Not ratedCVE-2011-0997

    ISC DHCP: security vulnerability (CVE-2011-0997)

    Published Sources: CVE.org

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    What is affected, what to do

    dhclient in ISC DHCP 3.0.x through 4.2.x before 4.2.1-P1, 3.1-ESV before 3.1-ESV-R1, and 4.1-ESV before 4.1-ESV-R2 allows remote attackers to execute arbitrary commands via shell metacharacters in a hostname obtained from a DHCP message, as demonstrated by a hostname that is provided to dhclient-script.

    An exploit is publicly available. The available sources name no fixed version. Check the vendor guidance in the references below.

    Affected
    • ISC DHCP eq 3.0..3.0
    • ISC DHCP eq 3.0.1..3.0.1
    • ISC DHCP eq 3.0.2..3.0.2
    • ISC DHCP eq 3.0.3..3.0.3
    • ISC DHCP eq 3.0.4..3.0.4
    • ISC DHCP eq 3.0.5..3.0.5
    • ISC DHCP eq 3.0.6..3.0.6
    • ISC DHCP eq 3.1-esv..3.1-esv
    • ISC DHCP eq 3.1.0..3.1.0
    • ISC DHCP eq 3.1.1..3.1.1
    • ISC DHCP eq 3.1.2..3.1.2
    • ISC DHCP eq 3.1.3..3.1.3
    • ISC DHCP eq 4.1-esv..4.1-esv
    • ISC DHCP eq 4.2.0..4.2.0
    • ISC DHCP eq 4.2.1..4.2.1
    • Debian Linux eq 5.0..5.0
    • Debian Linux eq 6.0..6.0
    • Debian Linux eq 7.0..7.0
    • Canonical Ubuntu Linux eq 6.06..6.06
    • Canonical Ubuntu Linux eq 8.04..8.04
    • Canonical Ubuntu Linux eq 9.10..9.10
    • Canonical Ubuntu Linux eq 10.04..10.04
    • Canonical Ubuntu Linux eq 10.10..10.10

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

    Metrics

    —

    Priority

    No value is available for this vulnerability.

    —

    CVSS v3

    No value is available for this vulnerability.

    84.6 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.70

    Show all metrics
    Severity
    Not rated
    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
    79.52 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
    PoC (publicly reported)
    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
    84.6 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    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
    99.70
    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

    dhclient in ISC DHCP 3.0.x through 4.2.x before 4.2.1-P1, 3.1-ESV before 3.1-ESV-R1, and 4.1-ESV before 4.1-ESV-R2 allows remote attackers to execute arbitrary commands via shell metacharacters in a hostname obtained from a DHCP message, as demonstrated by a hostname that is provided to dhclient-script.

    Source: NVD (NIST), cvelistv5

    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
    iscdhcp
    • 3.0
    • 3.1.2
    • 3.0.4
    • 3.1.3
    • 3.1-esv
    • 3.0.1
    • 3.0.3
    • 3.0.2
    • 4.2.1
    • 3.0.5
    • 4.1-esv
    • 4.2.0
    • 3.1.0
    • 3.1.1
    • 3.0.6
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebiandebian_linux5.0
    Linuxdebiandebian_linux6.0
    Linuxdebiandebian_linux7.0
    Linuxcanonicalubuntu_linux10.04
    Linuxcanonicalubuntu_linux10.10
    Linuxcanonicalubuntu_linux6.06
    Linuxcanonicalubuntu_linux8.04
    Linuxcanonicalubuntu_linux9.10

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    Exploit-DBEDB-ID 37623 (opens in a new tab)exploit-db.comPoC (publicly reported)reported, not verified—

    References & sources

    • securityfocus.com47176Vulnerability database, x_refsource_BID, Third-party advisory, Vulnerability database
    • vupen.comADV-2011-0886Vulnerability database, x_refsource_VUPEN, Permissions required
    • secunia.com44103Third-party advisory, x_refsource_SECUNIA, Third-party advisory
    • redhat.comRHSA-2011:0840Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • secunia.com44037Third-party advisory, x_refsource_SECUNIA, Third-party advisory
    • bugzilla.redhat.comshow_bug.cgi?id=689832x_refsource_CONFIRM, Issue tracking, Patch, Third-party advisory
    • vupen.comADV-2011-0926Vulnerability database, x_refsource_VUPEN, Permissions required
    • marc.infoHPSBMU02752Vendor advisory, x_refsource_HP, Mailing list, Third-party advisory
    • secunia.com44127Third-party advisory, x_refsource_SECUNIA, Third-party advisory
    • mandriva.comMDVSA-2011:073Vendor advisory, x_refsource_MANDRIVA, Third-party advisory
    • vupen.comADV-2011-0909Vulnerability database, x_refsource_VUPEN, Permissions required
    • oval.cisecurity.orgoval:org.mitre.oval:def:12812Vulnerability database, signature, x_refsource_OVAL, Third-party advisory
    • osvdb.org71493Vulnerability database, x_refsource_OSVDB, Broken link
    • secunia.com44090Third-party advisory, x_refsource_SECUNIA, Third-party advisory
    • secunia.com44048Third-party advisory, x_refsource_SECUNIA, Third-party advisory
    • lists.fedoraproject.orgFEDORA-2011-4934Vendor advisory, x_refsource_FEDORA, Mailing list, Third-party advisory
    • isc.orgsoftware/dhcp/advisories/cve-2011-0997x_refsource_CONFIRM, Patch, Vendor advisory
    • exchange.xforce.ibmcloud.comiscdhcp-dhclient-command-execution(66580)Vulnerability database, x_refsource_XF, Third-party advisory, Vulnerability database
    • vupen.comADV-2011-0879Vulnerability database, x_refsource_VUPEN, Permissions required
    • kb.cert.orgVU#107886Third-party advisory, x_refsource_CERT-VN, Third-party advisory, US government resource
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