Red Hat Enterprise Linux 6 & 7: RHSA-2014:2024-01 Important NTP Flaws

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.