CriticalCVE-2018-8611

    Microsoft Windows Kernel Privilege Escalation Vulnerability (CVE-2018-8611)

    Published In CISA KEV since Sources: CVE.org

    What is affected, what to do

    An elevation of privilege vulnerability exists when the Windows kernel fails to properly handle objects in memory, aka "Windows Kernel Elevation of Privilege Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, Windows Server 2019, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers.

    The vulnerability is being actively exploited; treat it as a priority. The available sources name no fixed version. Check the vendor guidance in the references below. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Microsoft Windows 7 eq 32-bit Systems Service Pack 1..32-bit Systems Service Pack 1
    • Microsoft Windows 7 eq x64-based Systems Service Pack 1..x64-based Systems Service Pack 1
    • Microsoft Windows Server 2012 R2 eq (Server Core installation)..(Server Core installation)
    • Microsoft Windows RT 8.1 eq Windows RT 8.1..Windows RT 8.1
    • Microsoft Windows Server 2008 eq 32-bit Systems Service Pack 2..32-bit Systems Service Pack 2
    • Microsoft Windows Server 2008 eq 32-bit Systems Service Pack 2 (Server Core installation)..32-bit Systems Service Pack 2 (Server Core installation)
    • Microsoft Windows Server 2008 eq Itanium-Based Systems Service Pack 2..Itanium-Based Systems Service Pack 2
    • Microsoft Windows Server 2008 eq x64-based Systems Service Pack 2..x64-based Systems Service Pack 2
    • Microsoft Windows Server 2008 eq x64-based Systems Service Pack 2 (Server Core installation)..x64-based Systems Service Pack 2 (Server Core installation)
    • Microsoft Windows Server 2019 eq (Server Core installation)..(Server Core installation)
    • Microsoft Windows Server 2012 eq (Server Core installation)..(Server Core installation)
    • Microsoft Windows 8.1 eq 32-bit systems..32-bit systems
    • Microsoft Windows 8.1 eq x64-based systems..x64-based systems
    • Microsoft Windows Server 2016 eq (Server Core installation)..(Server Core installation)
    • Microsoft Windows Server 2008 R2 eq Itanium-Based Systems Service Pack 1..Itanium-Based Systems Service Pack 1
    • Microsoft Windows Server 2008 R2 eq x64-based Systems Service Pack 1..x64-based Systems Service Pack 1
    • Microsoft Windows Server 2008 R2 eq x64-based Systems Service Pack 1 (Server Core installation)..x64-based Systems Service Pack 1 (Server Core installation)
    • Microsoft Windows 10 eq 32-bit Systems..32-bit Systems
    • Microsoft Windows 10 eq Version 1607 for 32-bit Systems..Version 1607 for 32-bit Systems
    • Microsoft Windows 10 eq Version 1607 for x64-based Systems..Version 1607 for x64-based Systems
    • Microsoft Windows 10 eq Version 1703 for 32-bit Systems..Version 1703 for 32-bit Systems
    • Microsoft Windows 10 eq Version 1703 for x64-based Systems..Version 1703 for x64-based Systems
    • Microsoft Windows 10 eq Version 1709 for 32-bit Systems..Version 1709 for 32-bit Systems
    • Microsoft Windows 10 eq Version 1709 for ARM64-based Systems..Version 1709 for ARM64-based Systems
    • Microsoft Windows 10 eq Version 1709 for x64-based Systems..Version 1709 for x64-based Systems
    • Microsoft Windows 10 eq Version 1803 for 32-bit Systems..Version 1803 for 32-bit Systems
    • Microsoft Windows 10 eq Version 1803 for ARM64-based Systems..Version 1803 for ARM64-based Systems
    • Microsoft Windows 10 eq Version 1803 for x64-based Systems..Version 1803 for x64-based Systems
    • Microsoft Windows 10 eq Version 1809 for 32-bit Systems..Version 1809 for 32-bit Systems
    • Microsoft Windows 10 eq Version 1809 for ARM64-based Systems..Version 1809 for ARM64-based Systems
    • Microsoft Windows 10 eq Version 1809 for x64-based Systems..Version 1809 for x64-based Systems
    • Microsoft Windows 10 eq x64-based Systems..x64-based Systems
    • Microsoft Windows 10 Servers eq version 1709 (Server Core Installation)..version 1709 (Server Core Installation)
    • Microsoft Windows 10 Servers eq version 1803 (Server Core Installation)..version 1803 (Server Core Installation)

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    Metrics

    7.8

    Priority

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

    Source: NVD, CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org

    4.2 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 90.9

    Show all metrics
    Severity
    Critical
    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
    205.10 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
    actively exploited
    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
    7.8 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
    7.8
    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
    4.2 %
    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
    90.9
    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
    Actively exploited
    Published
    In CISA KEV since

    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

    Response and mitigation

    Why act now?

    Prioritisation rationale

    CVE-2018-8611 is a local kernel privilege escalation. Any low-privileged foothold can reach full SYSTEM without user interaction, with high impact on confidentiality, integrity and availability. It was used as a zero-day in targeted intrusions, as the second stage behind browser or document exploits to escape sandboxes. CISA lists no known ransomware use, but exploitation likelihood remains noticeably above average. In well-maintained estates the residual risk is low because the fix has shipped since late 2018. It deserves high priority wherever unsupported Windows builds, multi-user servers or neglected OT and line-of-business hosts persist, which is common in KRITIS environments. Any unpatched instance also signals a patch-management gap that NIS2 expects you to close.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy Microsoft's December 2018 security update (Patch Tuesday, 11 Dec 2018) or any later cumulative update to all affected Windows clients and servers. KB numbers vary by build and edition, so look them up in the Microsoft Security Update Guide entry for CVE-2018-8611. Any current monthly rollup supersedes and includes the fix.
      • Run an inventory sweep via WSUS, SCCM/Intune or your VM scanner for hosts lacking updates from December 2018 or later, using Get-HotFix or an OS build comparison. Pay special attention to out-of-support builds: Windows 10 1607/1703/1709, Windows 7 and Server 2008/2008 R2.
      • Treat unsupported systems without ESU as high-risk assets. Move them into an isolated segment, restrict interactive logons and set a dated replacement or migration plan.
      • Patch multi-user systems first: terminal servers, RDS/Citrix hosts, jump hosts, VDI pools and build servers. Many low-privileged accounts can run local code on these hosts.
      • On any host with a known initial compromise (phishing payload, webshell, compromised account), assume escalation to SYSTEM has already happened. Rotate local admin and service account passwords, verify LAPS, and treat cached domain credentials as exposed.

    2. Runbook step 2

      Mitigation layers

      • Endpoint hardening / application control: Enforce WDAC or AppLocker so standard users cannot launch unknown binaries from %TEMP%, %APPDATA%, Downloads or C:\Users\Public. The bug sits in the Kernel Transaction Manager (KTM) and requires local code execution, so blocking that prerequisite blunts the exploit.
      • Browser and sandbox layer: Keep browsers and document viewers current. This flaw is documented as a sandbox escape, and exploit chains typically pair it with a browser or document RCE. Enable Defender ASR rules, notably "Block executable files from running unless they meet a prevalence, age, or trusted list criterion" and "Block Office applications from creating child processes".
      • IAM / least privilege: Restrict interactive and RDP logon on servers to the appropriate admin tier via the GPO settings "Allow log on locally" and "Allow log on through Remote Desktop Services". Service accounts must not have interactive logon rights.
      • Credential protection: Enable Credential Guard and LSA protection (RunAsPPL). This makes credential theft harder after a successful SYSTEM escalation and limits lateral movement.
      • Network segmentation: For legacy hosts that cannot be patched, enforce default-deny egress and allow only required destinations. This disrupts payload staging and C2.

    3. Runbook step 3

      Detection rules

      • Sysmon EID 1 / Security EID 4688: A process running as NT AUTHORITY\SYSTEM (IntegrityLevel System) whose parent runs as a standard user at Medium or Low integrity. Sigma shape: ParentIntegrityLevel in (Medium, Low) AND IntegrityLevel = System AND Image endswith (\cmd.exe, \powershell.exe, \rundll32.exe).
      • EDR process ancestry: SYSTEM-level cmd.exe or powershell.exe descending from winword.exe, excel.exe, chrome.exe, msedge.exe, firefox.exe, or an unsigned binary in a user profile path. KQL: DeviceProcessEvents | where AccountSid == "S-1-5-18" and InitiatingProcessAccountSid != "S-1-5-18" and InitiatingProcessIntegrityLevel in ("Medium","Low").
      • Token manipulation: Review EDR telemetry and Defender for Endpoint alerts for "token stealing" or "kernel exploit" behaviour. A non-service process whose token switches to SYSTEM mid-execution is a strong signal.
      • Kernel instability: Watch for clusters of bugchecks on a single host (System EID 1001, EID 41 Kernel-Power). Crashes involving tm.sys or ntoskrnl.exe may indicate failed attempts to win the KTM race condition.
      • Post-escalation follow-on: New services (Security EID 4697 / System EID 7045), handle access to lsass.exe (Sysmon EID 10 with GrantedAccess 0x1010/0x1410), and local account creation or admin group changes (EID 4720/4732) shortly after a suspicious user process.

    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
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    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
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    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

    An elevation of privilege vulnerability exists when the Windows kernel fails to properly handle objects in memory, aka "Windows Kernel Elevation of Privilege Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, Windows Server 2019, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers.

    Source: NVD (NIST), cvelistv5, CISA KEV Catalog

    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
    MicrosoftWindows 10
    • Version 1809 for x64-based Systems
    • 32-bit Systems
    • Version 1803 for 32-bit Systems
    • Version 1809 for ARM64-based Systems
    • x64-based Systems
    • Version 1703 for 32-bit Systems
    • Version 1803 for ARM64-based Systems
    • Version 1809 for 32-bit Systems
    • Version 1709 for 32-bit Systems
    • Version 1803 for x64-based Systems
    • Version 1709 for ARM64-based Systems
    • Version 1607 for 32-bit Systems
    • Version 1703 for x64-based Systems
    • Version 1709 for x64-based Systems
    • Version 1607 for x64-based Systems
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    MicrosoftWindows 10 Servers
    • version 1803 (Server Core Installation)
    • version 1709 (Server Core Installation)
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    • —
    MicrosoftWindows 7
    • 32-bit Systems Service Pack 1
    • x64-based Systems Service Pack 1
    • —
    • —
    MicrosoftWindows 8.1
    • x64-based systems
    • 32-bit systems
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    MicrosoftWindows RT 8.1
    • Windows RT 8.1
    • —
    MicrosoftWindows Server 2008
    • x64-based Systems Service Pack 2 (Server Core installation)
    • 32-bit Systems Service Pack 2 (Server Core installation)
    • 32-bit Systems Service Pack 2
    • x64-based Systems Service Pack 2
    • Itanium-Based Systems Service Pack 2
    • —
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    MicrosoftWindows Server 2008 R2
    • x64-based Systems Service Pack 1
    • Itanium-Based Systems Service Pack 1
    • x64-based Systems Service Pack 1 (Server Core installation)
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    MicrosoftWindows Server 2012
    • (Server Core installation)
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    MicrosoftWindows Server 2012 R2
    • (Server Core installation)
    • —
    MicrosoftWindows Server 2016
    • (Server Core installation)
    • —
    MicrosoftWindows Server 2019
    • (Server Core installation)
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Windowsmicrosoftwindows_10_1607—
    Windowsmicrosoftwindows_10_1703—
    Windowsmicrosoftwindows_10_1709—
    Windowsmicrosoftwindows_10_1803—
    Windowsmicrosoftwindows_10_1809—
    Windowsmicrosoftwindows_7—
    Windowsmicrosoftwindows_8.1—
    Windowsmicrosoftwindows_rt_8.1—
    Windowsmicrosoftwindows_server_2008r2
    Windowsmicrosoftwindows_server_2008—
    Windowsmicrosoftwindows_server_2012r2
    Windowsmicrosoftwindows_server_2012—
    Windowsmicrosoftwindows_server_2016—
    Windowsmicrosoftwindows_server_2019—

    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
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited
    PoC-in-GitHub (nomi-sec)cve-2018-8611 (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    • securityfocus.com106082Vulnerability database, x_refsource_BID, Third-party advisory, Vulnerability database
    • portal.msrc.microsoft.comen-US/security-guidance/advisory/CVE-2018-8611x_refsource_CONFIRM, Patch, Vendor advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8611government-resource, US government resource
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