7.1 - RHSA-2017:0252

Problem Description:

An update for ntp is now available for Red Hat Enterprise Linux 6 and Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Client (v. 7) - x86_64 Red Hat Enterprise Linux Client Optional (v. 7) - noarch, x86_64 Red Hat Enterprise Linux ComputeNode (v. 7) - x86_64 Red Hat Enterprise Linux ComputeNode Optional (v. 7) - noarch, x86_64 Red Hat Enterprise Linux Desktop (v. 6) - i386, x86_64 Red Hat Enterprise Linux Desktop Optional (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux HPC Node (v. 6) - x86_64 Red Hat Enterprise Linux HPC Node Optional (v. 6) - noarch, x86_64 Red Hat Enterprise Linux Server (v. 6) - i386, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server (v. 7) - aarch64, ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 6) - i386, noarch, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 7) - aarch64, noarch, ppc64, ppc64le, s390x, x86_64 Red Hat Enterprise Linux Workstation (v. 6) - i386, x86_64 Red Hat Enterprise Linux Workstation (v. 7) - x86_64 Red Hat Enterprise Linux Workstation Optional (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 7) - noarch, x86_64

3. Description:

The Network Time Protocol (NTP) is used to synchronize a computer's time with another referenced time source. These packages include the ntpd service which continuously adjusts system time and utilities used to query and configure the ntpd service.

Security Fix(es):

* It was found that when ntp is configured with rate limiting for all associations the limits are also applied to responses received from its configured sources. A remote attacker who knows the sources can cause a denial of service by preventing ntpd from accepting valid responses from its sources. (CVE-2016-7426)

* A flaw was found in the control mode functionality of ntpd. A remote attacker could send a crafted control mode packet which could lead to information disclosure or result in DDoS amplification attacks. (CVE-2016-9310)

* A flaw was found in the way ntpd implemented the trap service. A remote attacker could send a specially crafted packet to cause a null pointer dereference that will crash ntpd, resulting in a denial of service. (CVE-2016-9311)

* A flaw was found in the way ntpd running on a host with multiple network interfaces handled certain server responses. A remote attacker could use this flaw which would cause ntpd to not synchronize with the source. (CVE-2016-7429)

* A flaw was found in the way ntpd calculated the root delay. A remote attacker could send a specially-crafted spoofed packet to cause denial of service or in some special cases even crash. (CVE-2016-7433)

4. Solution:

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing this update, the ntpd daemon will restart automatically.

5. Bugs fixed (https://bugzilla.redhat.com/):

1397319 - CVE-2016-9310 ntp: Mode 6 unauthenticated trap information disclosure and DDoS vector 1397341 - CVE-2016-7429 ntp: Attack on interface selection 1397345 - CVE-2016-7426 ntp: Client rate limiting and server responses 1397347 - CVE-2016-7433 ntp: Broken initial sync calculations regression 1398350 - CVE-2016-9311 ntp: Null pointer dereference when trap service is enabled