Active Directory

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SSL connection error For Delinea MFA with DirectControl 

Muco of the Troubleshooting comes from the Knowledgebase Article is derived from KB-8958: MFA with DirectControl fails with SSL connection error and Preparing a Linux Client Server for Centrify and 2FA for CentOS-7

Problem :

When attempting to log in with a user that requires MFA the following error is presented:

$ ssh user@192.168.0.1
SSL Connection Error

Cause:

The error is likely due to a certificate problem. A required certificate may be missing or the permission may not be set correctly

How to check:

# /usr/share/centrifydc/bin/adcdiag
VERSION   : Verify that DirectControl version supports MFA               : Pass
JOINSTATE : Verify that DirectControl is in connected mode               : Pass
ZONECHK   : Verify that MFA is supported in the zone                     : Pass
SSHDCFG   : Verify that SSHD enables ChallengeResponseAuthentication     : Warning
          : Cannot read sshd configuration file. Probably you are not
          : using Delinea openssh. SSH login for MFA users will fail if
          : option ChallengeResponseAuthentication is not set to yes.
          : Please check and ensure ChallengeResponseAuthentication is
          : set to yes in sshd configuration file.
CDCCFG    : Verify that MFA options in centrifydc.conf are correct       : Pass
PROXYCFG  : Verify that HTTP proxy configuration is set properly         : Pass
CLDINST   : Verify that trusted Identity Platform instance is specified  : Pass
          : Successfully connected to Identity Platform and certificate
          : has been verified OK.
CNTRCFG   : Verify that Connectors are configured correctly              : Pass
CURCNTR   : Verify that DirectControl has selected a workable Connector  : Pass
CLOUDROLE : Verify that this machine has permissions to perform Identity
          : Platform authentication                                      : Pass
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Check the Logs at /var/centrify/tmp…. You may notice some errors like 

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ERROR:
Not a trusted connector or no valid connector certificate installed locally.
SUGGESTIONS:
1. Verify that the IWA root CA certificate is installed in the system. Please refer to KB-7393 on how to configure the root CA certificate in the system.
2. Please collect connector log if you need Delinea support.
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Resolution:

Check whether the Certificates have been added at

  •  /etc/pki/ca-trust/source/anchors/ 
  • /var/centrify/net/certs

Check the SSH Settings at

# vim /etc/ssh/sshd_config
# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
#PermitEmptyPasswords no
PasswordAuthentication no


# Change to no to disable s/key passwords
#ChallengeResponseAuthentication yes
ChallengeResponseAuthentication yes

Restart the SSHD Services

# systemctl restart sshd.service

Restart the Centrifydc services

# /usr/share/centrifydc/bin/centrifydc restart

Active Directory Flush and Reload

# adflush -f
# adreload
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Restricting SSH Access when using Centrify-Free

To restrict users from accessing the system using Centrify free can be easily managed by using the following files

/etc/centrifydc/users.allow
/etc/centrifydc/groups.allow
/etc/centrifydc/users.deny
/etc/centrifydc/groups.deny

1. You have to manually create the the files accordingly and place it at /etc/centifydc. Next you have to  line 273 and uncomment the line

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pam.allow.users: file:/etc/centrifydc/users.allow
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If you are blocking by groups, you can likewise uncomment the

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pam.allow.groups: file:/etc/centrifydc/groups.allow
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2. Flush and Reload Centrify-Free

# adflush
# adreload

3. Add users you wish to have access into the system into /etc/centrifydc/users.allow