As per upstream NTP security advisory: Code in ntp_proto.c:receive() was missing a 'return;' in the code path where an error was detected, which meant processing did not stop when a specific rare error occurred. We haven't found a way for this bug to affect system integrity. If there is no way to affect system integrity the base CVSS score for this bug is 0. If there is one avenue through which system integrity can be partially affected, the base score becomes a 5. If system integrity can be partially affected via all three integrity metrics, the CVSS base score become 7.5. This vulnerability was discovered by Stephen Roettger of the Google Security Team. Mitigation: Remove or comment out all configuration directives beginning with the crypto keyword in your ntp.conf file.
Upstream change to the NEWS file with details quoted in comment 0: http://bk1.ntp.org/ntp-dev/?PAGE=patch&REV=5493dc3dofY6drKJde9W-5O1M3s4eg Upstream bug: http://bugs.ntp.org/show_bug.cgi?id=2670 Upstream commit: http://bk1.ntp.org/ntp-dev/?PAGE=patch&REV=548ad06feXHK1HlZoY-WZVyynwvwAg
External References: https://access.redhat.com/articles/1305723 http://support.ntp.org/bin/view/Main/SecurityNotice#receive_missing_return_on_error
Created ntp tracking bugs for this issue: Affects: fedora-all [bug 1176191]
This issue has been addressed in the following products: Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 7 Via RHSA-2014:2024 https://rhn.redhat.com/errata/RHSA-2014-2024.html
ntp-4.2.6p5-19.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.
ntp-4.2.6p5-25.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.
ntp-4.2.6p5-13.fc19 has been pushed to the Fedora 19 stable repository. If problems still persist, please make note of it in this bug report.
Statement: This issue did not affect the versions of ntpd as shipped with Red Hat Enterprise Linux 4 and 5. It has been addressed in Red Hat Enterprise Linux 6 and 7 via RHSA-2014:2024.
This issue has been addressed in the following products: Red Hat Enterprise Linux 6.5 EUS - Server and Compute Node Only Via RHSA-2015:0104 https://rhn.redhat.com/errata/RHSA-2015-0104.html