CVE-2017-6463
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 · uneditedNTP before 4.2.8p10 and 4.3.x before 4.3.94 allows remote authenticated users to cause a denial of service (daemon crash) via an invalid setting in a :config directive, related to the unpeer option.
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 · high confidenceNTP versions before 4.2.8p10 and 4.3.x before 4.3.94 contain a vulnerability in the :config directive parser where an invalid setting related to the unpeer option can be used by an authenticated remote user to crash the NTP daemon, causing denial of service.
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= 4.2.8= 4.3.0= 4.3.1= 4.3.2= 4.3.3= 4.3.4= 4.3.5= 4.3.6= 4.3.7= 4.3.8= 4.3.9= 4.3.10CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify if NTP daemon is runningRun 'ps aux | grep ntpd' or check system service status (systemctl status ntpd or service ntpd status) to see if the ntpd process is activeAffected if NTP daemon is running and version is 4.2.8.x before p10 or 4.3.x before 4.3.94
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Determine installed NTP versionRun 'ntpd --version' or 'ntpq --version' or check the package version with 'dpkg -l | grep ntp' (Debian) or 'rpm -q ntp' (RHEL)Affected if Version is earlier than 4.2.8p10 in the 4.2.8 line, or 4.3.x where x is less than 94 (i.e., 4.3.0 through 4.3.93)
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Verify if remote configuration is enabledCheck /etc/ntp.conf for 'enable mode7' or inspect if ntpd is listening on control ports; use 'netstat -anp | grep 123' or 'ss -anp | grep 123' to see listening portsAffected if The NTP control/query interface (mode 7) is enabled and accessible over the network, allowing :config directive processing
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Confirm if authentication is required for remote configurationReview /etc/ntp.conf for 'trustedkey' or 'requestkey' directives, and verify that ntpq/ntpdc connections require authentication using 'ntpq -c rv'Affected if Remote configuration via :config directive is allowed without proper authentication or with weak access controls, enabling authenticated remote users to exploit the unpeer flaw
Your environment is affected if NTP daemon is running with a version earlier than 4.2.8p10 or 4.3.94, and the remote configuration interface is accessible to authenticated users.
Generated from the published advisory. Verify against your own configuration.
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 dataUpgrade NTP to version 4.2.8p10, 4.3.94, or later. Additionally, restrict access to the NTP configuration interface (ntpd - control and query via ntpq/ntpdc) to trusted authenticated users only to prevent exploitation.
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-6463 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2017-6463 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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