The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.9 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a malformed request packet that does not trigger a response packet.

The remote host is affected by the vulnerability described in GLSA-201201-13 (MIT Kerberos 5: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in MIT Kerberos 5. Please       review the CVE identifiers referenced below for details.
  Impact :

    A remote attacker may be able to execute arbitrary code with the       privileges of the administration daemon or the Key Distribution Center       (KDC) daemon, cause a Denial of Service condition, or possibly obtain       sensitive information. Furthermore, a remote attacker may be able to       spoof Kerberos authorization, modify KDC responses, forge user data       messages, forge tokens, forge signatures, impersonate a client, modify       user-visible prompt text, or have other unspecified impact.
  Workaround :

    There is no known workaround at this time.

An advisory published by the MIT Kerberos team says :

The MIT krb5 Key Distribution Center (KDC) daemon is vulnerable to denial of service attacks from unauthenticated remote attackers.
CVE-2011-0281 and CVE-2011-0282 occur only in KDCs using LDAP back ends, but CVE-2011-0283 occurs in all krb5-1.9 KDCs.

Exploit code is not known to exist, but the vulnerabilities are easy to trigger manually. The trigger for CVE-2011-0281 has already been disclosed publicly, but that fact might not be obvious to casual readers of the message in which it was disclosed. The triggers for CVE-2011-0282 and CVE-2011-0283 have not yet been disclosed publicly, but they are also trivial.

CVE-2011-0281: An unauthenticated remote attacker can cause a KDC configured with an LDAP back end to become completely unresponsive until restarted.

CVE-2011-0282: An unauthenticated remote attacker can cause a KDC configured with an LDAP back end to crash with a NULL pointer dereference.

CVE-2011-0283: An unauthenticated remote attacker can cause a krb5-1.9 KDC with any back end to crash with a NULL pointer dereference.

Updated krb5 packages that fix two security issues are now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having important security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

Kerberos is a network authentication system which allows clients and servers to authenticate to each other using symmetric encryption and a trusted third-party, the Key Distribution Center (KDC).

A NULL pointer dereference flaw was found in the way the MIT Kerberos KDC processed principal names that were not null terminated, when the KDC was configured to use an LDAP back end. A remote attacker could use this flaw to crash the KDC via a specially crafted request.
(CVE-2011-0282)

A denial of service flaw was found in the way the MIT Kerberos KDC processed certain principal names when the KDC was configured to use an LDAP back end. A remote attacker could use this flaw to cause the KDC to hang via a specially crafted request. (CVE-2011-0281)

Red Hat would like to thank the MIT Kerberos Team for reporting these issues. Upstream acknowledges Kevin Longfellow of Oracle Corporation as the original reporter of the CVE-2011-0281 issue.

All krb5 users should upgrade to these updated packages, which contain a backported patch to correct these issues. After installing the updated packages, the krb5kdc daemon will be restarted automatically.

Updated krb5 packages that fix three security issues are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having important security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

Kerberos is a network authentication system which allows clients and servers to authenticate to each other using symmetric encryption and a trusted third-party, the Key Distribution Center (KDC).

A NULL pointer dereference flaw was found in the way the MIT Kerberos KDC processed principal names that were not null terminated, when the KDC was configured to use an LDAP back end. A remote attacker could use this flaw to crash the KDC via a specially crafted request.
(CVE-2011-0282)

A denial of service flaw was found in the way the MIT Kerberos KDC processed certain principal names when the KDC was configured to use an LDAP back end. A remote attacker could use this flaw to cause the KDC to hang via a specially crafted request. (CVE-2011-0281)

A denial of service flaw was found in the way the MIT Kerberos V5 slave KDC update server (kpropd) processed certain update requests for KDC database propagation. A remote attacker could use this flaw to terminate the kpropd daemon via a specially crafted update request.
(CVE-2010-4022)

Red Hat would like to thank the MIT Kerberos Team for reporting the CVE-2011-0282 and CVE-2011-0281 issues. Upstream acknowledges Kevin Longfellow of Oracle Corporation as the original reporter of the CVE-2011-0281 issue.

All krb5 users should upgrade to these updated packages, which contain backported patches to correct these issues. After installing the updated packages, the krb5kdc daemon will be restarted automatically.

ID	Name	Product	Family	Severity
57655	GLSA-201201-13 : MIT Kerberos 5: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	medium
53440	FreeBSD : krb5 -- MITKRB5-SA-2011-002, KDC vulnerable to hang when using LDAP back end (4ab413ea-66ce-11e0-bf05-d445f3aa24f0)	Nessus	FreeBSD Local Security Checks	medium
53418	CentOS 5 : krb5 (CESA-2011:0199)	Nessus	CentOS Local Security Checks	medium
51918	RHEL 6 : krb5 (RHSA-2011:0200)	Nessus	Red Hat Local Security Checks	medium
51917	RHEL 5 : krb5 (RHSA-2011:0199)	Nessus	Red Hat Local Security Checks	medium

Detections

Analytics

CVE-2011-0283

high

Tenable Plugins

medium

medium

medium

medium

medium