An unspecified third-party database module for the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.10.x allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted request, a different vulnerability than CVE-2013-1418.

The remote OracleVM system is missing necessary patches to address critical security updates :

  - actually apply that last patch

  - incorporate fix for MITKRB5-SA-2014-001 (CVE-2014-4345,     #1128157)

  - ksu: when evaluating .k5users, don't throw away data     from .k5users when we're not passed a command to run,     which implicitly means we're attempting to run the     target user's shell (#1026721, revised)

  - ksu: when evaluating .k5users, treat lines with just a     principal name as if they contained the principal name     followed by '*', and don't throw away data from .k5users     when we're not passed a command to run, which implicitly     means we're attempting to run the target user's shell     (#1026721, revised)

  - gssapi: pull in upstream fix for a possible NULL     dereference in spnego (CVE-2014-4344, #1121510)

  - gssapi: pull in proposed-and-accepted fix for a double     free in initiators (David Woodhouse, CVE-2014-4343,     #1121510)

  - correct a type mistake in the backported fix for     (CVE-2013-1418, CVE-2013-6800)

  - pull in backported fix for denial of service by     injection of malformed GSSAPI tokens (CVE-2014-4341,     CVE-2014-4342, #1121510)

  - incorporate backported patch for remote crash of KDCs     which serve multiple realms simultaneously (RT#7756,     CVE-2013-1418/CVE-2013-6800, more of

  - pull in backport of patch to not subsequently always     require that responses come from master KDCs if we get     one from a master somewhere along the way while chasing     referrals (RT#7650, #1113652)

  - ksu: if the -e flag isn't used, use the target user's     shell when checking for authorization via the target     user's .k5users file (#1026721)

  - define _GNU_SOURCE in files where we use EAI_NODATA, to     make sure that it's declared (#1059730)

  - spnego: pull in patch from master to restore preserving     the OID of the mechanism the initiator requested when we     have multiple OIDs for the same mechanism, so that we     reply using the same mechanism OID and the initiator     doesn't get confused (#1087068, RT#7858)

  - add patch from Jatin Nansi to avoid attempting to clear     memory at the NULL address if krb5_encrypt_helper     returns an error when called from encrypt_credencpart     (#1055329, pull #158)

  - drop patch to add additional access checks to ksu - they     shouldn't be resulting in any benefit

  - apply patch from Nikolai Kondrashov to pass a default     realm set in /etc/sysconfig/krb5kdc to the     kdb_check_weak helper, so that it doesn't produce an     error if there isn't one set in krb5.conf (#1009389)

  - packaging: don't Obsoletes: older versions of     krb5-pkinit-openssl and virtual Provide:
    krb5-pkinit-openssl on EL6, where we don't need to     bother with any of that (#1001961)

  - pkinit: backport tweaks to avoid trying to call the     prompter callback when one isn't set (part of #965721)

  - pkinit: backport the ability to use a prompter callback     to prompt for a password when reading private keys (the     rest of #965721)

  - backport fix to not spin on a short read when reading     the length of a response over TCP (RT#7508, #922884)

  - backport fix for trying all compatible keys when not     being strict about acceptor names while reading AP-REQs     (RT#7883, #1070244)

  - backport fix for not being able to verify the list of     transited realms in GSS acceptors (RT#7639, #959685)

  - pull fix for keeping track of the message type when     parsing FAST requests in the KDC (RT#7605, #951965)

  - incorporate upstream patch to fix a NULL pointer     dereference while processing certain TGS requests     (CVE-2013-1416, #950343)

  - incorporate upstream patch to fix a NULL pointer     dereference when the client supplies an     otherwise-normal-looking PKINIT request (CVE-2013-1415,     #917910)

  - add patch to avoid dereferencing a NULL pointer in the     KDC when handling a draft9 PKINIT request (#917910,     CVE-2012-1016)

  - pull up fix for UDP ping-pong flaw in kpasswd service     (CVE-2002-2443, 

  - don't leak the memory used to hold the previous entry     when walking a keytab to figure out which kinds of keys     we have (#911147)

It was found that if a KDC served multiple realms, certain requests could cause the setup_server_realm() function to dereference a NULL pointer. A remote, unauthenticated attacker could use this flaw to crash the KDC using a specially crafted request. (CVE-2013-1418 , CVE-2013-6800)

A NULL pointer dereference flaw was found in the MIT Kerberos SPNEGO acceptor for continuation tokens. A remote, unauthenticated attacker could use this flaw to crash a GSSAPI-enabled server application.
(CVE-2014-4344)

A buffer overflow was found in the KADM5 administration server (kadmind) when it was used with an LDAP back end for the KDC database.
A remote, authenticated attacker could potentially use this flaw to execute arbitrary code on the system running kadmind. (CVE-2014-4345)

Two buffer over-read flaws were found in the way MIT Kerberos handled certain requests. A remote, unauthenticated attacker who is able to inject packets into a client or server application's GSSAPI session could use either of these flaws to crash the application.
(CVE-2014-4341 , CVE-2014-4342)

A double-free flaw was found in the MIT Kerberos SPNEGO initiators. An attacker able to spoof packets to appear as though they are from an GSSAPI acceptor could use this flaw to crash a client application that uses MIT Kerberos. (CVE-2014-4343)

Updated krb5 packages that fix multiple security issues and several bugs are now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having Moderate 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 networked authentication system which allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos KDC.

It was found that if a KDC served multiple realms, certain requests could cause the setup_server_realm() function to dereference a NULL pointer. A remote, unauthenticated attacker could use this flaw to crash the KDC using a specially crafted request. (CVE-2013-1418, CVE-2013-6800)

A NULL pointer dereference flaw was found in the MIT Kerberos SPNEGO acceptor for continuation tokens. A remote, unauthenticated attacker could use this flaw to crash a GSSAPI-enabled server application.
(CVE-2014-4344)

A buffer overflow was found in the KADM5 administration server (kadmind) when it was used with an LDAP back end for the KDC database.
A remote, authenticated attacker could potentially use this flaw to execute arbitrary code on the system running kadmind. (CVE-2014-4345)

Two buffer over-read flaws were found in the way MIT Kerberos handled certain requests. A remote, unauthenticated attacker who is able to inject packets into a client or server application's GSSAPI session could use either of these flaws to crash the application.
(CVE-2014-4341, CVE-2014-4342)

A double-free flaw was found in the MIT Kerberos SPNEGO initiators. An attacker able to spoof packets to appear as though they are from an GSSAPI acceptor could use this flaw to crash a client application that uses MIT Kerberos. (CVE-2014-4343)

These updated krb5 packages also include several bug fixes. Space precludes documenting all of these changes in this advisory. Users are directed to the Red Hat Enterprise Linux 6.6 Technical Notes, linked to in the References section, for information on the most significant of these changes.

All krb5 users are advised to upgrade to these updated packages, which contain backported patches to correct these issues.

It was found that if a KDC served multiple realms, certain requests could cause the setup_server_realm() function to dereference a NULL pointer. A remote, unauthenticated attacker could use this flaw to crash the KDC using a specially crafted request. (CVE-2013-1418, CVE-2013-6800)

A NULL pointer dereference flaw was found in the MIT Kerberos SPNEGO acceptor for continuation tokens. A remote, unauthenticated attacker could use this flaw to crash a GSSAPI-enabled server application.
(CVE-2014-4344)

A buffer overflow was found in the KADM5 administration server (kadmind) when it was used with an LDAP back end for the KDC database.
A remote, authenticated attacker could potentially use this flaw to execute arbitrary code on the system running kadmind. (CVE-2014-4345)

Two buffer over-read flaws were found in the way MIT Kerberos handled certain requests. A remote, unauthenticated attacker who is able to inject packets into a client or server application's GSSAPI session could use either of these flaws to crash the application.
(CVE-2014-4341, CVE-2014-4342)

A double-free flaw was found in the MIT Kerberos SPNEGO initiators. An attacker able to spoof packets to appear as though they are from an GSSAPI acceptor could use this flaw to crash a client application that uses MIT Kerberos. (CVE-2014-4343)

The remote Oracle Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2014-1389 advisory.

    - incorporate fix for MITKRB5-SA-2014-001 (CVE-2014-4345, #1128157)
    - gssapi: pull in upstream fix for a possible NULL dereference in spnego       (CVE-2014-4344, #1121510)
    - gssapi: pull in proposed-and-accepted fix for a double free in initiators       (David Woodhouse, CVE-2014-4343, #1121510)
    - correct a type mistake in the backported fix for CVE-2013-1418/CVE-2013-6800
    - pull in backported fix for denial of service by injection of malformed       GSSAPI tokens (CVE-2014-4341, CVE-2014-4342, #1121510)
    - incorporate backported patch for remote crash of KDCs which serve multiple       realms simultaneously (RT#7756, CVE-2013-1418/CVE-2013-6800, more of

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.

It was found that if a KDC served multiple realms, certain requests could cause the setup_server_realm() function to dereference a NULL pointer. A remote, unauthenticated attacker could use this flaw to crash the KDC using a specially crafted request. (CVE-2013-1418, CVE-2013-6800)

A NULL pointer dereference flaw was found in the MIT Kerberos SPNEGO acceptor for continuation tokens. A remote, unauthenticated attacker could use this flaw to crash a GSSAPI-enabled server application.
(CVE-2014-4344)

A buffer over-read flaw was found in the way MIT Kerberos handled certain requests. A man-in-the-middle attacker with a valid Kerberos ticket who is able to inject packets into a client or server application's GSSAPI session could use this flaw to crash the application. (CVE-2014-4341)

This update also fixes the following bugs :

  - Prior to this update, the libkrb5 library occasionally     attempted to free already freed memory when encrypting     credentials. As a consequence, the calling process     terminated unexpectedly with a segmentation fault. With     this update, libkrb5 frees memory correctly, which     allows the credentials to be encrypted appropriately and     thus prevents the mentioned crash.

  - Previously, when the krb5 client library was waiting for     a response from a server, the timeout variable in     certain cases became a negative number. Consequently,     the client could enter a loop while checking for     responses. With this update, the client logic has been     modified and the described error no longer occurs.

After installing the updated packages, the krb5kdc daemon will be restarted automatically.

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

Red Hat Product Security has rated this update as having Moderate 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 an authentication system which allows clients and services to authenticate to each other with the help of a trusted third party, a Kerberos Key Distribution Center (KDC).

It was found that if a KDC served multiple realms, certain requests could cause the setup_server_realm() function to dereference a NULL pointer. A remote, unauthenticated attacker could use this flaw to crash the KDC using a specially crafted request. (CVE-2013-1418, CVE-2013-6800)

A NULL pointer dereference flaw was found in the MIT Kerberos SPNEGO acceptor for continuation tokens. A remote, unauthenticated attacker could use this flaw to crash a GSSAPI-enabled server application.
(CVE-2014-4344)

A buffer over-read flaw was found in the way MIT Kerberos handled certain requests. A man-in-the-middle attacker with a valid Kerberos ticket who is able to inject packets into a client or server application's GSSAPI session could use this flaw to crash the application. (CVE-2014-4341)

This update also fixes the following bugs :

* Prior to this update, the libkrb5 library occasionally attempted to free already freed memory when encrypting credentials. As a consequence, the calling process terminated unexpectedly with a segmentation fault. With this update, libkrb5 frees memory correctly, which allows the credentials to be encrypted appropriately and thus prevents the mentioned crash. (BZ#1004632)

* Previously, when the krb5 client library was waiting for a response from a server, the timeout variable in certain cases became a negative number. Consequently, the client could enter a loop while checking for responses. With this update, the client logic has been modified and the described error no longer occurs. (BZ#1089732)

All krb5 users are advised to 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.

From Red Hat Security Advisory 2014:1245 :

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

Red Hat Product Security has rated this update as having Moderate 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 an authentication system which allows clients and services to authenticate to each other with the help of a trusted third party, a Kerberos Key Distribution Center (KDC).

It was found that if a KDC served multiple realms, certain requests could cause the setup_server_realm() function to dereference a NULL pointer. A remote, unauthenticated attacker could use this flaw to crash the KDC using a specially crafted request. (CVE-2013-1418, CVE-2013-6800)

A NULL pointer dereference flaw was found in the MIT Kerberos SPNEGO acceptor for continuation tokens. A remote, unauthenticated attacker could use this flaw to crash a GSSAPI-enabled server application.
(CVE-2014-4344)

A buffer over-read flaw was found in the way MIT Kerberos handled certain requests. A man-in-the-middle attacker with a valid Kerberos ticket who is able to inject packets into a client or server application's GSSAPI session could use this flaw to crash the application. (CVE-2014-4341)

This update also fixes the following bugs :

* Prior to this update, the libkrb5 library occasionally attempted to free already freed memory when encrypting credentials. As a consequence, the calling process terminated unexpectedly with a segmentation fault. With this update, libkrb5 frees memory correctly, which allows the credentials to be encrypted appropriately and thus prevents the mentioned crash. (BZ#1004632)

* Previously, when the krb5 client library was waiting for a response from a server, the timeout variable in certain cases became a negative number. Consequently, the client could enter a loop while checking for responses. With this update, the client logic has been modified and the described error no longer occurs. (BZ#1089732)

All krb5 users are advised to 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.

The remote Ubuntu 14.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-2310-1 advisory.

    It was discovered that Kerberos incorrectly handled certain crafted Draft 9 requests. A remote attacker     could use this issue to cause the daemon to crash, resulting in a denial of service. This issue only     affected Ubuntu 12.04 LTS. (CVE-2012-1016)

    It was discovered that Kerberos incorrectly handled certain malformed KRB5_PADATA_PK_AS_REQ AS-REQ     requests. A remote attacker could use this issue to cause the daemon to crash, resulting in a denial of     service. This issue only affected Ubuntu 10.04 LTS and Ubuntu 12.04 LTS. (CVE-2013-1415)

    It was discovered that Kerberos incorrectly handled certain crafted TGS-REQ requests. A remote     authenticated attacker could use this issue to cause the daemon to crash, resulting in a denial of     service. This issue only affected Ubuntu 10.04 LTS and Ubuntu 12.04 LTS. (CVE-2013-1416)

    It was discovered that Kerberos incorrectly handled certain crafted requests when multiple realms were     configured. A remote attacker could use this issue to cause the daemon to crash, resulting in a denial of     service. This issue only affected Ubuntu 10.04 LTS and Ubuntu 12.04 LTS. (CVE-2013-1418, CVE-2013-6800)

    It was discovered that Kerberos incorrectly handled certain invalid tokens. If a remote attacker were able     to perform a machine-in-the-middle attack, this flaw could be used to cause the daemon to crash, resulting     in a denial of service. (CVE-2014-4341, CVE-2014-4342)

    It was discovered that Kerberos incorrectly handled certain mechanisms when used with SPNEGO. If a remote     attacker were able to perform a machine-in-the-middle attack, this flaw could be used to cause clients to     crash, resulting in a denial of service. (CVE-2014-4343)

    It was discovered that Kerberos incorrectly handled certain continuation tokens during SPNEGO     negotiations. A remote attacker could use this issue to cause the daemon to crash, resulting in a denial     of service. (CVE-2014-4344)

    Tomas Kuthan and Greg Hudson discovered that the Kerberos kadmind daemon incorrectly handled buffers when     used with the LDAP backend. A remote attacker could use this issue to cause the daemon to crash, resulting     in a denial of service, or possibly execute arbitrary code. (CVE-2014-4345)

Tenable has extracted the preceding description block directly from the Ubuntu 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-201312-12 (MIT Kerberos 5: Multiple vulnerabilities)

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

    A remote attacker could send a specially crafted request, possibly       resulting in execution of arbitrary code with the privileges of the       process or a Denial of Service condition. Additionally, a remote attacker       could impersonate a kadmind server and send a specially crafted packet to       the password change port, which can result in a ping-pong condition and a       Denial of Service condition.
  Workaround :

    There is no known workaround at this time.

ID	Name	Product	Family	Severity
79549	OracleVM 3.3 : krb5 (OVMSA-2014-0034)	Nessus	OracleVM Local Security Checks	high
79292	Amazon Linux AMI : krb5 (ALAS-2014-443)	Nessus	Amazon Linux Local Security Checks	high
79178	CentOS 6 : krb5 (CESA-2014:1389)	Nessus	CentOS Local Security Checks	high
78846	Scientific Linux Security Update : krb5 on SL6.x i386/x86_64 (20141014)	Nessus	Scientific Linux Local Security Checks	high
78523	Oracle Linux 6 : krb5 (ELSA-2014-1389)	Nessus	Oracle Linux Local Security Checks	critical
78418	Scientific Linux Security Update : krb5 on SL5.x i386/x86_64 (20140916)	Nessus	Scientific Linux Local Security Checks	high
78406	RHEL 6 : krb5 (RHSA-2014:1389)	Nessus	Red Hat Local Security Checks	high
77992	CentOS 5 : krb5 (CESA-2014:1245)	Nessus	CentOS Local Security Checks	high
77738	Oracle Linux 5 : krb5 (ELSA-2014-1245)	Nessus	Oracle Linux Local Security Checks	high
77698	RHEL 5 : krb5 (RHSA-2014:1245)	Nessus	Red Hat Local Security Checks	high
77147	Ubuntu 14.04 LTS : Kerberos vulnerabilities (USN-2310-1)	Nessus	Ubuntu Local Security Checks	critical
71487	GLSA-201312-12 : MIT Kerberos 5: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	high

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CVE-2013-6800

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