CVE-2009-3563

unknown

Published — · Modified —

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CVSS v3

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CVSS v4 NEW

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not yet in upstream

VIR risk

1.0

Description

ntp_request.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial of service (CPU and bandwidth consumption) by using MODE_PRIVATE to send a spoofed (1) request or (2) response packet that triggers a continuous exchange of MODE_PRIVATE error responses between two NTP daemons.

Predictions

Exploit likelihood

20%

Patch ETA

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Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

Exploits

Public proof-of-concept code below. AS-IS, for defenders and authorised testing only.

Metasploit modules

auxiliary_dos/ntp/ntpd_reserved_dos rank 300

NTP.org ntpd Reserved Mode Denial of Service

Source fetch failed: fetch_error — view the original via the link above.

OS impact

Debian Fixed 1 release

Version	Status	Fixed in
bullseye	Fixed	`1:4.2.4p8+dfsg-1`

References

https://security-tracker.debian.org/tracker/CVE-2009-3563

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.