MIT Kerberos 5 (aka krb5) through 1.13.1 incorrectly expects that a krb5_read_message data field is represented as a string ending with a '\0' character, which allows remote attackers to (1) cause a denial of service (NULL pointer dereference) via a zero-byte version string or (2) cause a denial of service (out-of-bounds read) by omitting the '\0' character, related to appl/user_user/server.c and lib/krb5/krb/recvauth.c.

The remote Redhat Enterprise Linux 5 host has one or more packages installed that are affected by multiple vulnerabilities that have been acknowledged by the vendor but will not be patched.

  - krb5: kadmind doubly frees partial deserialization results (MITKRB5-SA-2015-001) (CVE-2014-9421)

  - krb5: Automatic sec context deletion could lead to double-free (CVE-2017-11462)

  - The kadm5_randkey_principal_3 function in lib/kadm5/srv/svr_principal.c in kadmind in MIT Kerberos 5 (aka     krb5) before 1.13 sends old keys in a response to a -randkey -keepold request, which allows remote     authenticated users to forge tickets by leveraging administrative access. (CVE-2014-5351)

Note that Nessus has not tested for these issues but has instead relied on the package manager's report that the package is installed.

Kerberos, a system for authenticating users and services on a network, was affected by several vulnerabilities. The Common Vulnerabilities and Exposures project identifies the following issues.

CVE-2013-1418 Kerberos allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted request when multiple realms are configured.

CVE-2014-5351 Kerberos sends old keys in a response to a -randkey
-keepold request, which allows remote authenticated users to forge tickets by leveraging administrative access.

CVE-2014-5353 When the KDC uses LDAP, allows remote authenticated users to cause a denial of service (daemon crash) via a successful LDAP query with no results, as demonstrated by using an incorrect object type for a password policy.

CVE-2014-5355 Kerberos expects that a krb5_read_message data field is represented as a string ending with a '\0' character, which allows remote attackers to (1) cause a denial of service (NULL pointer dereference) via a zero-byte version string or (2) cause a denial of service (out-of-bounds read) by omitting the '\0' character,

CVE-2016-3119 Kerberos allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted request to modify a principal.

CVE-2016-3120 Kerberos allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) via an S4U2Self request.

For Debian 7 'Wheezy', these problems have been fixed in version 1.10.1+dfsg-5+deb7u9.

We recommend that you upgrade your krb5 packages.

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

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

  - Fix (CVE-2015-8629, CVE-2015-8631)

  - Also fix a spec trigger issue that prevents building

  - Resolves: #1306973

It was found that the krb5_read_message() function of MIT Kerberos did not correctly sanitize input, and could create invalid krb5_data objects. A remote, unauthenticated attacker could use this flaw to crash a Kerberos child process via a specially crafted request.
(CVE-2014-5355)

A flaw was found in the OTP kdcpreauth module of MIT kerberos. An unauthenticated remote attacker could use this flaw to bypass the requires_preauth flag on a client principal and obtain a ciphertext encrypted in the principal's long-term key. This ciphertext could be used to conduct an off-line dictionary attack against the user's password. (CVE-2015-2694)

The krb5 packages have been upgraded to upstream version 1.13.2, which provides a number of bug fixes and enhancements over the previous version.

Notably, this update fixes the following bugs :

  - Previously, the RADIUS support (libkrad) in krb5 was     sending krb5 authentication for Transmission Control     Protocol (TCP) transports multiple times, accidentally     using a code path intended to be used only for     unreliable transport types, for example User Datagram     Protocol (UDP) transports. A patch that fixes the     problem by disabling manual retries for reliable     transports, such as TCP, has been applied, and the     correct code path is now used in this situation.

  - Attempts to use Kerberos single sign-on (SSO) to access     SAP NetWeaver systems sometimes failed. The SAP     NetWeaver developer trace displayed the following error     message :

No credentials were supplied, or the credentials were unavailable or inaccessible Unable to establish the security context

Querying SSO credential lifetime has been modified to trigger credential acquisition, thus preventing the error from occurring. Now, the user can successfully use Kerberos SSO for accessing SAP NetWeaver systems.

A flaw was found in the OTP kdcpreauth module of MIT Kerberos. A remote attacker could use this flaw to bypass the requires_preauth flag on a client principal and obtain a ciphertext encrypted in the principal's long-term key. This ciphertext could be used to conduct an off-line dictionary attack against the user's password.

It was found that the krb5_read_message() function of MIT Kerberos did not correctly sanitize input, and could create invalid krb5_data objects. A remote, unauthenticated attacker could use this flaw to crash a Kerberos child process via a specially crafted request.

Updated krb5 packages that fix two security issues, several bugs, and add various enhancements are now available for Red Hat Enterprise Linux 7.

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 network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC).

It was found that the krb5_read_message() function of MIT Kerberos did not correctly sanitize input, and could create invalid krb5_data objects. A remote, unauthenticated attacker could use this flaw to crash a Kerberos child process via a specially crafted request.
(CVE-2014-5355)

A flaw was found in the OTP kdcpreauth module of MIT kerberos. An unauthenticated remote attacker could use this flaw to bypass the requires_preauth flag on a client principal and obtain a ciphertext encrypted in the principal's long-term key. This ciphertext could be used to conduct an off-line dictionary attack against the user's password. (CVE-2015-2694)

The krb5 packages have been upgraded to upstream version 1.13.2, which provides a number of bug fixes and enhancements over the previous version. (BZ#1203889)

Notably, this update fixes the following bugs :

* Previously, the RADIUS support (libkrad) in krb5 was sending krb5 authentication for Transmission Control Protocol (TCP) transports multiple times, accidentally using a code path intended to be used only for unreliable transport types, for example User Datagram Protocol (UDP) transports. A patch that fixes the problem by disabling manual retries for reliable transports, such as TCP, has been applied, and the correct code path is now used in this situation. (BZ#1251586)

* Attempts to use Kerberos single sign-on (SSO) to access SAP NetWeaver systems sometimes failed. The SAP NetWeaver developer trace displayed the following error message :

No credentials were supplied, or the credentials were unavailable or inaccessible Unable to establish the security context

Querying SSO credential lifetime has been modified to trigger credential acquisition, thus preventing the error from occurring. Now, the user can successfully use Kerberos SSO for accessing SAP NetWeaver systems. (BZ#1252454)

All krb5 users are advised to upgrade to these updated packages, which correct these issues and add these enhancements.

The remote Oracle Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2015-2154 advisory.

    - the rebase to krb5 1.13.1 in vers 1.13.1-0 also fixed:
      - Bug 1144498 ('Fix the race condition in the libkrb5 replay cache')
      - Bug 1163402 ('kdb5_ldap_util view_policy does not shows ticket flags on s390x and ppc64')
      - Bug 1185770 ('Missing upstream test in krb5-1.12.2: src/tests/gssapi/t_invalid.c')
      - Bug 1204211 ('CVE-2014-5355 krb5: unauthenticated denial of service in recvauth_common() and other')
    - fix for CVE-2015-2694 (#1218020) 'requires_preauth bypass       in PKINIT-enabled KDC'.
      In MIT krb5 1.12 and later, when the KDC is configured with       PKINIT support, an unauthenticated remote attacker can       bypass the requires_preauth flag on a client principal and       obtain a ciphertext encrypted in the principal's long-term       key.  This ciphertext could be used to conduct an off-line       dictionary attack against the user's password.

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 Redhat Enterprise Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2015:2154 advisory.

  - krb5: unauthenticated denial of service in recvauth_common() and others (CVE-2014-5355)

  - krb5: issues in OTP and PKINIT kdcpreauth modules leading to requires_preauth bypass (CVE-2015-2694)

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

The remote Ubuntu 14.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-2810-1 advisory.

    It was discovered that the Kerberos kpasswd service incorrectly handled certain UDP packets. A remote     attacker could possibly use this issue to cause resource consumption, resulting in a denial of service.
    This issue only affected Ubuntu 12.04 LTS. (CVE-2002-2443)

    It was discovered that Kerberos incorrectly handled null bytes in certain data fields. A remote attacker     could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 12.04 LTS and     Ubuntu 14.04 LTS. (CVE-2014-5355)

    It was discovered that the Kerberos kdcpreauth modules incorrectly tracked certain client requests. A     remote attacker could possibly use this issue to bypass intended preauthentication requirements. This     issue only affected Ubuntu 14.04 LTS and Ubuntu 15.04. (CVE-2015-2694)

    It was discovered that Kerberos incorrectly handled certain SPNEGO packets. A remote attacker could     possibly use this issue to cause a denial of service. (CVE-2015-2695)

    It was discovered that Kerberos incorrectly handled certain IAKERB packets. A remote attacker could     possibly use this issue to cause a denial of service. (CVE-2015-2696, CVE-2015-2698)

    It was discovered that Kerberos incorrectly handled certain TGS requests. A remote attacker could possibly     use this issue to cause a denial of service. (CVE-2015-2697)

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.

krb5 was updated to fix three security issues.

Remote authenticated users could cause denial of service.

These security issues were fixed :

  - CVE-2014-5353: NULL pointer dereference when using a     ticket policy name as password name (bsc#910457).

  - CVE-2014-5354: NULL pointer dereference when using     keyless entries (bsc#910458).

  - CVE-2014-5355: Denial of service in krb5_read_message     (bsc#918595).

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

krb5 was updated to fix four security issues.

These security issues were fixed :

  - CVE-2014-5353: NULL pointer dereference when using a     ticket policy name as password name (bsc#910457).

  - CVE-2014-5354: NULL pointer dereference when using     keyless entries (bsc#910458).

  - CVE-2014-5355: Denial of service in krb5_read_message     (bsc#918595).

  - CVE-2015-2694: OTP and PKINIT kdcpreauth modules leading     to requires_preauth bypass (bsc#928978).

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

The version of the Network Authentication Service (NAS) installed on the remote AIX host is affected by the following vulnerabilities related to Kerberos 5 :

  - Denial of service and remote code execution     vulnerabilities exist due to security context handles     not being properly maintained, allowing an     authenticated, remote attacker to crash the service or     execute arbitrary code using crafted GSSAPI traffic.
    (CVE-2014-5352)

  - A denial of service vulnerability exists due to improper     handling of zero-byte or unterminated strings.
    (CVE-2014-5355)

  - Denial of service and remote code execution     vulnerabilities exist which allow an authenticated,     remote attacker to crash the service or execute     arbitrary code using crafted, malformed XDR data.
    (CVE-2014-9421)

  - A privilege escalation vulnerability exists that allows     an authenticated, remote attacker to gain administrative     access via a flaw in kadmin authorization checks.
    (CVE-2014-9422)

  - An information disclosure vulnerability allows an     attacker to gain information about process heap memory     from NAS packets. (CVE-2014-9423)

A use-after-free flaw was found in the way the MIT Kerberos libgssapi_krb5 library processed valid context deletion tokens. An attacker able to make an application using the GSS-API library (libgssapi) could call the gss_process_context_token() function and use this flaw to crash that application. (CVE-2014-5352)

If kadmind were used with an LDAP back end for the KDC database, a remote, authenticated attacker who has the permissions to set the password policy could crash kadmind by attempting to use a named ticket policy object as a password policy for a principal.
(CVE-2014-5353)

It was found that the krb5_read_message() function of MIT Kerberos did not correctly sanitize input, and could create invalid krb5_data objects. A remote, unauthenticated attacker could use this flaw to crash a Kerberos child process via a specially crafted request.
(CVE-2014-5355)

A double-free flaw was found in the way MIT Kerberos handled invalid External Data Representation (XDR) data. An authenticated user could use this flaw to crash the MIT Kerberos administration server (kadmind), or other applications using Kerberos libraries, via specially crafted XDR packets. (CVE-2014-9421)

It was found that the MIT Kerberos administration server (kadmind) incorrectly accepted certain authentication requests for two-component server principal names. A remote attacker able to acquire a key with a particularly named principal (such as 'kad/x') could use this flaw to impersonate any user to kadmind, and perform administrative actions as that user. (CVE-2014-9422)

The following security issues are fixed with this release :

A use-after-free flaw was found in the way the MIT Kerberos libgssapi_krb5 library processed valid context deletion tokens. An attacker able to make an application using the GSS-API library (libgssapi) could call the gss_process_context_token() function and use this flaw to crash that application. (CVE-2014-5352)

If kadmind were used with an LDAP back end for the KDC database, a remote, authenticated attacker who has the permissions to set the password policy could crash kadmind by attempting to use a named ticket policy object as a password policy for a principal.
(CVE-2014-5353)

It was found that the krb5_read_message() function of MIT Kerberos did not correctly sanitize input, and could create invalid krb5_data objects. A remote, unauthenticated attacker could use this flaw to crash a Kerberos child process via a specially crafted request.
(CVE-2014-5355)

A double-free flaw was found in the way MIT Kerberos handled invalid External Data Representation (XDR) data. An authenticated user could use this flaw to crash the MIT Kerberos administration server (kadmind), or other applications using Kerberos libraries, via specially crafted XDR packets. (CVE-2014-9421)

It was found that the MIT Kerberos administration server (kadmind) incorrectly accepted certain authentication requests for two-component server principal names. A remote attacker able to acquire a key with a particularly named principal (such as 'kad/x') could use this flaw to impersonate any user to kadmind, and perform administrative actions as that user. (CVE-2014-9422)

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

  - fix for CVE-2014-5355 (#1193939) 'krb5: unauthenticated     denial of service in recvauth_common and others'

  - fix for CVE-2014-5353 (#1174543) 'Fix LDAP misused     policy name crash'

  - Changelog fixes to make errata subsystem happy.

  - fix for CVE-2014-5352 (#1179856)     'gss_process_context_token incorrectly frees context     (MITKRB5-SA-2015-001)'

  - fix for CVE-2014-9421 (#1179857) 'kadmind doubly frees     partial deserialization results (MITKRB5-SA-2015-001)'

  - fix for CVE-2014-9422 (#1179861) 'kadmind incorrectly     validates server principal name (MITKRB5-SA-2015-001)'

The remote Oracle Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2015-0794 advisory.

    - fix for CVE-2014-5355 (#1193939) 'krb5: unauthenticated       denial of service in recvauth_common() and others'
    - fix for CVE-2014-5353 (#1174543) 'Fix LDAP misused policy       name crash'
    - fix for CVE-2014-5352 (#1179856) 'gss_process_context_token()       incorrectly frees context (MITKRB5-SA-2015-001)'
    - fix for CVE-2014-9421 (#1179857) 'kadmind doubly frees partial       deserialization results (MITKRB5-SA-2015-001)'

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.

Updated krb5 packages that fix multiple security issues 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.

The following security issues are fixed with this release :

A use-after-free flaw was found in the way the MIT Kerberos libgssapi_krb5 library processed valid context deletion tokens. An attacker able to make an application using the GSS-API library (libgssapi) could call the gss_process_context_token() function and use this flaw to crash that application. (CVE-2014-5352)

If kadmind were used with an LDAP back end for the KDC database, a remote, authenticated attacker who has the permissions to set the password policy could crash kadmind by attempting to use a named ticket policy object as a password policy for a principal.
(CVE-2014-5353)

It was found that the krb5_read_message() function of MIT Kerberos did not correctly sanitize input, and could create invalid krb5_data objects. A remote, unauthenticated attacker could use this flaw to crash a Kerberos child process via a specially crafted request.
(CVE-2014-5355)

A double-free flaw was found in the way MIT Kerberos handled invalid External Data Representation (XDR) data. An authenticated user could use this flaw to crash the MIT Kerberos administration server (kadmind), or other applications using Kerberos libraries, via specially crafted XDR packets. (CVE-2014-9421)

It was found that the MIT Kerberos administration server (kadmind) incorrectly accepted certain authentication requests for two-component server principal names. A remote attacker able to acquire a key with a particularly named principal (such as 'kad/x') could use this flaw to impersonate any user to kadmind, and perform administrative actions as that user. (CVE-2014-9422)

Red Hat would like to thank the MIT Kerberos project for reporting CVE-2014-5352, CVE-2014-9421, and CVE-2014-9422. The MIT Kerberos project acknowledges Nico Williams for assisting with the analysis of CVE-2014-5352.

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

Multiple vulnerabilities has been discovered and corrected in krb5 :

The krb5_gss_process_context_token function in lib/gssapi/krb5/process_context_token.c in the libgssapi_krb5 library in MIT Kerberos 5 (aka krb5) through 1.11.5, 1.12.x through 1.12.2, and 1.13.x before 1.13.1 does not properly maintain security-context handles, which allows remote authenticated users to cause a denial of service (use-after-free and double free, and daemon crash) or possibly execute arbitrary code via crafted GSSAPI traffic, as demonstrated by traffic to kadmind (CVE-2014-5352).

MIT Kerberos 5 (aka krb5) through 1.13.1 incorrectly expects that a krb5_read_message data field is represented as a string ending with a '\0' character, which allows remote attackers to (1) cause a denial of service (NULL pointer dereference) via a zero-byte version string or (2) cause a denial of service (out-of-bounds read) by omitting the '\0' character, related to appl/user_user/server.c and lib/krb5/krb/recvauth.c (CVE-2014-5355).

The auth_gssapi_unwrap_data function in lib/rpc/auth_gssapi_misc.c in MIT Kerberos 5 (aka krb5) through 1.11.5, 1.12.x through 1.12.2, and 1.13.x before 1.13.1 does not properly handle partial XDR deserialization, which allows remote authenticated users to cause a denial of service (use-after-free and double free, and daemon crash) or possibly execute arbitrary code via malformed XDR data, as demonstrated by data sent to kadmind (CVE-2014-9421).

The check_rpcsec_auth function in kadmin/server/kadm_rpc_svc.c in kadmind in MIT Kerberos 5 (aka krb5) through 1.11.5, 1.12.x through 1.12.2, and 1.13.x before 1.13.1 allows remote authenticated users to bypass a kadmin/* authorization check and obtain administrative access by leveraging access to a two-component principal with an initial kadmind substring, as demonstrated by a ka/x principal (CVE-2014-9422).

The svcauth_gss_accept_sec_context function in lib/rpc/svc_auth_gss.c in MIT Kerberos 5 (aka krb5) 1.11.x through 1.11.5, 1.12.x through 1.12.2, and 1.13.x before 1.13.1 transmits uninitialized interposer data to clients, which allows remote attackers to obtain sensitive information from process heap memory by sniffing the network for data in a handle field (CVE-2014-9423).

The updated packages provides a solution for these security issues.

krb5 was updated to fix three security issues.

Remote authenticated users could cause denial of service.

On openSUSE 13.1 and 13.2 krb5 was updated to fix the following vulnerabilities :

  - bnc#910457: CVE-2014-5353: NULL pointer dereference when     using a ticket policy name as password name

  - bnc#918595: CVE-2014-5355: krb5: denial of service in     krb5_read_message On openSUSE 13.1 krb5 was updated to     fix the following vulnerability :

  - bnc#910458: CVE-2014-5354: NULL pointer dereference when     using keyless entries

ID	Name	Product	Family	Severity
199152	RHEL 5 : krb5 (Unpatched Vulnerability)	Nessus	Red Hat Local Security Checks	critical
106536	Debian DLA-1265-1 : krb5 security update	Nessus	Debian Local Security Checks	medium
90138	OracleVM 3.3 / 3.4 : krb5 (OVMSA-2016-0039)	Nessus	OracleVM Local Security Checks	medium
87560	Scientific Linux Security Update : krb5 on SL7.x x86_64 (20151119)	Nessus	Scientific Linux Local Security Checks	medium
87350	Amazon Linux AMI : krb5 (ALAS-2015-624)	Nessus	Amazon Linux Local Security Checks	medium
87136	CentOS 7 : krb5 (CESA-2015:2154)	Nessus	CentOS Local Security Checks	medium
87026	Oracle Linux 7 : krb5 (ELSA-2015-2154)	Nessus	Oracle Linux Local Security Checks	high
86933	RHEL 7 : krb5 (RHSA-2015:2154)	Nessus	Red Hat Local Security Checks	high
86872	Ubuntu 14.04 LTS : Kerberos vulnerabilities (USN-2810-1)	Nessus	Ubuntu Local Security Checks	high
84979	SUSE SLED11 / SLES11 Security Update : krb5 (SUSE-SU-2015:1282-1)	Nessus	SuSE Local Security Checks	medium
84914	SUSE SLES12 Security Update : krb5 (SUSE-SU-2015:1276-1)	Nessus	SuSE Local Security Checks	medium
83874	AIX NAS Advisory : nas_advisory3.asc	Nessus	AIX Local Security Checks	high
83269	Amazon Linux AMI : krb5 (ALAS-2015-518)	Nessus	Amazon Linux Local Security Checks	high
82694	Scientific Linux Security Update : krb5 on SL6.x i386/x86_64 (20150409)	Nessus	Scientific Linux Local Security Checks	high
82692	OracleVM 3.3 : krb5 (OVMSA-2015-0054)	Nessus	OracleVM Local Security Checks	high
82689	Oracle Linux 6 : krb5 (ELSA-2015-0794)	Nessus	Oracle Linux Local Security Checks	high
82667	CentOS 6 : krb5 (CESA-2015:0794)	Nessus	CentOS Local Security Checks	high
82656	RHEL 6 : krb5 (RHSA-2015:0794)	Nessus	Red Hat Local Security Checks	high
82322	Mandriva Linux Security Advisory : krb5 (MDVSA-2015:069)	Nessus	Mandriva Local Security Checks	high
81965	openSUSE Security Update : krb5 (openSUSE-2015-246)	Nessus	SuSE Local Security Checks	medium

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CVE-2014-5355

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