CVE-2015-7974

Name: CVE-2015-7974
Creator: NVD / NIST
Published: 2016-01-26T19:59:00.107+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.7/10EPSS 5.71%

Last modified Jun 17, 2026

CVE-2015-7974 is a high-severity vulnerability rated 7.7/10 on the CVSS scale. NTP 4.x before 4.2.8p6 and 4.3.x before 4.3.90 do not verify peer associations of symmetric keys when authenticating packets, which might allow remote attackers to conduct impersonation attacks via an arbitrary trusted key, aka a "skeleton key.". EPSS estimates a 5.71% chance of exploitation in the next 30 days.

Description

NTP 4.x before 4.2.8p6 and 4.3.x before 4.3.90 do not verify peer associations of symmetric keys when authenticating packets, which might allow remote attackers to conduct impersonation attacks via an arbitrary trusted key, aka a "skeleton key."

Metrics

CVSS 3.1

7.7/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

EPSS Probability

5.71%

92.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-287

Affected Software

Vendor	Product	Versions
Ntp	Ntp	>= 4.2.0, < 4.2.8
Ntp	Ntp	>= 4.3.0, < 4.3.90
Ntp	Ntp	4.2.8
Siemens	Tim 4r-Ie Firmware	All versions
Siemens	Tim 4r-Ie Dnp3 Firmware	All versions
Netapp	Clustered Data Ontap	All versions
Netapp	Oncommand Balance	All versions
Debian	Debian Linux	8.0
Debian	Debian Linux	9.0

References

http://bugs.ntp.org/show_bug.cgi?id=2936Issue Tracking, Vendor Advisory
http://rhn.redhat.com/errata/RHSA-2016-2583.htmlThird Party Advisory
http://support.ntp.org/bin/view/Main/NtpBug2936Vendor Advisory
http://www.debian.org/security/2016/dsa-3629Third Party Advisory
http://www.securityfocus.com/bid/81960Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1034782Third Party Advisory, VDB Entry
http://www.talosintel.com/reports/TALOS-2016-0071/Exploit, Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdfThird Party Advisory
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03750en_usThird Party Advisory
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03766en_usThird Party Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:09.ntp.ascThird Party Advisory
https://security.gentoo.org/glsa/201607-15Third Party Advisory
https://security.netapp.com/advisory/ntap-20171031-0001/Third Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11Third Party Advisory, US Government Resource
http://bugs.ntp.org/show_bug.cgi?id=2936Issue Tracking, Vendor Advisory
http://rhn.redhat.com/errata/RHSA-2016-2583.htmlThird Party Advisory
http://support.ntp.org/bin/view/Main/NtpBug2936Vendor Advisory
http://www.debian.org/security/2016/dsa-3629Third Party Advisory
http://www.securityfocus.com/bid/81960Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1034782Third Party Advisory, VDB Entry
http://www.talosintel.com/reports/TALOS-2016-0071/Exploit, Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdfThird Party Advisory
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03750en_usThird Party Advisory
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03766en_usThird Party Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:09.ntp.ascThird Party Advisory
https://security.gentoo.org/glsa/201607-15Third Party Advisory
https://security.netapp.com/advisory/ntap-20171031-0001/Third Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11Third Party Advisory, US Government Resource

Timeline

Published: Jan 26, 2016
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2015-7974?

How severe is CVE-2015-7974?

CVE-2015-7974 has a CVSS score of 7.7/10 (HIGH severity). The EPSS model estimates a 5.71% probability of exploitation in the next 30 days.

How do I fix CVE-2015-7974?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2015-7974?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST