error reading keytab file krb5.keytab
- by Banjer
I've noticed these kerberos keytab error messages on both SLES 11.2 and CentOS 6.3:
sshd[31442]: pam_krb5[31442]: error reading keytab 'FILE: / etc/ krb5. keytab'
/etc/krb5.keytab does not exist on our hosts, and from what I understand of the keytab file, we don't need it. Per this kerberos keytab introduction:
A keytab is a file containing pairs of Kerberos principals and
encrypted keys (these are derived from the Kerberos password). You can
use this file to log into Kerberos without being prompted for a
password. The most common personal use of keytab files is to allow
scripts to authenticate to Kerberos without human interaction, or
store a password in a plaintext file.
This sounds like something we do not need and is perhaps better security-wise to not have it.
How can I keep this error from popping up in our system logs? Here is my krb5.conf if its useful:
banjer@myhost:~> cat /etc/krb5.conf
# This file managed by Puppet
#
[libdefaults]
default_tkt_enctypes = RC4-HMAC DES-CBC-MD5 DES-CBC-CRC
default_tgs_enctypes = RC4-HMAC DES-CBC-MD5 DES-CBC-CRC
preferred_enctypes = RC4-HMAC DES-CBC-MD5 DES-CBC-CRC
default_realm = FOO.EXAMPLE.COM
dns_lookup_kdc = true
clockskew = 300
[logging]
default = SYSLOG:NOTICE:DAEMON
kdc = FILE:/var/log/kdc.log
kadmind = FILE:/var/log/kadmind.log
[appdefaults]
pam = {
ticket_lifetime = 1d
renew_lifetime = 1d
forwardable = true
proxiable = false
retain_after_close = false
minimum_uid = 0
debug = false
banner = "Enter your current"
}
Let me know if you need to see any other configs. Thanks.
EDIT
This message shows up in /var/log/secure whenever a non-root user logs in via SSH or the console. It seems to only occur with password-based authentication. If I do a key-based ssh to a server, I don't see the error. If I log in with root, I do not see the error. Our Linux servers authenticate against Active Directory, so its a hearty mix of PAM, samba, kerberos, and winbind that is used to authenticate a user.
