A keytab file stores Kerberos keys for computer and service accounts. Safeguard Authentication Services automatically generates and maintains keytab files when you join the Active Directory domain or when you create service accounts in Active Directory. By default, the keytab files are created in /etc/opt/quest/vas directory. Each keytab file is named according to the service that uses it.

For example, the host principal keys are stored in the /etc/opt/quest/vas/host.keytab file. Keytab files are stored using the standard MIT style and may be used by third-party applications.

The keytab is essentially the computer's Active Directory password. It is owned by root and must be secured accordingly. The default permissions for a computer object restrict the computer from accessing and modifying sensitive data in Active Directory. The schema extensions are carefully designed to allow computers with default permissions to access only the Unix account data that is absolutely necessary for the normal operation of Safeguard Authentication Services.

One Identity recommends that administrators not modify the default permissions for the computer object to make them either more or less restrictive. Changing the computer object permissions could disrupt normal operation or create a security liability in Active Directory if a Unix host is compromised.

If the host.keytab file is compromised by unauthorized root access on the Unix system, then you can assume the password for the associated computer object is compromised as well. You can reset the computer object's password and generate a new keytab file by running

vastool  -u <admin> passwd –r –k /etc/opt/quest/vas/host.keytab host/

Another option is to delete the computer object and recreate it by running vastool create host/.