ntpd in ntp 4.2.x before 4.2.8p7 allows authenticated users that know the private symmetric key to create arbitrarily-many ephemeral associations in order to win the clock selection of ntpd and modify a victim's clock via a Sybil attack. This issue exists because of an incomplete fix for CVE-2016-1549 __.(CVE-2018-7170 __)
The ntpq and ntpdc command-line utilities that are part of ntp package are vulnerable to stack-based buffer overflow via crafted hostname. Applications using these vulnerable utilities with an untrusted input may be potentially exploited, resulting in a crash or arbitrary code execution under privileges of that application.(CVE-2018-12327 __)
Run yum update ntp to update your system.
i686: ntpdate-4.2.8p12-1.39.amzn1.i686 ntp-4.2.8p12-1.39.amzn1.i686 ntp-debuginfo-4.2.8p12-1.39.amzn1.i686 noarch: ntp-perl-4.2.8p12-1.39.amzn1.noarch ntp-doc-4.2.8p12-1.39.amzn1.noarch src: ntp-4.2.8p12-1.39.amzn1.src x86_64: ntp-debuginfo-4.2.8p12-1.39.amzn1.x86_64 ntp-4.2.8p12-1.39.amzn1.x86_64 ntpdate-4.2.8p12-1.39.amzn1.x86_64