Scientific Linux SL6.x, SL7.x Advisory 2016:1141-1 Moderate: ntp DoS

Date: Thu, 16 Jun 2016 21:14:14 -0000
Reply-To: scientific-linux-users@
Sender: Security Errata for Scientific Linux
 
From: Kevin Hill 
Subject: Security ERRATA Moderate: ntp on SL6.x, SL7.x i386/x86_64
MIME-Version: 1.0
Message-ID: <20160616211414.27375.60336@slpackages.fnal.gov>

Synopsis: Moderate: ntp security update
Advisory ID: SLSA-2016:1141-1
Issue Date: 2016-05-31
CVE Numbers: CVE-2015-7979
 CVE-2016-1547
 CVE-2016-1548
 CVE-2016-1550
 CVE-2016-2518
--

Security Fix(es):

* It was found that when NTP was configured in broadcast mode, a remote
attacker could broadcast packets with bad authentication to all clients.
The clients, upon receiving the malformed packets, would break the
association with the broadcast server, causing them to become out of sync
over a longer period of time. (CVE-2015-7979)

* A denial of service flaw was found in the way NTP handled preemptable
client associations. A remote attacker could send several crypto NAK
packets to a victim client, each with a spoofed source address of an
existing associated peer, preventing that client from synchronizing its
time. (CVE-2016-1547)

* It was found that an ntpd client could be forced to change from basic
client/server mode to the interleaved symmetric mode. A remote attacker
could use a spoofed packet that, when processed by an ntpd client, would
cause that client to reject all future legitimate server responses,
effectively disabling time synchronization on that client. (CVE-2016-1548)

* A flaw was found in the way NTP's libntp performed message
authentication. An attacker able to observe the timing of the comparison
function used in packet authentication could potentially use this flaw to
recover the message digest. (CVE-2016-1550)

* An out-of-bounds access flaw was found in the way ntpd processed certain
packets. An authenticated attacker could use a crafted packet to create a
peer association with hmode of 7 and larger, which could potentially
(although highly unlikely) cause ntpd to crash. (CVE-2016-2518)

The CVE-2016-1548 issue was discovered by Miroslav Lichvar (Red Hat).
--

SL6
 x86_64
 ntp-4.2.6p5-10.el6.1.x86_64.rpm
 ntp-debuginfo-4.2.6p5-10.el6.1.x86_64.rpm
 ntpdate-4.2.6p5-10.el6.1.x86_64.rpm
 ntp-perl-4.2.6p5-10.el6.1.x86_64.rpm
 i386
 ntp-4.2.6p5-10.el6.1.i686.rpm
 ntp-debuginfo-4.2.6p5-10.el6.1.i686.rpm
 ntpdate-4.2.6p5-10.el6.1.i686.rpm
 ntp-perl-4.2.6p5-10.el6.1.i686.rpm
 noarch
 ntp-doc-4.2.6p5-10.el6.1.noarch.rpm
SL7
 x86_64
 ntp-4.2.6p5-22.el7_2.2.x86_64.rpm
 ntp-debuginfo-4.2.6p5-22.el7_2.2.x86_64.rpm
 ntpdate-4.2.6p5-22.el7_2.2.x86_64.rpm
 sntp-4.2.6p5-22.el7_2.2.x86_64.rpm
 noarch
 ntp-doc-4.2.6p5-22.el7_2.2.noarch.rpm
 ntp-perl-4.2.6p5-22.el7_2.2.noarch.rpm

- Scientific Linux Development Team