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NtpApplication

CVE-2016-9312

HIGH · 7.5 CVSS v3.0 Published 2017-01-13
Fix available
A fix is available. Upgrade to after 4.2.8 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
ntpd in NTP before 4.2.8p9, when running on Windows, allows remote attackers to cause a denial of service via a large UDP packet.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

ntpd on Windows versions before 4.2.8p9 is vulnerable to a denial-of-service attack via specially crafted large UDP packets sent to the NTP service port, causing the service to crash or become unresponsive.

MitigationUpdate ntpd to version 4.2.8p9 or later on all affected Windows systems. If immediate patching is not possible, consider restricting network access to NTP ports (123/UDP) via firewall rules to limit attack surface.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
NtpApplication
Affected:<= 4.2.8

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify ntpd is running on Windows
    Check running services: Open Services console (services.msc) and look for 'NTP' or 'Network Time Protocol' service, or run 'sc query' in command prompt to list services containing 'ntp'
    Affected if ntpd service is found running on the system
  2. Identify installed ntpd version
    Run 'ntpdc -V' or 'ntpd --version' from command prompt, or check the executable properties of ntpd.exe in the installation directory
    Affected if version displayed is 4.2.8 or earlier (any version <= 4.2.8)
  3. Confirm Windows platform
    Run 'systeminfo' or check OS version via 'winver' - this vulnerability specifically affects Windows implementations
    Affected if the operating system is Windows and ntpd version is <= 4.2.8
  4. Verify NTP port is accessible
    Check if UDP port 123 is open and listening: run 'netstat -an | findstr :123' or use PowerShell 'Get-NetUDPEndpoint -LocalPort 123'
    Affected if ntpd is listening on UDP port 123 and version is <= 4.2.8

A system is affected if it is running ntpd version 4.2.8 or earlier on Windows and has the NTP service (UDP port 123) exposed.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 4.2.8
Interim mitigation

Update ntpd to version 4.2.8p9 or later on all affected Windows systems. If immediate patching is not possible, consider restricting network access to NTP ports (123/UDP) via firewall rules to limit attack surface.

Fix this in Ntp Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2016-9312 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data