ntp: ntpd accepts unauthenticated packets with symmetric key crypto
Published Apr 8, 2015
1.8
LOWCVSS 2.0
EPSS 2.24%
Description
The symmetric-key feature in the receive function in ntp_proto.c in ntpd in NTP 4.x before 4.2.8p2 requires a correct MAC only if the MAC field has a nonzero length, which makes it easier for man-in-the-middle attackers to spoof packets by omitting the MAC.
Affected products
No data.
No data.
Red Hat Enterprise Linux 6
ntp-0:4.2.6p5-5.el6
Fixed · RHSA-2015:1459
Red Hat Enterprise Linux 7
ntp-0:4.2.6p5-22.el7
Fixed · RHSA-2015:2231
Red Hat Enterprise Linux 5
ntp
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | ntp-0:4.2.6p5-5.el6 | Fixed | RHSA-2015:1459 |
| Red Hat Enterprise Linux 7 | ntp-0:4.2.6p5-22.el7 | Fixed | RHSA-2015:2231 |
| Red Hat Enterprise Linux 5 | ntp | Not affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
This issue did not affect the version of ntp as shipped with Red Hat Enterprise Linux 5
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
No CVSS v3.0 score for this CVE.
AV:A/AC:H/Au:N/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 1, 2026.
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 (10 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 2.24% (0.02243) | 82.23th | v5 (v2026.06.15) |
| Jun 15, 2026 | 2.22% (0.02219) | 80.30th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.55% (0.00554) | 66.11th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.63% (0.00634) | 79.78th | v3 (v2023.03.01) |
| May 2, 2024 | 0.63% (0.00634) | 78.87th | v3 (v2023.03.01) |
| Aug 12, 2023 | 0.80% (0.00802) | 79.50th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.57% (0.00566) | 74.41th | v3 (v2023.03.01) |
| Mar 6, 2023 | 2.69% (0.02686) | 82.85th | v2 (v2022.01.01) |
| Apr 1, 2022 | 2.69% (0.02686) | 81.17th | v2 (v2022.01.01) |
| Feb 4, 2022 | 2.69% (0.02686) | 62.66th | v2 (v2022.01.01) |
References (25)
- http://bugs.ntp.org/show_bug.cgi?id=2779 x_refsource_CONFIRM
- http://lists.apple.com/archives/security-announce/2015/Jun/msg00002.html vendor-advisoryx_refsource_APPLE
- http://lists.fedoraproject.org/pipermail/package-announce/2015-April/155863.html vendor-advisoryx_refsource_FEDORA
- http://lists.fedoraproject.org/pipermail/package-announce/2015-April/155864.html vendor-advisoryx_refsource_FEDORA
- http://lists.opensuse.org/opensuse-updates/2015-04/msg00052.html vendor-advisoryx_refsource_SUSE
- http://marc.info/?l=bugtraq&m=143213867103400&w=2 vendor-advisoryx_refsource_HP
- http://rhn.redhat.com/errata/RHSA-2015-1459.html vendor-advisoryx_refsource_REDHAT
- http://support.apple.com/kb/HT204942 x_refsource_CONFIRM
- http://support.ntp.org/bin/view/Main/SecurityNotice#Recent_Vulnerabilities x_refsource_CONFIRMVendor Advisory
- http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20150408-ntpd vendor-advisoryx_refsource_CISCO
- http://tools.cisco.com/security/center/viewAlert.x?alertId=38276 vendor-advisoryx_refsource_CISCO
- http://www.debian.org/security/2015/dsa-3223 vendor-advisoryx_refsource_DEBIAN
- http://www.kb.cert.org/vuls/id/374268 third-party-advisoryx_refsource_CERT-VNThird Party AdvisoryUS Government Resource
- http://www.mandriva.com/security/advisories?name=MDVSA-2015:202 vendor-advisoryx_refsource_MANDRIVA
- http://www.oracle.com/technetwork/topics/security/bulletinapr2015-2511959.html x_refsource_CONFIRM
- http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html x_refsource_CONFIRM
- http://www.securityfocus.com/bid/73951 vdb-entryx_refsource_BID
- http://www.securitytracker.com/id/1032032 vdb-entryx_refsource_SECTRACK
- http://www.ubuntu.com/usn/USN-2567-1 vendor-advisoryx_refsource_UBUNTU
- https://access.redhat.com/security/cve/CVE-2015-1798 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1199430 Issue Tracking
- https://kc.mcafee.com/corporate/index?page=content&id=SB10114 x_refsource_CONFIRM
- https://nvd.nist.gov/vuln/detail/CVE-2015-1798
- https://security.gentoo.org/glsa/201509-01 vendor-advisoryx_refsource_GENTOO
- https://www.cve.org/CVERecord?id=CVE-2015-1798
Change history (0)
No recorded changes yet.