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CVE-2016-1551

UnknownEPSS 2.23%

Last modified

CVE-2016-1551 is a vulnerability of currently unknown severity. 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. EPSS estimates a 2.23% chance of exploitation in the next 30 days.

Description

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.

Metrics

EPSS Probability
2.23%

80.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
NtpNtp4.2.8P3
NtpsecNtpseca5fb34b9cc89b92a8fef2f459004865c93bb7f92—

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2016-1551?
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.
How severe is CVE-2016-1551?
Severity scoring for CVE-2016-1551 is pending analysis. The EPSS model estimates a 2.23% probability of exploitation in the next 30 days.
How do I fix CVE-2016-1551?
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-2016-1551?

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

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Source: NVD / NIST