Bug 1550220 (CVE-2018-7185) - CVE-2018-7185 ntp: Unauthenticated packet can reset authenticated interleaved association
Summary: CVE-2018-7185 ntp: Unauthenticated packet can reset authenticated interleaved...
Alias: CVE-2018-7185
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1550228 1550229 1562055 1582245
Blocks: 1550226 1658223
TreeView+ depends on / blocked
Reported: 2018-02-28 19:44 UTC by Pedro Sampaio
Modified: 2021-10-21 19:57 UTC (History)
7 users (show)

Fixed In Version: ntp 4.2.8p11
Doc Type: If docs needed, set a value
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Clone Of:
Last Closed: 2021-10-21 19:57:10 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Knowledge Base (Solution) 3451911 0 None None None 2018-05-21 02:21:54 UTC

Description Pedro Sampaio 2018-02-28 19:44:12 UTC
The NTP Protocol allows for both non-authenticated and authenticated associations, in client/server, symmetric (peer), and several broadcast modes. In addition to the basic NTP operational modes, symmetric mode and broadcast servers can support an interleaved mode of operation. In ntp-4.2.8p4 a bug was inadvertently introduced into the protocol engine that allows a non-authenticated zero-origin (reset) packet to reset an authenticated interleaved peer association. If an attacker can send a packet with a zero-origin timestamp and the source IP address of the "other side" of an interleaved association, the 'victim' ntpd will reset its association. The attacker must continue sending these packets in order to maintain the disruption of the association. In ntp-4.0.0 thru ntp-4.2.8p6, interleave mode could be entered dynamically. As of ntp-4.2.8p7, interleaved mode must be explicitly configured/enabled.



Comment 1 Pedro Sampaio 2018-02-28 19:51:57 UTC
Created ntp tracking bugs for this issue:

Affects: fedora-all [bug 1550228]

Comment 5 Pedro Sampaio 2019-09-19 15:11:30 UTC
External References:


Comment 6 Pedro Sampaio 2019-09-19 15:11:33 UTC

Remove the "xleave" option from the "peer HOST xleave" lines in your ntp.conf if it exists, to entirely disable interleaved mode.

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