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Category:   Application (VPN)  >   OpenSSL Vendors:
(FreeBSD Issues Fix) OpenSSL Key Exchange Memory Corruption Error Lets Remote Users Deny Service
SecurityTracker Alert ID:  1024794
SecurityTracker URL:
CVE Reference:   CVE-2010-2939   (Links to External Site)
Date:  Nov 29 2010
Impact:   Denial of service via network, Execution of arbitrary code via network, User access via network
Fix Available:  Yes  Vendor Confirmed:  Yes  Exploit Included:  Yes  
Version(s): 1.0.0a; possibly other versions
Description:   A vulnerability was reported in OpenSSL. A remote user can cause denial of service conditions and may be able to execute arbitrary code on the target user's system.

A remote server can return specially crafted data to a connected client to trigger a memory corruption error and cause the target client to crash or potentially execute arbitrary code.

Georgi Guninski reported this vulnerability.

Impact:   A remote user can cause denial of service conditions.

A remote user may be able to execute arbitrary code on the target user's system.

Solution:   FreeBSD has issued a fix.

The FreeBSD advisory is available at:

Vendor URL: (Links to External Site)
Cause:   Access control error
Underlying OS:  UNIX (FreeBSD)
Underlying OS Comments:  7.1, 7.3, 8.0, 8.1

Message History:   This archive entry is a follow-up to the message listed below.
Aug 9 2010 OpenSSL Key Exchange Memory Corruption Error Lets Remote Users Deny Service

 Source Message Contents

Subject:  FreeBSD Security Advisory FreeBSD-SA-10:10.openssl

Hash: SHA1

FreeBSD-SA-10:10.openssl                                    Security Advisory
                                                          The FreeBSD Project

Topic:          OpenSSL multiple vulnerabilities

Category:       contrib
Module:         openssl
Announced:      2010-11-29
Credits:        Georgi Guninski, Rob Hulswit
Affects:        FreeBSD 7.0 and later
Corrected:      2010-11-26 22:50:58 UTC (RELENG_8, 8.1-STABLE)
                2010-11-29 20:43:06 UTC (RELENG_8_1, 8.1-RELEASE-p2)
                2010-11-29 20:43:06 UTC (RELENG_8_0, 8.0-RELEASE-p6)
                2010-11-28 13:45:51 UTC (RELENG_7, 7.3-STABLE)
                2010-11-29 20:43:06 UTC (RELENG_7_3, 7.3-RELEASE-p4)
                2010-11-29 20:43:06 UTC (RELENG_7_1, 7.1-RELEASE-p16)
CVE Name:       CVE-2010-2939, CVE-2010-3864

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:>.

I.   Background

FreeBSD includes software from the OpenSSL Project.  The OpenSSL Project is
a collaborative effort to develop a robust, commercial-grade, full-featured
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

A race condition exists in the OpenSSL TLS server extension code
parsing when used in a multi-threaded application, which uses
OpenSSL's internal caching mechanism.  The race condition can lead to
a buffer overflow. [CVE-2010-3864]

A double free exists in the SSL client ECDH handling code, when
processing specially crafted public keys with invalid prime
numbers. [CVE-2010-2939]

III. Impact

For affected server applications, an attacker may be able to utilize
the buffer overflow to crash the application or potentially run
arbitrary code with the privileges of the application. [CVE-2010-3864].

It may be possible to cause a DoS or potentially execute arbitrary in
the context of the user connection to a malicious SSL server.

IV.  Workaround

No workaround is available, but CVE-2010-3864 only affects FreeBSD 8.0
and later.

It should also be noted that CVE-2010-3864 affects neither the Apache
HTTP server nor Stunnel.

V.   Solution

Perform one of the following:

1) Upgrade your vulnerable system to 7-STABLE or 8-STABLE, or to the
RELENG_8_1, RELENG_8_0, RELENG_7_3, or RELENG_7_1 security branch
dated after the correction date.

2) To update your vulnerable system via a source code patch:

The following patches have been verified to apply to FreeBSD 7.1, 7.3,
8.0 and 8.1 systems.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

[FreeBSD 7.x]
# fetch
# fetch

[FreeBSD 8.x]
# fetch
# fetch

b) Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch
# cd /usr/src/secure/lib/libssl
# make obj && make depend && make && make install

NOTE: On the amd64 platform, the above procedure will not update the
lib32 (i386 compatibility) libraries.  On amd64 systems where the i386
compatibility libraries are used, the operating system should instead
be recompiled as described in

3) To update your vulnerable system via a binary patch:

Systems running 7.1-RELEASE, 7.3-RELEASE, 8.0-RELEASE or 8.1-RELEASE
on the i386 or amd64 platforms can be updated via the
freebsd-update(8) utility:

# freebsd-update fetch
# freebsd-update install

VI.  Correction details

The following list contains the revision numbers of each file that was
corrected in FreeBSD.


Branch                                                           Revision
- -------------------------------------------------------------------------
  src/UPDATING                                             1.507.
  src/UPDATING                                            1.507.
  src/UPDATING                                             1.632.
  src/UPDATING                                              1.632.
- -------------------------------------------------------------------------


Branch/path                                                      Revision
- -------------------------------------------------------------------------
stable/7/                                                         r215997
releng/7.3/                                                       r216063
releng/7.1/                                                       r216063
stable/8/                                                         r215912
releng/8.0/                                                       r216063
releng/8.1/                                                       r216063
- -------------------------------------------------------------------------

VII. References

The latest revision of this advisory is available at
Version: GnuPG v1.4.9

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