Description
An attacker can spoof a packet from a legitimate ntpd server with an origin timestamp that matches the peer->dst timestamp recorded for that server. After making this switch, the client in NTP 4.2.8p4 and earlier and NTPSec aa48d001683e5b791a743ec9c575aaf7d867a2b0c will reject all future legitimate server responses. It is possible to force the victim client to move time after the mode has been changed. ntpq gives no indication that the mode has been switched.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| NTP Project | NTP | 4.2.8p4 | — |
| NTPsec Project | NTPSec | aa48d001683e5b791a743ec9c575aaf7d867a2b0c | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 11 | ntp | 1:4.2.8p7+dfsg-1 | — |
| Debian 8 | ntp | 1:4.2.6.p5+dfsg-7+deb8u2 | DSA-3629-1 |
| Debian 7 | ntp | 1:4.2.6.p5+dfsg-2+deb7u7 | DLA-559-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | ntp | 1:4.2.8p4+dfsg-3ubuntu5.3 | USN-3096-1 |
| Ubuntu 14.04 LTS | ntp | 1:4.2.6.p5+dfsg-3ubuntu2.14.04.10 | USN-3096-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | ntp +4 | 4.2.6p5-22.el7_2.2 | RHSA-2016:1141 |
| RHEL 6 | ntp +3 | 4.2.6p5-10.el6.1 | RHSA-2016:1141 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6.7 EUS | ntp +3 | 4.2.6p5-5.el6_7.5 | RHSA-2016:1552 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | ntp | 4.2.8p7-11.1 | SUSE-SU-2016:1291-1 |
| SLES 12 | ntp | 4.2.8p8-46.8.1 | SUSE-SU-2016:1568-1 |
| SLES 11 SP4 | ntp | 4.2.8p7-11.1 | SUSE-SU-2016:1278-1 |
| SLES 11 SP3 | ntp | 4.2.8p7-44.1 | SUSE-SU-2016:1471-1 |
| SLES 11 SP2 | ntp | 4.2.8p7-44.1 | SUSE-SU-2016:1471-1 |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | ntp | 4.2.8p7-11.1 | SUSE-SU-2016:1291-1 |
| SLES for SAP 12 | ntp | 4.2.8p8-46.8.1 | SUSE-SU-2016:1568-1 |
| SLES for SAP 11 SP4 | ntp | 4.2.8p7-11.1 | SUSE-SU-2016:1278-1 |
| SUSE OpenStack Cloud 5 | ntp | 4.2.8p7-44.1 | SUSE-SU-2016:1471-1 |
| SUSE Manager Proxy 2.1 | ntp | 4.2.8p7-44.1 | SUSE-SU-2016:1471-1 |
| SUSE Manager 2.1 | ntp | 4.2.8p7-44.1 | SUSE-SU-2016:1471-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | ntp | 4.2.8p9-1.1 | openSUSE-SU-2024:10181-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | ntp +4 | 4.2.6p5-22.el7_2.2 | ELSA-2016-1141 |
Advisories 16
- RHSA-2016:1141 Red Hat Security Advisory: ntp security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2016:1552 Red Hat Security Advisory: ntp security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DLA-559-1 ntp - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3629-1 ntp - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-3096-1 ntp vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- openSUSE-SU-2024:10181-1 ntp-4.2.8p9-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1471-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1568-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1291-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1278-1 Security update for ntp SUSE / openSUSE Security Updates · Feb 4, 2026
- ICSA-21-103-11 Siemens TIM 4R-IE Devices CISA ICS & IT advisories · Jun 10, 2025
- SSA-497656 SSA-497656: Multiple NTP Vulnerabilities in TIM 4R-IE Devices Siemens ProductCERT · Jun 10, 2025
- ICSA-21-159-11 Siemens SIMATIC NET CP 443-1 OPC UA CISA ICS & IT advisories · May 6, 2025
- VDE-2022-032 AUMA: Multiple Vulnerabilities in Automation Runtime NTP Service CERT@VDE · Aug 9, 2022
- SSA-211752 SSA-211752: Multiple NTP-Client Related Vulnerabilities in SIMATIC CP 443-1 OPC UA Siemens ProductCERT · Feb 8, 2022
- ELSA-2016-1141 Moderate: ntp security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · May 31, 2016
References
- USN-3096-1 vendor-advisory
- DSA-3629 vendor-advisory
- http://www.talosintelligence.com/reports/TALOS-2016-0082/
- http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
- RHSA-2016:1141 vendor-advisory
- SUSE-SU-2016:1912 vendor-advisory
- 88264 vdb-entry
- VU#718152 third-party-advisory
- RHSA-2016:1552 vendor-advisory
- 1035705 vdb-entry
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- https://security.netapp.com/advisory/ntap-20171004-0002/
- 20160428 Multiple Vulnerabilities in Network Time Protocol Daemon Affecting Cisco Products: April 2016 vendor-advisory
- FreeBSD-SA-16:16 vendor-advisory
- SUSE-SU-2016:2094 vendor-advisory
- openSUSE-SU-2016:1423 vendor-advisory
- GLSA-201607-15 vendor-advisory
- openSUSE-SU-2016:1329 vendor-advisory
- http://packetstormsecurity.com/files/136864/Slackware-Security-Advisory-ntp-Updates.html
- SUSE-SU-2016:1471 vendor-advisory
- https://www.talosintelligence.com/vulnerability_reports/TALOS-2016-0082
- FEDORA-2016-5b2eb0bf9c vendor-advisory
- SUSE-SU-2016:1291 vendor-advisory
- DSA-3629 vendor-advisory
- 20160429 [slackware-security] ntp (SSA:2016-120-01) mailing-list
- SUSE-SU-2016:1568 vendor-advisory
- 20160429 [slackware-security] ntp (SSA:2016-120-01) mailing-list
- SUSE-SU-2016:1278 vendor-advisory
- FEDORA-2016-ed8c6c0426 vendor-advisory
- https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf
- https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11
- https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf
- https://us-cert.cisa.gov/ics/advisories/icsa-21-159-11
- https://www.arista.com/en/support/advisories-notices/security-advisories/1332-security-advisory-19