ntp: Ephemeral association time spoofing additional protection
Published Mar 6, 2018
5.3
MEDIUMCVSS 3.1
EPSS 2.69%
Description
ntpd in ntp 4.2.x before 4.2.8p7 and 4.3.x before 4.3.92 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.
Affected products
No data.
Configuration 1
- ≥ 4.2.0 · < 4.2.8
- ≥ 4.3.0 · < 4.3.92
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
- 4.2.8
Configuration 2
- ≥ 1.1 · < 1.1.6-6931-3
- < 6.1.5-15254
- < 6.1.6-15266
- ≥ 5.2 · < 6.1.6-15266
Configuration 3
- < 2.2.3-1505
Configuration 5
- < c.4.2.8.4.0
No data.
Red Hat Enterprise Linux 5
ntp
Will not fix
Red Hat Enterprise Linux 6
ntp
Will not fix
Red Hat Enterprise Linux 7
ntp
Will not fix
Red Hat Enterprise Linux 8
ntp
Fix deferred
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 5 | ntp | Will not fix | n/a |
| Red Hat Enterprise Linux 6 | ntp | Will not fix | n/a |
| Red Hat Enterprise Linux 7 | ntp | Will not fix | n/a |
| Red Hat Enterprise Linux 8 | ntp | Fix deferred | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
AV:N/AC:M/Au:S/C:N/I:P/A:N
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 2, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
- EPSS v4
Percentile over time
- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
- EPSS v4
Table of values (17 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 2, 2026 | 2.69% (0.02686) | 85.34th | v5 (v2026.06.15) |
| Jun 15, 2026 | 2.76% (0.02759) | 84.29th | v5 (v2026.06.15) |
| Dec 14, 2025 | 0.56% (0.00563) | 67.61th | v4 (v2025.03.14) |
| Nov 18, 2025 | 1.66% (0.01660) | 80.55th | v4 (v2025.03.14) |
| Aug 18, 2025 | 0.52% (0.00518) | 65.75th | v4 (v2025.03.14) |
| Jul 13, 2025 | 2.06% (0.02063) | 83.14th | v4 (v2025.03.14) |
| Mar 30, 2025 | 0.97% (0.00969) | 74.58th | v4 (v2025.03.14) |
| Mar 29, 2025 | 2.25% (0.02253) | 74.26th | v4 (v2025.03.14) |
| Mar 17, 2025 | 0.97% (0.00969) | 75.04th | v4 (v2025.03.14) |
| Dec 17, 2024 | 1.20% (0.01198) | 84.88th | v3 (v2023.03.01) |
| Dec 12, 2024 | 0.14% (0.00144) | 51.85th | v3 (v2023.03.01) |
| Sep 3, 2023 | 0.14% (0.00144) | 49.65th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.18% (0.00185) | 54.03th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.28% (0.01282) | 68.34th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.28% (0.01282) | 41.72th | v2 (v2022.01.01) |
| Feb 3, 2022 | 2.27% (0.02273) | 50.89th | v5 (v2026.06.15) |
| Apr 14, 2021 | 2.27% (0.02273) | 0.00th | v1 |
No CWE recorded.
References (13)
- http://packetstormsecurity.com/files/146631/Slackware-Security-Advisory-ntp-Updates.html x_refsource_MISCThird Party AdvisoryVDB Entry
- http://support.ntp.org/bin/view/Main/NtpBug3415 x_refsource_CONFIRMThird Party Advisory
- http://www.securityfocus.com/archive/1/541824/100/0/threaded mailing-listx_refsource_BUGTRAQThird Party AdvisoryVDB Entry
- http://www.securityfocus.com/bid/103194 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- https://access.redhat.com/security/cve/CVE-2018-7170 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1550214 x_refsource_MISCIssue TrackingThird Party Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2018-7170
- https://security.FreeBSD.org/advisories/FreeBSD-SA-18:02.ntp.asc vendor-advisoryx_refsource_FREEBSDThird Party Advisory
- https://security.gentoo.org/glsa/201805-12 vendor-advisoryx_refsource_GENTOOThird Party Advisory
- https://security.netapp.com/advisory/ntap-20180626-0001/ x_refsource_CONFIRMThird Party Advisory
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03962en_us x_refsource_CONFIRMThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2018-7170
- https://www.synology.com/support/security/Synology_SA_18_13 x_refsource_CONFIRMThird Party Advisory
Change history (0)
No recorded changes yet.