ID CVE-2015-2694
Summary The kdcpreauth modules in MIT Kerberos 5 (aka krb5) 1.12.x and 1.13.x before 1.13.2 do not properly track whether a client's request has been validated, which allows remote attackers to bypass an intended preauthentication requirement by providing (1) zero bytes of data or (2) an arbitrary realm name, related to plugins/preauth/otp/main.c and plugins/preauth/pkinit/pkinit_srv.c.
References
Vulnerable Configurations
  • MIT Kerberos 5 1.12
    cpe:2.3:a:mit:kerberos:5-1.12
  • MIT Kerberos 5 1.12.1
    cpe:2.3:a:mit:kerberos:5-1.12.1
  • MIT Kerberos 5 1.12.2
    cpe:2.3:a:mit:kerberos:5-1.12.2
  • MIT Kerberos 5 1.12.3
    cpe:2.3:a:mit:kerberos:5-1.12.3
  • MIT Kerberos 5-1.13
    cpe:2.3:a:mit:kerberos:5-1.13
  • MIT Kerberos 5 1.13.1
    cpe:2.3:a:mit:kerberos:5-1.13.1
CVSS
Base: 5.8 (as of 27-05-2015 - 09:52)
Impact:
Exploitability:
CWE CWE-264
CAPEC
  • Accessing, Modifying or Executing Executable Files
    An attack of this type exploits a system's configuration that allows an attacker to either directly access an executable file, for example through shell access; or in a possible worst case allows an attacker to upload a file and then execute it. Web servers, ftp servers, and message oriented middleware systems which have many integration points are particularly vulnerable, because both the programmers and the administrators must be in synch regarding the interfaces and the correct privileges for each interface.
  • Leverage Executable Code in Non-Executable Files
    An attack of this type exploits a system's trust in configuration and resource files, when the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high. The attack can be directed at a client system, such as causing buffer overrun through loading seemingly benign image files, as in Microsoft Security Bulletin MS04-028 where specially crafted JPEG files could cause a buffer overrun once loaded into the browser. Another example targets clients reading pdf files. In this case the attacker simply appends javascript to the end of a legitimate url for a pdf (http://www.gnucitizen.org/blog/danger-danger-danger/) http://path/to/pdf/file.pdf#whatever_name_you_want=javascript:your_code_here The client assumes that they are reading a pdf, but the attacker has modified the resource and loaded executable javascript into the client's browser process. The attack can also target server processes. The attacker edits the resource or configuration file, for example a web.xml file used to configure security permissions for a J2EE app server, adding role name "public" grants all users with the public role the ability to use the administration functionality. The server trusts its configuration file to be correct, but when they are manipulated, the attacker gains full control.
  • Blue Boxing
    This type of attack against older telephone switches and trunks has been around for decades. A tone is sent by an adversary to impersonate a supervisor signal which has the effect of rerouting or usurping command of the line. While the US infrastructure proper may not contain widespread vulnerabilities to this type of attack, many companies are connected globally through call centers and business process outsourcing. These international systems may be operated in countries which have not upgraded Telco infrastructure and so are vulnerable to Blue boxing. Blue boxing is a result of failure on the part of the system to enforce strong authorization for administrative functions. While the infrastructure is different than standard current applications like web applications, there are historical lessons to be learned to upgrade the access control for administrative functions.
  • Restful Privilege Elevation
    Rest uses standard HTTP (Get, Put, Delete) style permissions methods, but these are not necessarily correlated generally with back end programs. Strict interpretation of HTTP get methods means that these HTTP Get services should not be used to delete information on the server, but there is no access control mechanism to back up this logic. This means that unless the services are properly ACL'd and the application's service implementation are following these guidelines then an HTTP request can easily execute a delete or update on the server side. The attacker identifies a HTTP Get URL such as http://victimsite/updateOrder, which calls out to a program to update orders on a database or other resource. The URL is not idempotent so the request can be submitted multiple times by the attacker, additionally, the attacker may be able to exploit the URL published as a Get method that actually performs updates (instead of merely retrieving data). This may result in malicious or inadvertent altering of data on the server.
  • Target Programs with Elevated Privileges
    This attack targets programs running with elevated privileges. The attacker would try to leverage a bug in the running program and get arbitrary code to execute with elevated privileges. For instance an attacker would look for programs that write to the system directories or registry keys (such as HKLM, which stores a number of critical Windows environment variables). These programs are typically running with elevated privileges and have usually not been designed with security in mind. Such programs are excellent exploit targets because they yield lots of power when they break. The malicious user try to execute its code at the same level as a privileged system call.
  • Manipulating Input to File System Calls
    An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.
Access
VectorComplexityAuthentication
NETWORK MEDIUM NONE
Impact
ConfidentialityIntegrityAvailability
PARTIAL PARTIAL NONE
nessus via4
  • NASL family Ubuntu Local Security Checks
    NASL id UBUNTU_USN-2810-1.NASL
    description 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). 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.
    last seen 2019-02-21
    modified 2018-12-01
    plugin id 86872
    published 2015-11-13
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=86872
    title Ubuntu 12.04 LTS / 14.04 LTS / 15.04 / 15.10 : krb5 vulnerabilities (USN-2810-1)
  • NASL family Scientific Linux Local Security Checks
    NASL id SL_20151119_KRB5_ON_SL7_X.NASL
    description 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.
    last seen 2019-02-21
    modified 2018-12-28
    plugin id 87560
    published 2015-12-22
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=87560
    title Scientific Linux Security Update : krb5 on SL7.x x86_64
  • NASL family FreeBSD Local Security Checks
    NASL id FREEBSD_PKG_406636FE055D11E5AAB1D050996490D0.NASL
    description MIT reports : 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.
    last seen 2019-02-21
    modified 2018-11-10
    plugin id 83901
    published 2015-05-29
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=83901
    title FreeBSD : krb5 -- requires_preauth bypass in PKINIT-enabled KDC (406636fe-055d-11e5-aab1-d050996490d0)
  • NASL family Red Hat Local Security Checks
    NASL id REDHAT-RHSA-2015-2154.NASL
    description 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.
    last seen 2019-02-21
    modified 2018-11-10
    plugin id 86933
    published 2015-11-19
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=86933
    title RHEL 7 : krb5 (RHSA-2015:2154)
  • NASL family CentOS Local Security Checks
    NASL id CENTOS_RHSA-2015-2154.NASL
    description 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.
    last seen 2019-02-21
    modified 2018-11-10
    plugin id 87136
    published 2015-12-02
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=87136
    title CentOS 7 : krb5 (CESA-2015:2154)
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2015-7866.NASL
    description Security fix for CVE-2015-2694 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.
    last seen 2019-02-21
    modified 2016-08-02
    plugin id 83340
    published 2015-05-12
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=83340
    title Fedora 22 : krb5-1.13.1-3.fc22 (2015-7866)
  • NASL family SuSE Local Security Checks
    NASL id SUSE_SU-2015-1276-1.NASL
    description 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.
    last seen 2019-02-21
    modified 2018-11-29
    plugin id 84914
    published 2015-07-22
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=84914
    title SUSE SLES12 Security Update : krb5 (SUSE-SU-2015:1276-1)
  • NASL family Amazon Linux Local Security Checks
    NASL id ALA_ALAS-2015-624.NASL
    description 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.
    last seen 2019-02-21
    modified 2018-04-18
    plugin id 87350
    published 2015-12-15
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=87350
    title Amazon Linux AMI : krb5 (ALAS-2015-624)
  • NASL family Oracle Linux Local Security Checks
    NASL id ORACLELINUX_ELSA-2015-2154.NASL
    description From Red Hat Security Advisory 2015:2154 : 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.
    last seen 2019-02-21
    modified 2018-07-24
    plugin id 87026
    published 2015-11-24
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=87026
    title Oracle Linux 7 : krb5 (ELSA-2015-2154)
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2015-7878.NASL
    description Security fix for CVE-2015-2694 Security fix for CVE-2014-5353 (this was fixed in an older build but the announcement was lost) 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.
    last seen 2019-02-21
    modified 2016-08-02
    plugin id 84305
    published 2015-06-22
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=84305
    title Fedora 21 : krb5-1.12.2-17.fc21 (2015-7878)
redhat via4
advisories
bugzilla
id 1259846
title KDC does not return proper client principal for client referrals
oval
AND
  • OR
    • comment Red Hat Enterprise Linux 7 Client is installed
      oval oval:com.redhat.rhsa:tst:20140675001
    • comment Red Hat Enterprise Linux 7 Server is installed
      oval oval:com.redhat.rhsa:tst:20140675002
    • comment Red Hat Enterprise Linux 7 Workstation is installed
      oval oval:com.redhat.rhsa:tst:20140675003
    • comment Red Hat Enterprise Linux 7 ComputeNode is installed
      oval oval:com.redhat.rhsa:tst:20140675004
  • OR
    • AND
      • comment krb5-devel is earlier than 0:1.13.2-10.el7
        oval oval:com.redhat.rhsa:tst:20152154013
      • comment krb5-devel is signed with Red Hat redhatrelease2 key
        oval oval:com.redhat.rhsa:tst:20100863012
    • AND
      • comment krb5-libs is earlier than 0:1.13.2-10.el7
        oval oval:com.redhat.rhsa:tst:20152154005
      • comment krb5-libs is signed with Red Hat redhatrelease2 key
        oval oval:com.redhat.rhsa:tst:20100863016
    • AND
      • comment krb5-pkinit is earlier than 0:1.13.2-10.el7
        oval oval:com.redhat.rhsa:tst:20152154011
      • comment krb5-pkinit is signed with Red Hat redhatrelease2 key
        oval oval:com.redhat.rhsa:tst:20150439006
    • AND
      • comment krb5-server is earlier than 0:1.13.2-10.el7
        oval oval:com.redhat.rhsa:tst:20152154007
      • comment krb5-server is signed with Red Hat redhatrelease2 key
        oval oval:com.redhat.rhsa:tst:20100863010
    • AND
      • comment krb5-server-ldap is earlier than 0:1.13.2-10.el7
        oval oval:com.redhat.rhsa:tst:20152154009
      • comment krb5-server-ldap is signed with Red Hat redhatrelease2 key
        oval oval:com.redhat.rhsa:tst:20100863006
    • AND
      • comment krb5-workstation is earlier than 0:1.13.2-10.el7
        oval oval:com.redhat.rhsa:tst:20152154015
      • comment krb5-workstation is signed with Red Hat redhatrelease2 key
        oval oval:com.redhat.rhsa:tst:20100863014
rhsa
id RHSA-2015:2154
released 2015-11-19
severity Moderate
title RHSA-2015:2154: krb5 security, bug fix, and enhancement update (Moderate)
rpms
  • krb5-devel-0:1.13.2-10.el7
  • krb5-libs-0:1.13.2-10.el7
  • krb5-pkinit-0:1.13.2-10.el7
  • krb5-server-0:1.13.2-10.el7
  • krb5-server-ldap-0:1.13.2-10.el7
  • krb5-workstation-0:1.13.2-10.el7
refmap via4
bid 74824
confirm
ubuntu USN-2810-1
Last major update 07-12-2016 - 13:10
Published 25-05-2015 - 15:59
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