CriticalCVE-2018-8440

    Microsoft Windows Privilege Escalation Vulnerability (CVE-2018-8440)

    Published In CISA KEV since Sources: CVE.org

    What is affected, what to do

    An elevation of privilege vulnerability exists when Windows improperly handles calls to Advanced Local Procedure Call (ALPC), aka "Windows ALPC Elevation of Privilege Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, 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. CISA lists it as used in ransomware campaigns. 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 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 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 x64-based Systems..Version 1803 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

    18.5 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 97.2

    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
    239.64 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
    18.5 %
    Elevated — model estimates 10-50% 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
    97.2
    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
    CISA assessment (SSVC)
    Exploitation: active · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 7 February 2025

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This CVE sits on CISA KEV because it has been a staple of ransomware toolkits since 2018 (CISA explicitly flags it as used in ransomware campaigns) and ranks among the CVEs most frequently exploited in the wild. Adversaries pair it with initial phishing or RDP access to elevate to SYSTEM, disable EDR, dump LSASS credentials and move laterally. High-risk profiles are terminal servers, VDI / Citrix farms, developer workstations and any multi-user legacy system without ESU coverage. Because the attack vector is local (AV:L), weight your priority by the number of interactive users per host and the length of the patch gap since 2018 — any still-unpatched host should be treated as potentially compromised and triaged forensically.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy the Microsoft September 2018 Patch Tuesday updates (released 2018-09-11): KB4457128 (Windows 10 1803), KB4457142 (1709), KB4457138 (1703), KB4457131 (1607), KB4457144 (Server 2016), KB4457129 / KB4457144 for Windows 8.1 / Server 2012 R2, KB4457145 (Server 2012), KB4457139 (Windows 7 / Server 2008 R2 Monthly Rollup) and KB4457134 (Server 2008).
      • Enumerate legacy systems without a patch path (Windows 7 without ESU, Server 2008 without ESU, RT 8.1); flag them as end-of-life risk and isolate or migrate immediately.
      • Audit local administrator rights — the exploit targets standard users, so every interactive logon (RDP, terminal, jump host) on an unpatched system is a candidate privilege-escalation launchpad.
      • Switch EDR policies from "monitor" to "block" for known ALPC / Task Scheduler exploit signatures (SchRpcSetSecurity abuse); the original "SandboxEscaper" PoC and derivatives have been public since August 2018.
      • Report patch compliance via WSUS / Intune / SCCM to incident management; prioritise multi-user hosts (RDS, Citrix, VDI, developer workstations).

    2. Runbook step 2

      Mitigation layers

      • Enable application whitelisting (WDAC, AppLocker) for executables under user-writable paths (%TEMP%, %APPDATA%, C:\Users*); the exploit typically drops a DLL or EXE into such a location.
      • Harden the Task Scheduler: monitor ACLs on C:\Windows\Tasks and C:\Windows\System32\Tasks; treat unexpected changes to .job files or task XML definitions as high-severity events.
      • Network segmentation: place jump hosts and privileged workstations into dedicated VLANs, strip outbound internet access on multi-user hosts, and enable Credential Guard and LSA Protection to raise the cost of post-exploitation credential dumping.
      • Roll out LAPS for local admin passwords — after a successful LPE attackers often extract the local SAM hash; unique, rotating passwords break lateral movement.
      • Enable Microsoft Defender Attack Surface Reduction rules, in particular "Block credential stealing from LSASS" (GUID 9e6c4e1f-7d60-472f-ba1a-a39ef669e4b2) and "Block process creations originating from PSExec and WMI commands".
      • For unpatched EoL systems: apply virtual patching via host IPS, revoke interactive logon rights for non-admin accounts and enforce MFA on every access path.

    3. Runbook step 3

      Detection rules

      • Sysmon EID 11 (FileCreate) for writes into C:\Windows\Tasks*.job by non-SYSTEM processes; Sigma shape: selection: EventID: 11 TargetFilename|contains: '\\Windows\\Tasks\\' NOT Image|endswith: '\\svchost.exe'.
      • Sysmon EID 1 (ProcessCreate) parent-child chain where schtasks.exe or a user-launched process spawns a child with IntegrityLevel: System on an interactively logged-on host — a textbook LPE indicator.
      • Windows Security EID 4688 combined with 4672 (Special Privileges assigned) for user accounts that normally do not hold admin rights; KQL: SecurityEvent | where EventID == 4672 and AccountType == "User" and Account !in (KnownAdmins).
      • EDR telemetry on DLL loads from user-writable paths into SYSTEM-context processes (Task Scheduler service, services.exe); focus on unsigned or freshly compiled binaries.
      • Hunt for unexpected DACL modifications on files under C:\Windows\System32 — the original PoC manipulates permissions through SchRpcSetSecurity by design.

    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 Windows improperly handles calls to Advanced Local Procedure Call (ALPC), aka "Windows ALPC Elevation of Privilege Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, 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
    • 32-bit Systems
    • Version 1803 for 32-bit Systems
    • x64-based Systems
    • Version 1703 for 32-bit Systems
    • Version 1709 for 32-bit Systems
    • Version 1803 for x64-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
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    MicrosoftWindows 10 Servers
    • version 1803 (Server Core Installation)
    • version 1709 (Server Core Installation)
    • —
    • —
    MicrosoftWindows 7
    • 32-bit Systems Service Pack 1
    • x64-based Systems Service Pack 1
    • —
    • —
    MicrosoftWindows 8.1
    • x64-based systems
    • 32-bit systems
    • —
    • —
    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
    • —
    • —
    • —
    • —
    • —
    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)
    • —
    • —
    • —
    MicrosoftWindows Server 2012
    • (Server Core installation)
    • —
    MicrosoftWindows Server 2012 R2
    • (Server Core installation)
    • —
    MicrosoftWindows Server 2016
    • (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_7—
    Windowsmicrosoftwindows_8.1—
    Windowsmicrosoftwindows_rt_8.1—
    Windowsmicrosoftwindows_server_2008r2
    Windowsmicrosoftwindows_server_2008—
    Windowsmicrosoftwindows_server_2012r2
    Windowsmicrosoftwindows_server_2012—
    Windowsmicrosoftwindows_server_2016—

    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

    References & sources

    • portal.msrc.microsoft.comen-US/security-guidance/advisory/CVE-2018-8440x_refsource_CONFIRM, Patch, Vendor advisory
    • blog.0patch.com2018/09/comparing-our-micropatch-with.htmlx_refsource_MISC, Third-party advisory
    • blog.0patch.com2018/08/how-we-micropatched-publicly-dropped.htmlx_refsource_MISC, Exploit, Patch, Third-party advisory
    • securitytracker.com1041578Vulnerability database, x_refsource_SECTRACK, Third-party advisory, Vulnerability database
    • securityfocus.com105153Vulnerability database, x_refsource_BID, Third-party advisory, Vulnerability database
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8440government-resource, US government resource
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