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NtpApplication

CVE-2015-8138

MEDIUM · 5.3 CVSS v3.0 Published 2017-01-30
Fix available
A fix is available. Upgrade to after 4.2.8 or later.
See remediation →
62/100
Remediation priority · Elevated
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
NTP before 4.2.8p6 and 4.3.x before 4.3.90 allows remote attackers to bypass the origin timestamp validation via a packet with an origin timestamp set to zero.

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 confidence

NTP versions before 4.2.8p6 and 4.3.x before 4.3.90 contain a vulnerability where remote attackers can bypass origin timestamp validation by sending packets with the origin timestamp set to zero. This allows attackers to potentially spoof NTP responses and manipulate system time, which can undermine time-based security mechanisms and authentication protocols.

MitigationUpdate NTP to version 4.2.8p6 or later (or 4.3.90+ for 4.3.x branches). Consider enabling NTP authentication (using symmetric keys or autokey) as an additional layer of protection against spoofing attacks.

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= 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= 4.3.10= 4.3.11

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
Low
Availability
None

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

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. Check installed NTP daemon version
    Run 'ntpd --version' or 'ntpq -c version' to determine the exact NTP version installed
    Affected if The version is 4.2.8 or lower, OR the version is exactly 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, 4.3.10, or 4.3.11
  2. Verify NTP service is running
    Run 'systemctl status ntpd' or 'ps aux | grep ntpd' to confirm the NTP daemon is actively running
    Affected if The ntpd process is running and serving time to clients or querying upstream servers
  3. Confirm NTP operating mode
    Check /etc/ntp.conf for server or peer directives, or run 'ntpq -c peers' to see active time sources
    Affected if The system is configured as an NTP client querying remote servers, making it susceptible to spoofed responses
  4. Check if NTP authentication is disabled
    Review /etc/ntp.conf for 'trustedkey', 'requestkey', or 'controlkey' directives; absence of these indicates symmetric key authentication is not configured
    Affected if NTP authentication is not configured and the system uses unauthenticated NTP queries

Your system is affected if it runs a vulnerable NTP version (4.2.8 or lower, or any of the listed 4.3.x versions) as an active NTP client or server without authentication enabled.

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 NTP to version 4.2.8p6 or later (or 4.3.90+ for 4.3.x branches). Consider enabling NTP authentication (using symmetric keys or autokey) as an additional layer of protection against spoofing attacks.

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-2015-8138 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