RHSA-2015:0104 - Security Advisory

Topic

Updated ntp packages that fix several security issues are now available for
Red Hat Enterprise Linux 6.5 Extended Update Support.

Red Hat Product Security has rated this update as having Important 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.

Description

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

Multiple buffer overflow flaws were discovered in ntpd's crypto_recv(),
ctl_putdata(), and configure() functions. A remote attacker could use
either of these flaws to send a specially crafted request packet that could
crash ntpd or, potentially, execute arbitrary code with the privileges of
the ntp user. Note: the crypto_recv() flaw requires non-default
configurations to be active, while the ctl_putdata() flaw, by default, can
only be exploited via local attackers, and the configure() flaw requires
additional authentication to exploit. (CVE-2014-9295)

It was found that ntpd automatically generated weak keys for its internal
use if no ntpdc request authentication key was specified in the ntp.conf
configuration file. A remote attacker able to match the configured IP
restrictions could guess the generated key, and possibly use it to send
ntpdc query or configuration requests. (CVE-2014-9293)

It was found that ntp-keygen used a weak method for generating MD5 keys.
This could possibly allow an attacker to guess generated MD5 keys that
could then be used to spoof an NTP client or server. Note: it is
recommended to regenerate any MD5 keys that had explicitly been generated
with ntp-keygen; the default installation does not contain such keys.
(CVE-2014-9294)

A missing return statement in the receive() function could potentially
allow a remote attacker to bypass NTP's authentication mechanism.
(CVE-2014-9296)

All ntp users are advised to upgrade to this updated package, which
contains backported patches to resolve these issues. 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.

This update is available via the Red Hat Network. Details on how to use the
Red Hat Network to apply this update are available at
https://access.redhat.com/articles/11258

Affected Products

• 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 6.5 x86_64
• 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 6.5 ppc64
• Red Hat Enterprise Linux Server - TUS 6.5 x86_64
• 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 6.5 x86_64

Fixes

• BZ - 1176032 - CVE-2014-9293 ntp: automatic generation of weak default key in config_auth()
• BZ - 1176035 - CVE-2014-9294 ntp: ntp-keygen uses weak random number generator and seed when generating MD5 keys
• BZ - 1176037 - CVE-2014-9295 ntp: Multiple buffer overflows via specially-crafted packets
• BZ - 1176040 - CVE-2014-9296 ntp: receive() missing return on error

CVEs

• CVE-2014-9294
• CVE-2014-9295
• CVE-2014-9293
• CVE-2014-9296

References

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