RHEL 5 : pam_krb5 (RHSA-2010:0258)

This script is Copyright (C) 2010-2014 Tenable Network Security, Inc.


Synopsis :

The remote Red Hat host is missing a security update.

Description :

Updated pam_krb5 packages that fix one security issue and various bugs
are now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having low
security impact. A Common Vulnerability Scoring System (CVSS) base
score, which gives a detailed severity rating, is available from the
CVE link in the References section.

The pam_krb5 module allows Pluggable Authentication Modules (PAM)
aware applications to use Kerberos to verify user identities by
obtaining user credentials at log in time.

A flaw was found in pam_krb5. In some non-default configurations
(specifically, those where pam_krb5 would be the first module to
prompt for a password), the text of the password prompt varied based
on whether or not the username provided was a username known to the
system. A remote attacker could use this flaw to recognize valid
usernames, which would aid a dictionary-based password guess attack.
(CVE-2009-1384)

This update also fixes the following bugs :

* certain applications which do not properly implement PAM
conversations may fail to authenticate users whose passwords have
expired and must be changed, or may succeed without forcing the user's
password to be changed. This bug is triggered by a previously-applied
fix to pam_krb5 which makes it comply more closely to PAM
specifications. If an application misbehaves, enabling the
'chpw_prompt' option for its service should restore the old behavior.
(BZ#509092)

* pam_krb5 does not allow the user to change an expired password in
cases where the Key Distribution Center (KDC) is configured to refuse
attempts to obtain forwardable password-changing credentials. This
update fixes this issue. (BZ#489015)

* failure to verify TGT because of wrong keytab handling. (BZ#450776)

Users of pam_krb5 are advised to upgrade to these updated packages,
which resolve these issues.

See also :

https://www.redhat.com/security/data/cve/CVE-2009-1384.html
http://rhn.redhat.com/errata/RHSA-2010-0258.html

Solution :

Update the affected pam_krb5 package.

Risk factor :

Medium / CVSS Base Score : 5.0
(CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N)
CVSS Temporal Score : 4.1
(CVSS2#E:F/RL:OF/RC:C)
Public Exploit Available : true

Family: Red Hat Local Security Checks

Nessus Plugin ID: 46287 ()

Bugtraq ID: 35112

CVE ID: CVE-2009-1384