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NtpApplication

CVE-2015-8158

MEDIUM · 5.9 CVSS v3.0 Published 2017-01-30
Fix available
A fix is available. Upgrade to after 4.2.8 or later.
See remediation →
68/100
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
The getresponse function in ntpq in NTP versions before 4.2.8p9 and 4.3.x before 4.3.90 allows remote attackers to cause a denial of service (infinite loop) via crafted packets with incorrect values.

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

The getresponse function in ntpq (NTP query tool) contains a denial of service vulnerability where crafted packets with incorrect values trigger an infinite loop. This affects NTP versions before 4.2.8p9 and 4.3.x before 4.3.90, allowing remote attackers to hang the ntpq process by sending malicious responses.

MitigationUpgrade NTP to version 4.2.8p9 or later (or 4.3.90+ for 4.3.x branches) to patch the vulnerable getresponse function. Additionally, restrict network access to NTP services to limit exposure to untrusted remote attackers.

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:H/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 NTP version is installed
    Run 'ntpq --version' or 'ntpd --version' to check the installed NTP version number
    Affected if The version shown is 4.2.8 or lower, or 4.3.0 through 4.3.11 (excluding 4.3.90 and higher)
  2. Confirm ntpq binary presence
    Run 'which ntpq' to locate the ntpq binary, typically found in /usr/bin/ntpq or /usr/sbin/ntpq
    Affected if The ntpq binary exists on the system and the NTP version is in the affected range
  3. Check if NTP services are network-accessible
    Run 'netstat -anp | grep -E "(123|ntp)"' or 'ss -anp | grep -E "(123|ntp)"' to see if NTP ports are listening on network interfaces
    Affected if Port 123/UDP is listening on a non-localhost address, exposing the service to remote attackers
  4. Identify active NTP client or server processes
    Run 'ps aux | grep -E "ntp|ntpd|ntpq"' to find running NTP-related processes
    Affected if ntpd or ntpq processes are running and the version is in the affected range
  5. Review NTP configuration for remote access
    Inspect /etc/ntp.conf or /etc/ntp/ntp.conf for 'restrict' directives that allow unrestricted remote queries
    Affected if The configuration permits queries from untrusted remote hosts without proper restrictions

A system is affected if it runs NTP version 4.2.8 or lower, or version 4.3.0-4.3.11, has ntpq installed, and exposes NTP services to untrusted network paths.

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

Upgrade NTP to version 4.2.8p9 or later (or 4.3.90+ for 4.3.x branches) to patch the vulnerable getresponse function. Additionally, restrict network access to NTP services to limit exposure to untrusted remote attackers.

Fix this in Ntp Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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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-2015-8158 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