Synopsis

Critical: krb5 security and bugfix update

Type/Severity

Security Advisory: Critical

Topic

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

This update has been rated as having critical security impact by the Red
Hat Security Response Team.

Description

Kerberos is a network authentication system which allows clients and
servers to authenticate to each other through use of symmetric encryption
and a trusted third party, the KDC.

A flaw was found in the way the MIT Kerberos Authentication Service and Key
Distribution Center server (krb5kdc) handled Kerberos v4 protocol packets.
An unauthenticated remote attacker could use this flaw to crash the
krb5kdc daemon, disclose portions of its memory, or possibly execute
arbitrary code using malformed or truncated Kerberos v4 protocol requests.
(CVE-2008-0062, CVE-2008-0063)

This issue only affected krb5kdc with Kerberos v4 protocol compatibility
enabled, which is the default setting on Red Hat Enterprise Linux 4.
Kerberos v4 protocol support can be disabled by adding "v4_mode=none"
(without the quotes) to the "[kdcdefaults]" section of
/var/kerberos/krb5kdc/kdc.conf.

Jeff Altman of Secure Endpoints discovered a flaw in the RPC library as
used by MIT Kerberos kadmind server. An unauthenticated remote attacker
could use this flaw to crash kadmind or possibly execute arbitrary code.
This issue only affected systems with certain resource limits configured
and did not affect systems using default resource limits used by Red Hat
Enterprise Linux 5. (CVE-2008-0947)

Red Hat would like to thank MIT for reporting these issues.

Multiple memory management flaws were discovered in the GSSAPI library used
by MIT Kerberos. These flaws could possibly result in use of already freed
memory or an attempt to free already freed memory blocks (double-free
flaw), possibly causing a crash or arbitrary code execution.
(CVE-2007-5901, CVE-2007-5971)

In addition to the security issues resolved above, the following bugs were
also fixed:

• delegated krb5 credentials were not properly stored when SPNEGO was the
  underlying mechanism during GSSAPI authentication. Consequently,
  applications attempting to copy delegated Kerberos 5 credentials into a
  credential cache received an "Invalid credential was supplied" message
  rather than a copy of the delegated credentials. With this update, SPNEGO
  credentials can be properly searched, allowing applications to copy
  delegated credentials as expected.
  
• applications can initiate context acceptance (via gss_accept_sec_context)
  without passing a ret_flags value that would indicate that credentials were
  delegated. A delegated credential handle should have been returned in such
  instances. This updated package adds a temp_ret_flag that stores the
  credential status in the event no other ret_flags value is passed by an
  application calling gss_accept_sec_context.
  
• kpasswd did not fallback to TCP on receipt of certain errors, or when a
  packet was too big for UDP. This update corrects this.
  
• when the libkrb5 password-routine generated a set-password or
  change-password request, incorrect sequence numbers were generated for all
  requests subsequent to the first request. This caused password change
  requests to fail if the primary server was unavailable. This updated
  package corrects this by saving the sequence number value after the AP-REQ
  data is built and restoring this value before the request is generated.
  
• when a user's password expired, kinit would not prompt that user to
  change the password, instead simply informing the user their password had
  expired. This update corrects this behavior: kinit now prompts for a new
  password to be set when a password has expired.
  

All krb5 users are advised to upgrade to these updated packages, which
contain backported fixes to address these vulnerabilities and fix these
bugs.

Solution

Before applying this update, make sure that all previously-released
errata relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use
the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/FAQ_58_10188

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Server - Extended Update Support 5.1 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support 5.1 ia64
• Red Hat Enterprise Linux Server - Extended Update Support 5.1 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 5.1 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 5.1 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 415321 - CVE-2007-5901 krb5: use-after-free in gssapi lib
• BZ - 415351 - CVE-2007-5971 krb5: double free in gssapi lib
• BZ - 432620 - CVE-2008-0062 krb5: uninitialized pointer use in krb5kdc
• BZ - 432621 - CVE-2008-0063 krb5: possible leak of sensitive data from krb5kdc using krb4 request
• BZ - 433596 - CVE-2008-0947 krb5: file descriptor array overflow in RPC library
• BZ - 436460 - gss_krb5_copy_ccache can't find delegated Kerberos creds when using SPNEGO
• BZ - 436465 - gss_init_sec_context() mechglue wrapper doesn't handle ret_flags right
• BZ - 436467 - kpasswd does not fallback to tcp
• BZ - 436468 - krb5 password changing uses incorrect sequence numbers for every server but the first
• BZ - 436470 - kinit does not automatically start a password change when password is expired

CVEs

• CVE-2007-5971
• CVE-2008-0063
• CVE-2008-0062
• CVE-2007-5901
• CVE-2008-0947

References

• http://www.redhat.com/security/updates/classification/#critical

Red Hat Enterprise Linux Server 5

SRPM
krb5-1.6.1-17.el5_1.1.src.rpm	SHA-256: a2efb7e71fb1f8d2a77b1bdb18925c1f60fe08c6fd2dc8d2bd8e733f9441fd3d
x86_64
krb5-devel-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 6e5ecc26a0f46b43a6f9401e821493ec350ad43bdc109759fe82b835ced2bf8e
krb5-devel-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: e476fc55fda8fcf3c4572e35fb9c6520543250f395dc18dbeaccfce91412eca4
krb5-libs-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 2e906e3568843e2bffa5f9689c29fa324325c5b7ca442f48b2cd97820616fd27
krb5-libs-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: 14bbc0b54342f88296fe9a108559cc6d97c01787c995ef2931f4850f4e1ac90b
krb5-server-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: 244644387213d60cd1e71f48f6d04f6b21cdfd27ec6d21fdbaab34249c16378e
krb5-workstation-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: f2b2d3a98ef916c9c07271651706c1ca3787f47c64a474c73799198d79d1f949
ia64
krb5-devel-1.6.1-17.el5_1.1.ia64.rpm	SHA-256: 4ae1f8bc61dac632dcf9f83f4e2561733c84ef6b6f1993fe55240035c74ab26e
krb5-libs-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 2e906e3568843e2bffa5f9689c29fa324325c5b7ca442f48b2cd97820616fd27
krb5-libs-1.6.1-17.el5_1.1.ia64.rpm	SHA-256: 56c86567ffee9b2f94f49873d37c129cf716ccfcfd1e364d85acdd63288fea6a
krb5-server-1.6.1-17.el5_1.1.ia64.rpm	SHA-256: a4fa3c971d82d7aa48e8bf59323174a7a7a024923d43183ad58c20f50dad2d93
krb5-workstation-1.6.1-17.el5_1.1.ia64.rpm	SHA-256: bea870ed1350a367fce0b04c5616e093a8491dfcfe33e55bb7e9fa85e299cd01
i386
krb5-devel-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 6e5ecc26a0f46b43a6f9401e821493ec350ad43bdc109759fe82b835ced2bf8e
krb5-libs-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 2e906e3568843e2bffa5f9689c29fa324325c5b7ca442f48b2cd97820616fd27
krb5-server-1.6.1-17.el5_1.1.i386.rpm	SHA-256: b936dc3480c6174b787c3ceee54524ae7a24e72a930e72dda6c1bbe582f16e4a
krb5-workstation-1.6.1-17.el5_1.1.i386.rpm	SHA-256: e3e9fa0d220cd65073dc8e5368f6b49c44f32577d8b933e0391f3b630144e370

Red Hat Enterprise Linux Workstation 5

SRPM
krb5-1.6.1-17.el5_1.1.src.rpm	SHA-256: a2efb7e71fb1f8d2a77b1bdb18925c1f60fe08c6fd2dc8d2bd8e733f9441fd3d
x86_64
krb5-devel-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 6e5ecc26a0f46b43a6f9401e821493ec350ad43bdc109759fe82b835ced2bf8e
krb5-devel-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: e476fc55fda8fcf3c4572e35fb9c6520543250f395dc18dbeaccfce91412eca4
krb5-libs-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 2e906e3568843e2bffa5f9689c29fa324325c5b7ca442f48b2cd97820616fd27
krb5-libs-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: 14bbc0b54342f88296fe9a108559cc6d97c01787c995ef2931f4850f4e1ac90b
krb5-server-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: 244644387213d60cd1e71f48f6d04f6b21cdfd27ec6d21fdbaab34249c16378e
krb5-workstation-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: f2b2d3a98ef916c9c07271651706c1ca3787f47c64a474c73799198d79d1f949
i386
krb5-devel-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 6e5ecc26a0f46b43a6f9401e821493ec350ad43bdc109759fe82b835ced2bf8e
krb5-libs-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 2e906e3568843e2bffa5f9689c29fa324325c5b7ca442f48b2cd97820616fd27
krb5-server-1.6.1-17.el5_1.1.i386.rpm	SHA-256: b936dc3480c6174b787c3ceee54524ae7a24e72a930e72dda6c1bbe582f16e4a
krb5-workstation-1.6.1-17.el5_1.1.i386.rpm	SHA-256: e3e9fa0d220cd65073dc8e5368f6b49c44f32577d8b933e0391f3b630144e370

Red Hat Enterprise Linux Desktop 5

SRPM
krb5-1.6.1-17.el5_1.1.src.rpm	SHA-256: a2efb7e71fb1f8d2a77b1bdb18925c1f60fe08c6fd2dc8d2bd8e733f9441fd3d
x86_64
krb5-libs-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 2e906e3568843e2bffa5f9689c29fa324325c5b7ca442f48b2cd97820616fd27
krb5-libs-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: 14bbc0b54342f88296fe9a108559cc6d97c01787c995ef2931f4850f4e1ac90b
krb5-workstation-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: f2b2d3a98ef916c9c07271651706c1ca3787f47c64a474c73799198d79d1f949
i386
krb5-libs-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 2e906e3568843e2bffa5f9689c29fa324325c5b7ca442f48b2cd97820616fd27
krb5-workstation-1.6.1-17.el5_1.1.i386.rpm	SHA-256: e3e9fa0d220cd65073dc8e5368f6b49c44f32577d8b933e0391f3b630144e370

Red Hat Enterprise Linux for IBM z Systems 5

SRPM
krb5-1.6.1-17.el5_1.1.src.rpm	SHA-256: a2efb7e71fb1f8d2a77b1bdb18925c1f60fe08c6fd2dc8d2bd8e733f9441fd3d
s390x
krb5-devel-1.6.1-17.el5_1.1.s390.rpm	SHA-256: 9622a72f9a71d9d12a4c92b5a96b776dcb7a95007ea534175f25c99532b33c0f
krb5-devel-1.6.1-17.el5_1.1.s390x.rpm	SHA-256: 25733c5ed71b21545d9d6295c445110e2bad0348c81a9e94957b5bf394fa1b5e
krb5-libs-1.6.1-17.el5_1.1.s390.rpm	SHA-256: 58d64130f912b22ef53af0b9dbddae4be13fce84959b7c552d12932306fdaf33
krb5-libs-1.6.1-17.el5_1.1.s390x.rpm	SHA-256: 9fa2f910c5d42222a316d42590b7860cf67e20d1e6949b8abccac826478e9e2e
krb5-server-1.6.1-17.el5_1.1.s390x.rpm	SHA-256: c32c412c3c982e49e89d0af30d39c6c7320201d452f9193f0bbc97a5a43a2ad1
krb5-workstation-1.6.1-17.el5_1.1.s390x.rpm	SHA-256: c1906d0b6468de43642d255fa7ca4b1875d70fe46e4fae881d88b0efa165eee2

Red Hat Enterprise Linux for Power, big endian 5

SRPM
krb5-1.6.1-17.el5_1.1.src.rpm	SHA-256: a2efb7e71fb1f8d2a77b1bdb18925c1f60fe08c6fd2dc8d2bd8e733f9441fd3d
ppc
krb5-devel-1.6.1-17.el5_1.1.ppc.rpm	SHA-256: 807c37a101a5aa9345bdc10a3f2321ed97ca3ef0aedbc44a241854498b5db6a1
krb5-devel-1.6.1-17.el5_1.1.ppc64.rpm	SHA-256: 8386cb3960314242f4cf0af956e7bb5a66312155d1c15d3fae751ffdd2cd69fe
krb5-libs-1.6.1-17.el5_1.1.ppc.rpm	SHA-256: 25a5d2402fecaa646737aeb9f2f92cabecbde1af936d5a0ff03dc190e884bdde
krb5-libs-1.6.1-17.el5_1.1.ppc64.rpm	SHA-256: 4cef9bdb2f0bec6b115c674439c3fa409a8deb23455db455f83596d86f53b76a
krb5-server-1.6.1-17.el5_1.1.ppc.rpm	SHA-256: b85a36a0bf9232d659852799ad9f0969b2f860069b0e788a9e99843c83d3b617
krb5-workstation-1.6.1-17.el5_1.1.ppc.rpm	SHA-256: 1d6dad7ba89d96a0d0b506d194700d2d5c486c7df822104978aec247a2ded7bf

Red Hat Enterprise Linux Server from RHUI 5

SRPM
krb5-1.6.1-17.el5_1.1.src.rpm	SHA-256: a2efb7e71fb1f8d2a77b1bdb18925c1f60fe08c6fd2dc8d2bd8e733f9441fd3d
x86_64
krb5-devel-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 6e5ecc26a0f46b43a6f9401e821493ec350ad43bdc109759fe82b835ced2bf8e
krb5-devel-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: e476fc55fda8fcf3c4572e35fb9c6520543250f395dc18dbeaccfce91412eca4
krb5-libs-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 2e906e3568843e2bffa5f9689c29fa324325c5b7ca442f48b2cd97820616fd27
krb5-libs-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: 14bbc0b54342f88296fe9a108559cc6d97c01787c995ef2931f4850f4e1ac90b
krb5-server-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: 244644387213d60cd1e71f48f6d04f6b21cdfd27ec6d21fdbaab34249c16378e
krb5-workstation-1.6.1-17.el5_1.1.x86_64.rpm	SHA-256: f2b2d3a98ef916c9c07271651706c1ca3787f47c64a474c73799198d79d1f949
i386
krb5-devel-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 6e5ecc26a0f46b43a6f9401e821493ec350ad43bdc109759fe82b835ced2bf8e
krb5-libs-1.6.1-17.el5_1.1.i386.rpm	SHA-256: 2e906e3568843e2bffa5f9689c29fa324325c5b7ca442f48b2cd97820616fd27
krb5-server-1.6.1-17.el5_1.1.i386.rpm	SHA-256: b936dc3480c6174b787c3ceee54524ae7a24e72a930e72dda6c1bbe582f16e4a
krb5-workstation-1.6.1-17.el5_1.1.i386.rpm	SHA-256: e3e9fa0d220cd65073dc8e5368f6b49c44f32577d8b933e0391f3b630144e370