RHSA-2015:2520 - Security Advisory

Topic

Updated ntp packages that fix one security issue are now available for Red
Hat Enterprise Linux 6.5 and 6.6 Extended Update Support.

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

Description

The Network Time Protocol (NTP) is used to synchronize a computer's time
with a referenced time source.

It was discovered that ntpd as a client did not correctly check timestamps
in Kiss-of-Death packets. A remote attacker could use this flaw to send a
crafted Kiss-of-Death packet to an ntpd client that would increase the
client's polling interval value, and effectively disable synchronization
with the server. (CVE-2015-7704)

Red Hat would like to thank Aanchal Malhotra, Isaac E. Cohen, and Sharon
Goldberg of Boston University for reporting this issue.

All ntp users are advised to upgrade to these updated packages, which
contain a backported patch to resolve this issue. After installing the
update, the ntpd daemon will restart automatically.

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

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 i386
• Red Hat Enterprise Linux Server - AUS 6.6 x86_64
• Red Hat Enterprise Linux Server - AUS 6.5 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.5 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.5 ppc64
• Red Hat Enterprise Linux Server - TUS 6.6 x86_64
• Red Hat Enterprise Linux Server - TUS 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.6 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.6 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 i386
• Red Hat Enterprise Linux EUS Compute Node 6.6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 6.5 x86_64

Fixes

• BZ - 1271070 - CVE-2015-7704 ntp: disabling synchronization via crafted KoD packet

CVEs

• CVE-2015-7704

References

• https://access.redhat.com/security/updates/classification/#important