Fwd: New OpenSSL releases fix denial of service attacks [17 March 2004]

Alex Potter alexp at apcuk.dyndns.org
Wed Mar 17 07:46:31 PST 2004



----------  Forwarded Message  ----------

Subject: New OpenSSL releases fix denial of service attacks [17 March 2004]
Date: Wednesday 17 March 2004 13:12
From: Mark J Cox <mark at awe.com>
To: full-disclosure at lists.netsys.com, <bugtraq at securityfocus.com>

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OpenSSL Security Advisory [17 March 2004]

Updated versions of OpenSSL are now available which correct two
security issues:


1. Null-pointer assignment during SSL handshake
===============================================

Testing performed by the OpenSSL group using the Codenomicon TLS Test
Tool uncovered a null-pointer assignment in the
do_change_cipher_spec() function.  A remote attacker could perform a
carefully crafted SSL/TLS handshake against a server that used the
OpenSSL library in such a way as to cause OpenSSL to crash.  Depending
on the application this could lead to a denial of service.

The Common Vulnerabilities and Exposures project (cve.mitre.org) has
assigned the name CAN-2004-0079 to this issue.

All versions of OpenSSL from 0.9.6c to 0.9.6k inclusive and from
0.9.7a to 0.9.7c inclusive are affected by this issue.  Any
application that makes use of OpenSSL's SSL/TLS library may be
affected.  Please contact your application vendor for details.


2. Out-of-bounds read affects Kerberos ciphersuites
===================================================

Stephen Henson discovered a flaw in SSL/TLS handshaking code when
using Kerberos ciphersuites.  A remote attacker could perform a
carefully crafted SSL/TLS handshake against a server configured to use
Kerberos ciphersuites in such a way as to cause OpenSSL to crash.
Most applications have no ability to use Kerberos ciphersuites and
will therefore be unaffected.

The Common Vulnerabilities and Exposures project (cve.mitre.org) has
assigned the name CAN-2004-0112 to this issue.

Versions 0.9.7a, 0.9.7b, and 0.9.7c of OpenSSL are affected by this
issue.  Any application that makes use of OpenSSL's SSL/TLS library
may be affected.  Please contact your application vendor for details.

Recommendations
- ---------------

Upgrade to OpenSSL 0.9.7d or 0.9.6m.  Recompile any OpenSSL applications
statically linked to OpenSSL libraries.

OpenSSL 0.9.7d and OpenSSL 0.9.6m are available for download via HTTP and
FTP from the following master locations (you can find the various FTP
mirrors under http://www.openssl.org/source/mirror.html):

    ftp://ftp.openssl.org/source/

The distribution file names are:

    o openssl-0.9.7d.tar.gz
      MD5 checksum: 1b49e90fc8a75c3a507c0a624529aca5

    o openssl-0.9.6m.tar.gz [normal]
      MD5 checksum: 1b63bfdca1c37837dddde9f1623498f9
    o openssl-engine-0.9.6m.tar.gz [engine]
      MD5 checksum: 4c39d2524bd466180f9077f8efddac8c

The checksums were calculated using the following command:

    openssl md5 openssl-0.9*.tar.gz

Credits
- -------

Patches for these issues were created by Dr Stephen Henson
(steve at openssl.org) of the OpenSSL core team.  The OpenSSL team would
like to thank Codenomicon for supplying the TLS Test Tool which was
used to discover these vulnerabilities, and Joe Orton of Red Hat for
performing the majority of the testing.

References
- ----------

http://www.codenomicon.com/testtools/tls/
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0079
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0112

URL for this Security Advisory:
http://www.openssl.org/news/secadv_20040317.txt


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