MediumCVE-2015-7977

    NTP: NULL Pointer Dereference (CVE-2015-7977)

    Published Sources: CVE.org

    What is affected, what to do

    ntpd in NTP before 4.2.8p6 and 4.3.x before 4.3.90 allows remote attackers to cause a denial of service (NULL pointer dereference) via a ntpdc reslist command.

    Update NTP to version 4.3.90.

    Affected
    • NTP lte *..4.2.8
    • NTP lt 4.3.0..4.3.90
    • NTP eq 4.2.8..4.2.8
    • Oracle Linux eq 6..6
    • FreeBSD eq 9.3..9.3
    • FreeBSD eq 10.1..10.1
    • FreeBSD eq 10.2..10.2
    • Fedora eq 22..22
    • Fedora eq 23..23
    • Debian Linux eq 8.0..8.0
    • Debian Linux eq 9.0..9.0
    • Canonical Ubuntu Linux eq 12.04..12.04
    • Canonical Ubuntu Linux eq 14.04..14.04
    • Canonical Ubuntu Linux eq 16.04..16.04
    Fixed in
    • NTP 4.3.90

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    5.9

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    5.9

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: CVE.org

    6.3 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 93.6

    Show all metrics
    Severity
    Medium
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    99.57 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    5.9 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    5.9
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    6.3 %
    Moderate — model estimates 1-10% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    93.6
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    ntpd in NTP before 4.2.8p6 and 4.3.x before 4.3.90 allows remote attackers to cause a denial of service (NULL pointer dereference) via a ntpdc reslist command.

    Source: cvelistv5, NVD (NIST)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    netappclustered_data_ontap
    • —
    • —
    netapponcommand_balance
    • —
    • —
    ntpntp
    • 4.2.8
    • ≤ 4.2.8
    • 4.3.0 – < 4.3.90
    • —
    • —
    • 4.3.90

    Vendors and products

    Affected operating systems

    Affected operating systems
    BSDfreebsdfreebsd10.1
    BSDfreebsdfreebsd10.2
    BSDfreebsdfreebsd9.3
    Linuxdebiandebian_linux8.0
    Linuxdebiandebian_linux9.0
    Linuxoraclelinux6
    Linuxcanonicalubuntu_linux12.04
    Linuxcanonicalubuntu_linux14.04
    Linuxcanonicalubuntu_linux16.04
    Otherfedoraprojectfedora22
    Otherfedoraprojectfedora23
    Othersiemenstim_4r-ie_dnp3_firmware—
    Othersiemenstim_4r-ie_firmware—

    References & sources

    • tools.cisco.com20160120 Multiple Vulnerabilities in Network Time Protocol Daemon Affecting Cisco Products - January 2016Vendor advisory, x_refsource_CISCO, Third-party advisory
    • ubuntu.comUSN-3096-1Vendor advisory, x_refsource_UBUNTU, Third-party advisory
    • lists.opensuse.orgSUSE-SU-2016:1177Vendor advisory, x_refsource_SUSE, Broken link
    • debian.orgDSA-3629Vendor advisory, x_refsource_DEBIAN, Third-party advisory
    • support.ntp.orgbin/view/Main/NtpBug2939x_refsource_CONFIRM, Vendor advisory
    • oracle.comtechnetwork/topics/security/linuxbulletinapr2016-2952096.htmlx_refsource_CONFIRM, Third-party advisory
    • lists.opensuse.orgSUSE-SU-2016:1912Vendor advisory, x_refsource_SUSE, Third-party advisory
    • securitytracker.com1034782Vulnerability database, x_refsource_SECTRACK, Third-party advisory, Vulnerability database
    • lists.opensuse.orgopenSUSE-SU-2016:1292Vendor advisory, x_refsource_SUSE, Broken link
    • kb.cert.orgVU#718152Third-party advisory, x_refsource_CERT-VN, Third-party advisory, US government resource
    • lists.opensuse.orgSUSE-SU-2016:1247Vendor advisory, x_refsource_SUSE, Broken link
    • lists.fedoraproject.orgFEDORA-2016-8bb1932088Vendor advisory, x_refsource_FEDORA, Third-party advisory
    • rhn.redhat.comRHSA-2016:2583Vendor advisory, x_refsource_REDHAT, Broken link
    • security.netapp.comadvisory/ntap-20171031-0001x_refsource_CONFIRM, Third-party advisory
    • securityfocus.com81815Vulnerability database, x_refsource_BID, Third-party advisory, Vulnerability database
    • lists.opensuse.orgSUSE-SU-2016:1311Vendor advisory, x_refsource_SUSE, Broken link
    • rhn.redhat.comRHSA-2016:0780Vendor advisory, x_refsource_REDHAT, Broken link
    • support.ntp.orgbin/view/Main/SecurityNoticex_refsource_CONFIRM, Vendor advisory
    • lists.fedoraproject.orgFEDORA-2016-34bc10a2c8Vendor advisory, x_refsource_FEDORA, Third-party advisory
    • lists.opensuse.orgSUSE-SU-2016:2094Vendor advisory, x_refsource_SUSE, Broken link
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