[RHSA-2015:2241-03] Moderate: chrony security, bug fix, and enhancement update

[news 28]

-----BEGIN PGP SIGNED MESSAGE-----

Hash: SHA1

 

=====================================================================

Red Hat Security Advisory

 

Synopsis: Moderate: chrony security, bug fix, and enhancement update

Advisory ID: RHSA-2015:2241-03

Product: Red Hat Enterprise Linux

Advisory URL: https://rhn.redhat.com/errata/RHSA-2015-2241.html

Issue date: 2015-11-19

CVE Names: CVE-2015-1821 CVE-2015-1822 CVE-2015-1853

=====================================================================

 

1. Summary:

 

Updated chrony packages that fix three security issues, several bugs, and

add various enhancements are now available for Red Hat Enterprise Linux 7.

 

Red Hat Product Security has rated this update as having Moderate security

impact. Common Vulnerability Scoring System (CVSS) base scores, which give

detailed severity ratings, are available for each vulnerability from the

CVE links in the References section.

 

2. Relevant releases/architectures:

 

Red Hat Enterprise Linux Client (v. 7) - x86_64

Red Hat Enterprise Linux ComputeNode (v. 7) - x86_64

Red Hat Enterprise Linux Server (v. 7) - aarch64, ppc64, ppc64le, s390x, x86_64

Red Hat Enterprise Linux Workstation (v. 7) - x86_64

 

3. Description:

 

The chrony suite, chronyd and chronyc, is an advanced implementation of the

Network Time Protocol (NTP), specially designed to support systems with

intermittent connections. It can synchronize the system clock with NTP

servers, hardware reference clocks, and manual input. It can also operate

as an NTPv4 (RFC 5905) server or peer to provide a time service to other

computers in the network.

 

An out-of-bounds write flaw was found in the way chrony stored certain

addresses when configuring NTP or cmdmon access. An attacker that has the

command key and is allowed to access cmdmon (only localhost is allowed by

default) could use this flaw to crash chronyd or, possibly, execute

arbitrary code with the privileges of the chronyd process. (CVE-2015-1821)

 

An uninitialized pointer use flaw was found when allocating memory to save

unacknowledged replies to authenticated command requests. An attacker that

has the command key and is allowed to access cmdmon (only localhost is

allowed by default) could use this flaw to crash chronyd or, possibly,

execute arbitrary code with the privileges of the chronyd process.

(CVE-2015-1822)

 

A denial of service flaw was found in the way chrony hosts that were

peering with each other authenticated themselves before up[censored] their

internal state variables. An attacker could send packets to one peer host,

which could cascade to other peers, and stop the synchronization process

among the reached peers. (CVE-2015-1853)

 

These issues were discovered by Miroslav Lichvár of Red Hat.

 

The chrony packages have been upgraded to upstream version 2.1.1, which

provides a number of bug fixes and enhancements over the previous version.

Notable enhancements include:

 

* Updated to NTP version 4 (RFC 5905)

 

* Added pool directive to specify pool of NTP servers

 

* Added leapsecmode directive to select how to correct clock for leap

second

 

* Added smoothtime directive to smooth served time and enable leap smear

 

* Added asynchronous name resolving with POSIX threads

 

* Ready for year 2036 (next NTP era)

 

* Improved clock control

 

* Networking code reworked to open separate client sockets for each NTP

server

 

(BZ#1117882)

 

This update also fixes the following bug:

 

* The chronyd service previously assumed that network interfaces specified

with the "bindaddress" directive were ready when the service was started.

This could cause chronyd to fail to bind an NTP server socket to the

interface if the interface was not ready. With this update, chronyd uses

the IP_FREEBIND socket option, enabling it to bind to an interface later,

not only when the service starts. (BZ#1169353)

 

In addition, this update adds the following enhancement:

 

* The chronyd service now supports four modes of handling leap seconds,

configured using the "leapsecmode" option. The clock can be either stepped

by the kernel (the default "system" mode), stepped by chronyd ("step"

mode), slowly adjusted by slewing ("slew" mode), or the leap second can be

ignored and corrected later in normal operation ("ignore" mode). If you

select slewing, the correction will always start at 00:00:00 UTC and will

be applied at a rate specified in the "maxslewrate" option. (BZ#1206504)

 

All chrony users are advised to upgrade to these updated packages, which

correct these issues and add these enhancements.

 

4. Solution:

 

Before applying this update, make sure all previously released errata

relevant to your system have been applied.

 

For details on how to apply this update, refer to:

 

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

 

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

 

1117882 - rebase chrony to 2.1.1

1169353 - Chronyd not starting with bindaddress option set to bond interface

1206504 - RFE: option to correct clock for leap second by slewing

1209568 - RFE: add option for leap smear

1209572 - CVE-2015-1853 chrony: authentication doesn't protect symmetric associations against DoS attacks

1209631 - CVE-2015-1821 chrony: Heap out of bound write in address filter

1209632 - CVE-2015-1822 chrony: uninitialized pointer in cmdmon reply slots

1211600 - RFE: add support for SRV _ntp._udp resolution

1219492 - Use iburst option for NTP servers from DHCP

 

6. Package List:

 

Red Hat Enterprise Linux Client (v. 7):

 

Source:

chrony-2.1.1-1.el7.src.rpm

 

x86_64:

chrony-2.1.1-1.el7.x86_64.rpm

chrony-debuginfo-2.1.1-1.el7.x86_64.rpm

 

Red Hat Enterprise Linux ComputeNode (v. 7):

 

Source:

chrony-2.1.1-1.el7.src.rpm

 

x86_64:

chrony-2.1.1-1.el7.x86_64.rpm

chrony-debuginfo-2.1.1-1.el7.x86_64.rpm

 

Red Hat Enterprise Linux Server (v. 7):

 

Source:

chrony-2.1.1-1.el7.src.rpm

 

aarch64:

chrony-2.1.1-1.el7.aarch64.rpm

chrony-debuginfo-2.1.1-1.el7.aarch64.rpm

 

ppc64:

chrony-2.1.1-1.el7.ppc64.rpm

chrony-debuginfo-2.1.1-1.el7.ppc64.rpm

 

ppc64le:

chrony-2.1.1-1.el7.ppc64le.rpm

chrony-debuginfo-2.1.1-1.el7.ppc64le.rpm

 

s390x:

chrony-2.1.1-1.el7.s390x.rpm

chrony-debuginfo-2.1.1-1.el7.s390x.rpm

 

x86_64:

chrony-2.1.1-1.el7.x86_64.rpm

chrony-debuginfo-2.1.1-1.el7.x86_64.rpm

 

Red Hat Enterprise Linux Workstation (v. 7):

 

Source:

chrony-2.1.1-1.el7.src.rpm

 

x86_64:

chrony-2.1.1-1.el7.x86_64.rpm

chrony-debuginfo-2.1.1-1.el7.x86_64.rpm

 

These packages are GPG signed by Red Hat for security. Our key and

details on how to verify the signature are available from

https://access.redhat.com/security/team/key/

 

7. References:

 

https://access.redhat.com/security/cve/CVE-2015-1821

https://access.redhat.com/security/cve/CVE-2015-1822

https://access.redhat.com/security/cve/CVE-2015-1853

https://access.redhat.com/security/updates/classification/#moderate

 

8. Contact:

 

The Red Hat security contact is . More contact

details at https://access.redhat.com/security/team/contact/

 

Copyright 2015 Red Hat, Inc.

-----BEGIN PGP SIGNATURE-----

Version: GnuPG v1

 

iD8DBQFWTkF2XlSAg2UNWIIRAtUhAJ9VLqWZCrDEOFZAG5EROQf+FH02MwCfcP3l

cqxZgb5BDquCIrAAy6riOZQ=

=u/rC

-----END PGP SIGNATURE-----

 

--