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National Cyber Alert System
Technical Cyber Security Alert TA04-078Aarchive

Multiple Vulnerabilities in OpenSSL

Original release date: March 18, 2004
Last revised: March 19, 2004
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


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
March 19, 2004: Added CVE CAN references VU# links
Last updated February 08, 2008
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