Can anyone define exceptionally large as noted in this statement?:
NOTE ALSO: The above patch reduces the functionality of libcrypto(3) by
prohibiting the use of exceptionally large public keys. It is believed
that no existing applications legitimately use such key lengths as would
be affected by this change.
It would be nice if exceptionally large were replaced with keys in
excess of x bits in size or something. I don't expect that this will
affect me, but ambiguous statements like that make me uncomfortable.
Begin forwarded message:
Date: Thu, 28 Sep 2006 13:13:53 GMT
From: FreeBSD Security Advisories [EMAIL PROTECTED]
To: FreeBSD Security Advisories [EMAIL PROTECTED]
Cc:
Subject: [FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-06:23.openssl
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FreeBSD-SA-06:23.opensslSecurity Advisory
The FreeBSD Project
Topic: Multiple problems in crypto(3)
Category: contrib
Module: openssl
Announced: 2006-09-28
Credits:Dr S N Henson, Tavis Ormandy, Will Drewry
Affects:All FreeBSD releases.
Corrected: 2006-09-28 13:02:37 UTC (RELENG_6, 6.1-PRERELEASE)
2006-09-28 13:03:14 UTC (RELENG_6_1, 6.1-RELEASE-p8)
2006-09-28 13:03:41 UTC (RELENG_6_0, 6.0-RELEASE-p13)
2006-09-28 13:03:57 UTC (RELENG_5, 5.5-STABLE)
2006-09-28 13:04:16 UTC (RELENG_5_5, 5.5-RELEASE-p6)
2006-09-28 13:04:47 UTC (RELENG_5_4, 5.4-RELEASE-p20)
2006-09-28 13:05:08 UTC (RELENG_5_3, 5.3-RELEASE-p35)
2006-09-28 13:05:59 UTC (RELENG_4, 4.11-STABLE)
2006-09-28 13:06:23 UTC (RELENG_4_11, 4.11-RELEASE-p23)
CVE Name: CVE-2006-2937, CVE-2006-2940, CVE-2006-3738, CVE-2006-4343
For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit URL:http://security.FreeBSD.org/.
I. Background
FreeBSD includes software from the OpenSSL Project. The OpenSSL Project is
a collaborative effort to develop a robust, commercial-grade, full-featured,
and Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3)
and Transport Layer Security (TLS v1) protocols as well as a full-strength
general purpose cryptography library.
II. Problem Description
Several problems have been found in OpenSSL:
1. During the parsing of certain invalid ASN1 structures an error condition
is mishandled, possibly resulting in an infinite loop. [CVE-2006-2937]
2. A buffer overflow exists in the SSL_get_shared_ciphers function.
[CVE-2006-3738]
3. A NULL pointer may be dereferenced in the SSL version 2 client code.
[CVE-2006-4343]
In addition, many applications using OpenSSL do not perform any validation
of the lengths of public keys being used. [CVE-2006-2940]
III. Impact
Servers which parse ASN1 data from untrusted sources may be vulnerable to
a denial of service attack. [CVE-2006-2937]
An attacker accessing a server which uses SSL version 2 may be able to
execute arbitrary code with the privileges of that server. [CVE-2006-3738]
A malicious SSL server can cause clients connecting using SSL version 2 to
crash. [CVE-2006-4343]
Applications which perform public key operations using untrusted keys may
be vulnerable to a denial of service attack. [CVE-2006-2940]
IV. Workaround
No workaround is available, but not all of the vulnerabilities mentioned
affect all applications.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to 4-STABLE, 5-STABLE, or 6-STABLE,
or to the RELENG_6_1, RELENG_6_0, RELENG_5_5, RELENG_5_4, RELENG_5_3,
or RELENG_4_11 security branch dated after the correction date.
2) To patch your present system:
The following patches have been verified to apply to FreeBSD 4.11, 5.3,
5.4, 5.5, 6.0, and 6.1 systems.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
# fetch http://security.FreeBSD.org/patches/SA-06:23/openssl.patch
# fetch http://security.FreeBSD.org/patches/SA-06:23/openssl.patch.asc
b) Execute the following commands as root:
# cd /usr/src
# patch /path/to/patch
c) Recompile the operating system as described in
URL: http://www.freebsd.org/handbook/makeworld.html and reboot the
system.
NOTE: Any third-party applications, including those installed from the
FreeBSD ports collection, which are statically linked to libcrypto(3)
should be recompiled in order to use the corrected code.
NOTE ALSO: The above patch reduces the functionality of libcrypto(3) by
prohibiting the use of exceptionally large public keys. It is believed
that no existing applications legitimately use such key lengths as would
be affected by this change.
VI.
