The do_standalone function in the MIT krb5 KDC database propagation daemon (kpropd) in Kerberos 1.7, 1.8, and 1.9, when running in standalone mode, does not properly handle when a worker child process "exits abnormally," which allows remote attackers to cause a denial of service (listening process termination, no new connections, and lack of updates in slave KVC) via unspecified vectors.

Multiple KDC DoS vulnerabilities if used with LDAP backends have been fixed in krb5. CVE-2011-0281 and CVE-2011-0282 have been assigned.
Additionally a DoS vulnerability in kpropd has been fixed.
CVE-2010-4022 has been assigned to this issue.

The remote Oracle Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2011-0200 advisory.

    - add upstream patches to fix standalone kpropd exiting if the per-client       child process exits with an error, and hang or crash in the KDC when using       the LDAP kdb backend (CVE-2010-4022, CVE-2011-0281, CVE-2011-0282, #671101)
    - incorporate candidate patch to fix various issues from MITKRB5-SA-2010-007       (CVE-2010-1323, CVE-2010-1324, CVE-2010-4020, #651962)

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

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 KDC database propagation daemon (kpropd) is vulnerable to a denial-of-service attack triggered by invalid network input. If a kpropd worker process receives invalid input that causes it to exit with an abnormal status, it can cause the termination of the listening process that spawned it, preventing the slave KDC it was running on from receiving database updates from the master KDC.

Exploit code is not known to exist, but the vulnerabilities are easy to trigger manually.

An unauthenticated remote attacker can cause kpropd running in standalone mode (the '-S' option) to terminate its listening process, preventing database propagations to the KDC host on which it was running. Configurations where kpropd runs in incremental propagation mode ('iprop') or as an inetd server are not affected.

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.

This update incorporates fixes from upstream advisories MITKRB5-SA-2011-001 (standalone kpropd exits if a per-client child exits with an error) and MITKRB5-SA-2011-002 (uninitialized pointer crash in the KDC, hang or crash in the KDC with the LDAP backend).

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Keiichi Mori discovered that the MIT krb5 KDC database propagation daemon (kpropd) is vulnerable to a denial of service attack due to improper logic when a worker child process exited because of invalid network input. This could only occur when kpropd is running in standalone mode; kpropd was not affected when running in incremental propagation mode ('iprop') or as an inetd server. This issue only affects Ubuntu 9.10, Ubuntu 10.04 LTS, and Ubuntu 10.10.
(CVE-2010-4022)

Kevin Longfellow and others discovered that the MIT krb5 Key Distribution Center (KDC) daemon is vulnerable to denial of service attacks when using an LDAP back end due to improper handling of network input. (CVE-2011-0281, CVE-2011-0282).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Multiple vulnerabilities were discovered and corrected in krb5 :

The MIT krb5 KDC database propagation daemon (kpropd) is vulnerable to a denial-of-service attack triggered by invalid network input. If a kpropd worker process receives invalid input that causes it to exit with an abnormal status, it can cause the termination of the listening process that spawned it, preventing the slave KDC it was running on From receiving database updates from the master KDC (CVE-2010-4022).

The MIT krb5 Key Distribution Center (KDC) daemon is vulnerable to denial of service attacks from unauthenticated remote attackers (CVE-2011-0281, CVE-2011-0282).

The updated packages have been patched to correct this issue.

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
75560	openSUSE Security Update : krb5 (openSUSE-SU-2011:0111-1)	Nessus	SuSE Local Security Checks	medium
68196	Oracle Linux 6 : krb5 (ELSA-2011-0200)	Nessus	Oracle Linux Local Security Checks	medium
57655	GLSA-201201-13 : MIT Kerberos 5: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	medium
53743	openSUSE Security Update : krb5 (openSUSE-SU-2011:0111-1)	Nessus	SuSE Local Security Checks	medium
53441	FreeBSD : krb5 -- MITKRB5-SA-2011-001, kpropd denial of service (64f24a1e-66cf-11e0-9deb-f345f3aa24f0)	Nessus	FreeBSD Local Security Checks	medium
53418	CentOS 5 : krb5 (CESA-2011:0199)	Nessus	CentOS Local Security Checks	medium
52019	Fedora 14 : krb5-1.8.2-8.fc14 (2011-1225)	Nessus	Fedora Local Security Checks	medium
52017	Fedora 13 : krb5-1.7.1-17.fc13 (2011-1210)	Nessus	Fedora Local Security Checks	medium
51985	Ubuntu 8.04 LTS / 9.10 / 10.04 LTS / 10.10 : krb5 vulnerabilities (USN-1062-1)	Nessus	Ubuntu Local Security Checks	medium
51932	Mandriva Linux Security Advisory : krb5 (MDVSA-2011:025)	Nessus	Mandriva 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

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CVE-2010-4022

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