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CVE Record

CVE-2016-1551: ntpd in NTP 4.2.8p3 and NTPsec a5fb34b9cc89b92a8fef2f459004865c93bb7f92 relies on the underlying operating...

ntpd in NTP 4.2.8p3 and NTPsec a5fb34b9cc89b92a8fef2f459004865c93bb7f92 relies on the underlying operating system to protect it from requests that impersonate reference clocks. Because reference clocks are treated like other peers and stored in the same structure, any packet with a source ip address of a reference clock (127.127.1.1 for example) that reaches the receive() function will match that reference clock's peer record and will be treated as a trusted peer. Any system that lacks the typical martian packet filtering which would block these packets is in danger of having its time controlled by an attacker.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysis

Security readout for executives and security teams

This flaw can let an attacker influence a vulnerable NTP server’s time if spoofed reference-clock packets reach ntpd and the operating system does not filter them. Time control can undermine systems that depend on reliable clocks. The provided sources do not show active exploitation or a CVSS score. Likely exposure is limited to systems running affected NTP 4.2.8p3, 4.2.8p4, or listed NTPsec commits where spoofed reference-clock-source packets can reach ntpd because OS filtering is absent or ineffective. Treat as a targeted infrastructure integrity risk, not an internet-wide emergency from the available evidence. Prioritize time sources supporting authentication, logging, certificate validation, incident response, or regulated operations. Mitigation focus: Check vendor advisories for fixed NTP or NTPsec packages.; Enable OS filtering for martian or invalid source addresses.; Block reference-clock-source packets from untrusted interfaces..

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Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
NTP ProjectNTP4.2.8p3, 4.2.8p4Listed
NTPsec ProjectNTPSec3e160db8dc248a0bcb053b56a80167dc742d2b74, a5fb34b9cc89b92a8fef2f459004865c93bb7f92Listed
Weakness

CWE details

No CWE listed

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