ntp-keygen in ntp 4.2.8px before 4.2.8p2-RC2 and 4.3.x before 4.3.12 does not generate MD5 keys with sufficient entropy on big endian machines when the lowest order byte of the temp variable is between 0x20 and 0x7f and not #, which might allow remote attackers to obtain the value of generated MD5 keys via a brute force attack with the 93 possible keys.
https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03886en_us
https://bugzilla.redhat.com/show_bug.cgi?id=1210324
https://bugs.ntp.org/show_bug.cgi?id=2797
http://www.securityfocus.com/bid/74045
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
http://www.oracle.com/technetwork/topics/security/bulletinapr2015-2511959.html
http://www.openwall.com/lists/oss-security/2015/04/23/14
http://www.debian.org/security/2015/dsa-3388
http://www.debian.org/security/2015/dsa-3223
http://rhn.redhat.com/errata/RHSA-2015-2231.html
http://rhn.redhat.com/errata/RHSA-2015-1459.html
http://lists.opensuse.org/opensuse-security-announce/2015-07/msg00000.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-April/156248.html
http://bk1.ntp.org/ntp-stable/?PAGE=patch&REV=55199296N2gFqH1Hm5GOnhrk9Ypygg