US-CERT Technical Cyber Security Alert TA04-078A -- Multiple Vulnerabilities in OpenSSL

From: CERT Advisory (cert-advisory_at_cert.org)
Date: 03/18/04


Date: Thu, 18 Mar 2004 17:31:29 -0500
To: cert-advisory@cert.org


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Technical Cyber Security Alert TA04-078A

Multiple Vulnerabilities in OpenSSL

   Original release date: March 18, 2004
   Last revised: --
   Source: US-CERT

Systems Affected

     * Applications and systems that use the OpenSSL SSL/TLS library

Overview

   Several vulnerabilities in the OpenSSL SSL/TLS library could allow an
   unauthenticated, remote attacker to cause a denial of service.

I. Description

   OpenSSL implements the Secure Sockets Layer (SSL) and Transport Layer
   Security (TLS) protocols and includes a general purpose cryptographic
   library. SSL and TLS are commonly used to provide authentication,
   encryption, integrity, and non-repudiation services to network
   applications including HTTP, IMAP, POP3, SMTP, and LDAP. OpenSSL is
   widely deployed across a variety of platforms and systems. In
   particular, many routers and other types of networking equipment use
   OpenSSL.

   The U.K. National Infrastructure Security Co-ordination Centre (NISCC)
   and the OpenSSL Project have reported three vulnerabilities in the
   OpenSSL SSL/TLS library (libssl). Any application or system that uses
   this library may be affected.

   VU#288574 - OpenSSL contains null-pointer assignment in
   do_change_cipher_spec() function

     Versions of OpenSSL from 0.9.6c to 0.9.6k inclusive and 0.9.7a to
     0.9.7c inclusive contain a null-pointer assignment in the
     do_change_cipher_spec() function. By performing a specially crafted
     SSL/TLS handshake, an attacker could cause OpenSSL to crash, which
     may result in a denial of service in the target application.
     
     (Other resources: OpenSSL Security Advisory (1.), CAN-2004-0079,
     NISCC/224012/OpenSSL/1)

   VU#484726 - OpenSSL does not adequately validate length of Kerberos
   tickets during SSL/TLS handshake

     Versions 0.9.7a, 0.9.7b, and 0.9.7c of OpenSSL do not adequately
     validate the length of Kerberos tickets (RFC 2712) during an SSL/TLS
     handshake. OpenSSL is not configured to use Kerberos by default. By
     performing a specially crafted SSL/TLS handshake with an OpenSSL
     system configured to use Kerberos, an attacker could cause OpenSSL
     to crash, which may result in a denial of service in the target
     application. OpenSSL 0.9.6 is not affected.
  
     (Other resources: OpenSSL Security Advisory (2.), CAN-2004-0112,
     NISCC/224012/OpenSSL/2)

   VU#465542 - OpenSSL does not properly handle unknown message types

     OpenSSL prior to version 0.9.6d does not properly handle unknown
     SSL/TLS message types. An attacker could cause the application using
     OpenSSL to enter an infinite loop, which may result in a denial of
     service in the target application. OpenSSL 0.9.7 is not affected.
  
     (Other resources: CAN-2004-0081, NISCC/224012/OpenSSL/3)

II. Impact

   An unauthenticated, remote attacker could cause a denial of service in
   any application or system that uses a vulnerable OpenSSL SSL/TLS
   library.

III. Solution

Upgrade or Apply a patch from your vendor

   Upgrade to OpenSSL 0.9.6m or 0.9.7d. Alternatively, upgrade or apply a
   patch as specified by your vendor. Note that it is necessary to
   recompile any applications that are statically linked to the OpenSSL
   SSL/TLS library.

Appendix A. Vendor Information

   Multiple vendors are affected by different combinations of these
   vulnerabilities. For updated information, please see the Systems
   Affected sections of VU#288574, VU#484726, and VU#465542.

Appendix B. References

     * US-CERT Technical Cyber Security Alert TA04-078A -
       <http://www.us-cert.gov/cas/techalerts/TA04-078A.html>
     * Vulnerability Note VU#288574 -
       <http://www.kb.cert.org/vuls/id/288574>
     * Vulnerability Note VU#484726 -
       <http://www.kb.cert.org/vuls/id/484726>
     * Vulnerability Note VU#465542 -
       <http://www.kb.cert.org/vuls/id/465542>
     * OpenSSL Security Advisory [17 March 2004] -
       <http://www.openssl.org/news/secadv_20040317.txt>
     * NISCC Vulnerability Advisory 224012 -
       <http://www.uniras.gov.uk/vuls/2004/224012/index.htm>
     * RFC 2712 Addition of Kerberos Cipher Suites to Transport Layer
       Security (TLS) - <http://www.ietf.org/rfc/rfc2712.txt>

     _________________________________________________________________

   These vulnerabilities were researched and reported by the OpenSSL
   Project and the U.K. National Infrastructure Security Co-ordination
   Centre (NISCC).
     _________________________________________________________________

   Feedback can be directed to the authors: Art Manion and Damon Morda.
     _________________________________________________________________

   Copyright 2004 Carnegie Mellon University. Terms of use.

   Revision History

   March 18, 2004: Initial release

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