SARA / Free Tools / CVE / CVE-2020-13817

CVE-2020-13817 — ntpd in ntp before 4

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must

CVSS
5.9 MEDIUM
EPSS
0.35% (top 43.00%)
CWE
—
Published
2020-06-04T12:31:55.000Z
Last modified
2025-05-05T17:07:58.872Z
CVSS vector
CVSS:3.0/AC:H/AV:N/A:H/C:N/I:N/PR:N/S:U/UI:N

01What is this vulnerability?

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

02Affected products

VendorProductVersions
na / n/an/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

09References

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