Hicks [mailto:aaron.hicks@nesi.org.nz]
Sent: Thursday, 23 November 2017 3:44 PM
To: 'FreeIPA users list' <freeipa-users@lists.fedorahosted.org>
Cc: 'Sumit Bose' <sbose@redhat.com>
Subject: RE: [Freeipa-users] Re: Expired passwords and generating an OTP token

 

Hello the list,

 

Weíve kept at this today and this is what we think we are seeing:

 

  • Preauth is detecting that a user has an expired password and a token, so discards the token and just asks for password
  • Password check succeeds and hands to the password change process (maybe using /etc/pam.d/passwd and /etc/pam.d/system-auth)
  • BUT the Current Password: check fails because it doesnít preauth to check if the password is expired
  • AND because the password is expired passwordOTPCODE is not valid either

 

Similarly, accounts with expired passwords canít authenticate against the API because their password is expired. Which would at least allow our customer management system to disable or delete their OTP token so they can reset their passwords.

 

In addition to this, users are not able to reset passwords at the ssh login on hosts where 2FA is not enabled either! So this seems to be narrowing down on the bits of pam and sssd uset to authenticate the password change process.

 

An interesting note is, kinit does not require OTPCODE.

 

Finally, no users do not have access to the FreeIPA web interface or a host without 2FA. The 2FA secured host is to be their lander node into our network.

 

Regards,

 

Aaron

From: Aaron Hicks [mailto:aaron.hicks@nesi.org.nz]
Sent: Thursday, 23 November 2017 10:33 AM
To: 'FreeIPA users list' <freeipa-users@lists.fedorahosted.org>
Cc: 'Sumit Bose' <sbose@redhat.com>
Subject: RE: [Freeipa-users] Re: Expired passwords and generating an OTP token

 

Hello the List,

 

A couple of new things to this problem, when a user has an expired password and a valid OTP token, the password reset process is broken on all machines at the ssh prompt. Even the ones that do not require 2FA.

 

Feedback so far form Sumit indicates this is incorrect behaviour.

 

As an attempt to get around this, Iíve tried adding a permission to the helpdesk role that would allow them to manage OTP tokens. Iíll submit another thread on that.

 

Regards,

 

Aaron

 

From: Aaron Hicks [mailto:aaron.hicks@nesi.org.nz]
Sent: Thursday, 23 November 2017 6:31 AM
To: Sumit Bose <sbose@redhat.com>
Cc: 'FreeIPA users list' <freeipa-users@lists.fedorahosted.org>; 'Sumit Bose' <sbose@redhat.com>
Subject: Re: [Freeipa-users] Re: Expired passwords and generating an OTP token

 

Hi Sumit,

 

I sent those to you directly as I wasnít comfortable posting them to the list.

 

Regards,

 

Aaron

 


From: Sumit Bose <sbose@redhat.com>
Sent: Wednesday, November 22, 2017 10:19:34 PM
To: Aaron Hicks
Cc: 'FreeIPA users list'; 'Sumit Bose'
Subject: Re: [Freeipa-users] Re: Expired passwords and generating an OTP token

 

On Wed, Nov 22, 2017 at 09:21:52PM +1300, Aaron Hicks wrote:
> Hi Sumit,
>
> Here is /etc/pam.d/password-auth I missed that it was an include, an that you wanted it too, again it's as installed bt CentOS 7.4 and ipa-client-install
>

ok, the PAM configuration looks good. Can you send me the PAM related
messages form /var/log/secure or the journal which cover the failed
attempt? And additionally the SSSD logs with debug_level=9 from the same
time. Most important would be sssd_pam.log, sssd_domain.name.log and
krb5_child-log.

bye,
Sumit