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Category:   Application (VPN)  >   OpenSSL Vendors:
(FreeBSD Issues Fix) OpenSSL Multiple Bugs Let Remote Users Deny Service and Obtain Potentially Sensitive Information
SecurityTracker Alert ID:  1037891
SecurityTracker URL:
CVE Reference:   CVE-2017-3731, CVE-2017-3732   (Links to External Site)
Date:  Feb 23 2017
Impact:   Denial of service via network, Disclosure of system information, Disclosure of user information
Fix Available:  Yes  Vendor Confirmed:  Yes  
Version(s): prior to versions 1.0.2k, 1.1.0d
Description:   Several vulnerabilities were reported in OpenSSL. A remote user can cause the target service to crash. A remote user can obtain potentially sensitive information on the target system.

A remote user can send a specially crafted truncated packet to the target server or client running on a 32-bit host and using a specific cipher to trigger an out-of-bounds memory read error and cause the service to crash [CVE-2017-3731]. CHACHA20/POLY1305 is affected on version 1.1.0. RC4-MD5 is affected on version 1.0.2.

The vendor was notified on November 13, 2016.

Robert Swiecki of Google reported this vulnerability.

A remote server can supply specially crafted parameters for a DHE or ECDHE key exchange to trigger a null pointer dereference and cause the target client service to crash [CVE-2017-3730]. Version 1.1.0 is affected.

The vendor was notified on January 14, 2017.

Guido Vranken reported this vulnerability.

A remote user can exploit a carry propagation flaw in BN_mod_exp() to potentially determine information about the private key in certain situations [CVE-2017-3732].

Systems configured for persistent DH parameters and sharing a private key between multiple clients are affected.

The vendor was notified on January 15, 201.

The OSS-Fuzz project reported this vulnerability.

Impact:   A remote user can cause the target service to crash.

A remote user can obtain potentially sensitive information on the target system.

Solution:   FreeBSD has issued a fix for CVE-2017-3731 and CVE-2017-3732.

The FreeBSD advisory is available at:

Vendor URL: (Links to External Site)
Cause:   Access control error
Underlying OS:  UNIX (FreeBSD)
Underlying OS Comments:  10.3, 11.0

Message History:   This archive entry is a follow-up to the message listed below.
Jan 26 2017 OpenSSL Multiple Bugs Let Remote Users Deny Service and Obtain Potentially Sensitive Information

 Source Message Contents

Subject:  FreeBSD Security Advisory FreeBSD-SA-17:02.openssl

Hash: SHA512

FreeBSD-SA-17:02.openssl                                    Security Advisory
                                                          The FreeBSD Project

Topic:          OpenSSL multiple vulnerabilities

Category:       contrib
Module:         openssl
Announced:      2017-02-23
Affects:        All supported versions of FreeBSD.
Corrected:      2017-01-26 19:14:14 UTC (stable/11, 11.0-STABLE)
                2017-02-23 07:11:48 UTC (releng/11.0, 11.0-RELEASE-p8)
                2017-01-27 07:45:06 UTC (stable/10, 10.3-STABLE)
                2017-02-23 07:12:18 UTC (releng/10.3, 10.3-RELEASE-p16)
CVE Name:       CVE-2016-7055, CVE-2017-3731, CVE-2017-3732

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

If an SSL/TLS server or client is running on a 32-bit host, and a specific
cipher is being used, then a truncated packet can cause that server or
client to perform an out-of-bounds read, usually resulting in a crash.

There is a carry propagating bug in the x86_64 Montgomery squaring procedure.
No EC algorithms are affected. Analysis suggests that attacks against RSA and
DSA as a result of this defect would be very difficult to perform and are not
believed likely. Attacks against DH are considered just feasible (although
very difficult) because most of the work necessary to deduce information
about a private key may be performed offline. The amount of resources
required for such an attack would be very significant and likely only
accessible to a limited number of attackers. An attacker would additionally
need online access to an unpatched system using the target private key in
a scenario with persistent DH parameters and a private key that is shared
between multiple clients. [CVE-2017-3732]

Montgomery multiplication may produce incorrect results. [CVE-2016-7055]

III. Impact

A remote attacker may trigger a crash on servers or clients that supported
RC4-MD5. [CVE-2017-3731]

A remote attacker may be able to deduce information about a private key,
but that would require enormous amount of resources. [CVE-2017-3732,

IV.  Workaround

No workaround is available.

V.   Solution

Perform one of the following:

1) Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date.

Restart all daemons that use the library, or reboot the system.

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

Systems running a RELEASE version of FreeBSD on the i386 or amd64
platforms can be updated via the freebsd-update(8) utility:

# freebsd-update fetch
# freebsd-update install

Restart all daemons that use the library, or reboot the system.

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

The following patches have been verified to apply to the applicable
FreeBSD release branches.

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

[FreeBSD 11.0]
# fetch
# fetch
# gpg --verify openssl-11.patch.asc

[FreeBSD 10.3]
# fetch
# fetch
# gpg --verify openssl-10.patch.asc

b) Apply the patch.  Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch

c) Recompile the operating system using buildworld and installworld as
described in <URL:>.

Restart all daemons that use the library, or reboot the system.

VI.  Correction details

The following list contains the correction revision numbers for each
affected branch.

Branch/path                                                      Revision
- -------------------------------------------------------------------------
stable/10/                                                        r312863
releng/10.3/                                                      r314125
stable/11/                                                        r312826
releng/11.0/                                                      r314126
- -------------------------------------------------------------------------

To see which files were modified by a particular revision, run the
following command, replacing NNNNNN with the revision number, on a
machine with Subversion installed:

# svn diff -cNNNNNN --summarize svn://

Or visit the following URL, replacing NNNNNN with the revision number:


VII. References





The latest revision of this advisory is available at
Version: GnuPG v2.1.18 (FreeBSD)

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