CVE-2015-7973
ntp: replay attack on authenticated broadcast mode
Severity
ModerateRed Hat Product Security
CVSS 2.0
Review impact separately from score.
Published · January 20, 2016
Updated · May 13, 2026
Description
NTP before 4.2.8p6 and 4.3.x before 4.3.90, when configured in broadcast mode, allows man-in-the-middle attackers to conduct replay attacks by sniffing the network.
Statement
This issue affects the versions of ntp as shipped with Red Hat Enterprise Linux 5, 6, and 7. Red Hat Product Security has rated this issue as having Moderate security impact. A future update may address this issue in Red Hat Enterprise Linux 6 and 7. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Do not use NTP's broadcast mode by not configuring the "broadcast" directive in the ntp.conf file.
CVSS / CWE
CVSS 2.0 · 4.3AV:A/AC:M/Au:N/C:N/I:P/A:P
CWE-294 · Authentication Bypass by Capture-replay