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Posted on 23 February 2017
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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:https://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
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.
[CVE-2017-3731]
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,
CVE-2016-7055]
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 https://security.FreeBSD.org/patches/SA-17:02/openssl-11.patch
# fetch https://security.FreeBSD.org/patches/SA-17:02/openssl-11.patch.asc
# gpg --verify openssl-11.patch.asc
[FreeBSD 10.3]
# fetch https://security.FreeBSD.org/patches/SA-17:02/openssl-10.patch
# fetch https://security.FreeBSD.org/patches/SA-17:02/openssl-10.patch.asc
# 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:https://www.FreeBSD.org/handbook/makeworld.html>.
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://svn.freebsd.org/base
Or visit the following URL, replacing NNNNNN with the revision number:
<URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>
VII. References
<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-7055>
<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3731>
<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-3732>
<URL:https://www.openssl.org/news/secadv/20170126.txt>
The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-17:02.openssl.asc>
