SynopsisThe remote CentOS host is missing one or more security updates.
DescriptionUpdated ntp packages that fix several security issues are now available for Red Hat Enterprise Linux 6 and 7.
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.
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.
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.
SolutionUpdate the affected ntp packages.