CRITICAL
ntp: denial of service by trigerring rate limiting on NTP server
Published Aug 7, 2017
9.8
CRITICALCVSS 3.1
EPSS 12.35%
Description
The rate limiting feature in NTP 4.x before 4.2.8p4 and 4.3.x before 4.3.77 allows remote attackers to have unspecified impact via a large number of crafted requests.
Affected products
No data.
Configuration 1
OR
- ≥ 4.2.0 · < 4.2.8
- ≥ 4.3.0 · < 4.3.77
- 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
OR
- n/a
- n/a
- n/a
- n/a
Configuration 3
Configuration 4
AND
- n/a
Configuration 5
AND
- n/a
Running on/with
- n/a
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
| 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 |
No package ranges for this CVE.
Remediation
Red Hat mitigation
Do not add the "limited" configuration option to any restrict lines in the ntp.conf file.
Metrics
No CVSS v4.0 score for this CVE.
9.8 CRITICAL NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact High
Integrity Impact High
Availability Impact High
No CVSS v3.0 score for this CVE.
7.5 HIGH NVD
AV:N/AC:L/Au:N/C:P/I:P/A:P
Access Vector Network
Access Complexity Low
Authentication None
Confidentiality Impact Partial
Integrity Impact Partial
Availability Impact Partial
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
12.35% 0.12351
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
EPSS probability 0.12351
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (23 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 12.35% (0.12351) | 96.08th | v5 (v2026.06.15) |
| Jun 15, 2026 | 12.35% (0.12351) | 95.67th | v5 (v2026.06.15) |
| May 21, 2026 | 17.37% (0.17370) | 95.14th | v4 (v2025.03.14) |
| Jan 30, 2026 | 31.03% (0.31029) | 96.61th | v4 (v2025.03.14) |
| Dec 28, 2025 | 26.02% (0.26017) | 96.10th | v4 (v2025.03.14) |
| Dec 27, 2025 | 25.00% (0.24996) | 96.00th | v4 (v2025.03.14) |
| Dec 14, 2025 | 26.02% (0.26017) | 96.09th | v4 (v2025.03.14) |
| Dec 13, 2025 | 28.18% (0.28180) | 96.31th | v4 (v2025.03.14) |
| Sep 16, 2025 | 25.48% (0.25479) | 96.02th | v4 (v2025.03.14) |
| Aug 10, 2025 | 29.58% (0.29576) | 96.43th | v4 (v2025.03.14) |
| Jul 13, 2025 | 25.68% (0.25676) | 95.99th | v4 (v2025.03.14) |
| Jun 25, 2025 | 34.88% (0.34885) | 96.82th | v4 (v2025.03.14) |
| Mar 30, 2025 | 36.49% (0.36495) | 96.80th | v4 (v2025.03.14) |
| Mar 29, 2025 | 46.05% (0.46045) | 96.51th | v4 (v2025.03.14) |
| Mar 19, 2025 | 36.49% (0.36495) | 96.65th | v4 (v2025.03.14) |
| Mar 17, 2025 | 41.48% (0.41478) | 97.09th | v4 (v2025.03.14) |
| Dec 17, 2024 | 3.91% (0.03914) | 91.88th | v3 (v2023.03.01) |
| Dec 12, 2024 | 1.71% (0.01715) | 88.31th | v3 (v2023.03.01) |
| Nov 11, 2023 | 1.22% (0.01216) | 83.69th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.98% (0.00981) | 81.12th | v3 (v2023.03.01) |
| Mar 6, 2023 | 4.36% (0.04358) | 88.02th | v2 (v2022.01.01) |
| Apr 1, 2022 | 4.36% (0.04358) | 86.83th | v2 (v2022.01.01) |
| Feb 4, 2022 | 4.36% (0.04358) | 70.59th | v2 (v2022.01.01) |
Weaknesses (1)
References (39)
- http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00020.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00034.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00037.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00048.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00052.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00001.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00020.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-07/msg00026.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00042.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-updates/2015-11/msg00093.html vendor-advisoryx_refsource_SUSE
- http://lists.opensuse.org/opensuse-updates/2016-05/msg00114.html vendor-advisoryx_refsource_SUSE
- http://packetstormsecurity.com/files/134137/Slackware-Security-Advisory-ntp-Updates.html x_refsource_MISC
- http://support.ntp.org/bin/view/Main/NtpBug2901 x_refsource_CONFIRMVendor Advisory
- http://support.ntp.org/bin/view/Main/SecurityNotice#October_2015_NTP_4_2_8p4_Securit x_refsource_CONFIRMRelease NotesVendor Advisory
- http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151021-ntp vendor-advisoryx_refsource_CISCO
- http://www.securityfocus.com/archive/1/536737/100/0/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/archive/1/536796/100/0/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/archive/1/archive/1/536737/100/100/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/archive/1/archive/1/536796/100/100/threaded mailing-listx_refsource_BUGTRAQ
- http://www.securityfocus.com/bid/77284 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- http://www.securitytracker.com/id/1033951 vdb-entryx_refsource_SECTRACKThird Party AdvisoryVDB Entry
- http://www.ubuntu.com/usn/USN-2783-1 vendor-advisoryx_refsource_UBUNTU
- https://access.redhat.com/security/cve/CVE-2015-7705 Vendor Advisory
- https://bto.bluecoat.com/security-advisory/sa103 x_refsource_CONFIRM
- https://bugzilla.redhat.com/show_bug.cgi?id=1274184 x_refsource_CONFIRMIssue TrackingThird Party AdvisoryVDB Entry
- https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf x_refsource_CONFIRM
- https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf x_refsource_CONFIRMThird Party Advisory
- https://eprint.iacr.org/2015/1020.pdf x_refsource_MISCTechnical Description
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05270839 x_refsource_CONFIRMThird Party AdvisoryVDB Entry
- https://nvd.nist.gov/vuln/detail/CVE-2015-7705
- https://security.gentoo.org/glsa/201607-15 vendor-advisoryx_refsource_GENTOOThird Party AdvisoryVDB Entry
- https://security.netapp.com/advisory/ntap-20171004-0001/ x_refsource_CONFIRMThird Party Advisory
- https://support.citrix.com/article/CTX220112 x_refsource_CONFIRMThird Party Advisory
- https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11 x_refsource_MISCThird Party AdvisoryUS Government Resource
- https://us-cert.cisa.gov/ics/advisories/icsa-21-159-11 x_refsource_MISC
- https://www.arista.com/en/support/advisories-notices/security-advisories/1212-security-advisory-0016 x_refsource_MISC
- https://www.cs.bu.edu/~goldbe/NTPattack.html x_refsource_MISCNot Applicable
- https://www.cve.org/CVERecord?id=CVE-2015-7705
- https://www.kb.cert.org/vuls/id/718152 third-party-advisoryx_refsource_CERT-VNThird Party AdvisoryUS Government Resource
Change history (0)
No recorded changes yet.
Sources
CVE.org / MITRE
Status PUBLISHED
Assigner mitre
Published Aug 7, 2017
Updated Aug 6, 2024
Reserved Oct 4, 2015
Link CVE-2015-7705
CISA Vulnrichment
Updated n/a