2016 m. kovo 16 d., trečiadienis

FreeBSD Security Advisory FreeBSD-SA-16:13.bind

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FreeBSD-SA-16:13.bind                                       Security Advisory
                                                          The FreeBSD Project

Topic:          Multiple BIND vulnerabilities

Category:       contrib
Module:         bind
Announced:      2016-03-10
Credits:        ISC
Affects:        FreeBSD 9.x
Corrected:      2016-03-10 07:47:55 UTC (stable/9, 9.3-STABLE)
                2016-03-10 10:03:28 UTC (releng/9.3, 9.3-RELEASE-p38)
CVE Name:       CVE-2016-1285, CVE-2016-1286

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

BIND 9 is an implementation of the Domain Name System (DNS) protocols.
The named(8) daemon is an Internet Domain Name Server.

II.  Problem Description

Testing by ISC has uncovered a defect in control channel input handling
which can cause named to exit due to an assertion failure in sexpr.c
or alist.c when a malformed packet is sent to named's control channel
(the interface which allows named to be controlled using the "rndc"
server control utility). [CVE-2016-1285]

An error when parsing signature records for DNAME records having specific
properties can lead to named exiting due to an assertion failure in
resolver.c or db.c. [CVE-2016-1286]

III. Impact

A remote attacker can deliberately trigger the failed assertion if the
DNS server accepts remote rndc commands regardless if authentication
is configured.  Note that this is not enabled by default. [CVE-2016-1285]

A remote attacker who can cause a server to make a query deliberately
chosen to generate a response containing a signature record which
would trigger a failed assertion and cause named to stop.  Disabling
DNSsec does not provide protection against this vulnerability.
[CVE-2016-1286]

IV.  Workaround

No workaround is available, but hosts not running named(8) are not
vulnerable.

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.

The named service has to be restarted after the update.  A reboot is
recommended but not required.

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

The named service has to be restarted after the update.  A reboot is
recommended but not required.

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.

# fetch https://security.FreeBSD.org/patches/SA-16:13/bind.patch
# fetch https://security.FreeBSD.org/patches/SA-16:13/bind.patch.asc
# gpg --verify bind.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 the named(8) daemon, or reboot the system.

VI.  Correction details

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

Branch/path                                                      Revision
- -------------------------------------------------------------------------
stable/9/                                                         r296608
releng/9.3/                                                       r296611
- -------------------------------------------------------------------------

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://kb.isc.org/article/AA-01352>

<URL:https://kb.isc.org/article/AA-01353>

<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-1285>

<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-1286>

The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-16:13.bind.asc>

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