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Category:   Application (VPN)  >   OpenSSL Vendors:
(FreeBSD Issues Fix) OpenSSL Multiple Bugs Let Remote Users Cause the Target Application to Crash
SecurityTracker Alert ID:  1037892
SecurityTracker URL:
CVE Reference:   CVE-2016-7055   (Links to External Site)
Date:  Feb 23 2017
Impact:   Denial of service via network
Fix Available:  Yes  Vendor Confirmed:  Yes  
Version(s): prior to 1.0.2, 1.1.0 and later
Description:   Several vulnerabilities were reported in OpenSSL. A remote user can cause the target application to crash.

A remote user can send specially crafted payloads via a TLS connection using *-CHACHA20-POLY1305 ciphersuites to trigger a heap overflow and cause OpenSSL to crash [CVE-2016-7054]. Versions 1.1.0 and later are affected.

Robert Swiecki (Google Security Team) reported this vulnerability.

A remote user can send data with specially crafted cryptographic message syntax (CMS) structures to trigger a null pointer dereference in the processing of invalid encodings in the ASN.1 'CHOICE' type and cause the application using OpenSSL to crash [CVE-2016-7053].

Tyler Nighswander of ForAllSecure reported this vulnerability.

An error may occur in a Broadwell-specific Montgomery multiplication procedure on certain length data [CVE-2016-7055]. A remote user can send specially crafted data in certain cases to trigger errors in public-key operations in configurations where multiple remote clients select an affected EC algorithm and where the target server shares a private key between the multiple clients [which is not a default configuration]. Transient authentication and key negotiation failures may also occur. Versions prior to 1.0.2 are not affected.

Richard Morgan reported this vulnerability.

Impact:   A remote user can cause the target application using OpenSSL to crash.
Solution:   FreeBSD has issued a fix for CVE-2016-7055.

The FreeBSD advisory is available at:

Vendor URL: (Links to External Site)
Cause:   Access control error, Boundary error, State error
Underlying OS:  UNIX (FreeBSD)
Underlying OS Comments:  9.3, 10.1, 10.2, 10.3, 11.0

Message History:   This archive entry is a follow-up to the message listed below.
Nov 10 2016 OpenSSL Multiple Bugs Let Remote Users Cause the Target Application to Crash

 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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