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

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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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