CriticalCVE-2019-1215

    Microsoft Windows Privilege Escalation Vulnerability (CVE-2019-1215)

    Published In CISA KEV since Sources: CVE.org

    What is affected, what to do

    An elevation of privilege vulnerability exists in the way that ws2ifsl.sys (Winsock) handles objects in memory, aka 'Windows Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2019-1253, CVE-2019-1278, CVE-2019-1303.

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

    19.3 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 97.3

    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
    239.79 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
    19.3 %
    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
    97.3
    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
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-269

    Response and mitigation

    Why act now?

    Prioritisation rationale

    CVE-2019-1215 is a local privilege escalation in the Winsock helper driver ws2ifsl.sys. Any low-privileged foothold becomes full SYSTEM control with no user interaction, with high impact on confidentiality, integrity and availability. CISA flags it for known ransomware campaign use. Operators chain it after phishing or loader-based initial access to disable EDR, harvest credentials and stage encryption. Exploitation likelihood is very high and exploit details are public. Despite the local attack vector, treat it as high priority wherever legacy Windows 10 builds remain, especially on OT-adjacent workstations, terminal servers and kiosks. Fully patched, current builds are out of scope.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Build an inventory of every Windows 10 host on builds 1507, 1607, 1703 and 1709. Use Defender TVM (DeviceTvmSoftwareVulnerabilities | where CveId == "CVE-2019-1215") or SCCM/Intune reporting on OS build and installed cumulative update. Treat the Microsoft Security Update Guide entry for CVE-2019-1215 as authoritative, because additional builds and server SKUs may be affected.
      • Deploy the security update. A patch is available from the vendor; look up the KB number per build in the Microsoft Security Update Guide. Any current cumulative update for a supported build contains the fixed ws2ifsl.sys.
      • Escalate unsupported builds. Outside the LTSB/LTSC channels, 1507, 1607, 1703 and 1709 no longer receive updates. Upgrade these hosts to a supported build. Until then, treat them as high-risk assets and pull them out of production segments.
      • Patch multi-user and pivot systems first: RDS/terminal servers, Citrix VDAs, jump hosts and kiosks. On these hosts, unprivileged users can run code that this flaw turns into SYSTEM.
      • If you suspect compromise, isolate the host via EDR. Then rotate local admin passwords (LAPS) and reset every domain credential cached on that machine. With SYSTEM rights, dumping LSASS is trivial.

    2. Runbook step 2

      Mitigation layers

      • Application control: Use WDAC or AppLocker to block unsigned binaries from user-writable paths (%TEMP%, %APPDATA%, %USERPROFILE%\Downloads, C:\Users\Public). Local privilege escalation exploits usually land as standalone EXEs or are reflectively loaded.
      • Cut off initial access: The bug requires local code execution, so starve that stage. Enable these ASR rules: block Office child processes, block executable content from email/webmail, and block process creation from PSExec/WMI. Block internet-sourced macros via GPO.
      • IAM / least privilege: Remove local admin rights from standard users. Enforce the admin tier model so privileged domain accounts never log on to workstations. Enable Protected Users and Credential Guard to limit the blast radius once SYSTEM is obtained.
      • Network segmentation: Move unpatched or end-of-life hosts into a dedicated VLAN. Block SMB (445/tcp), RDP (3389/tcp) and WinRM (5985/5986/tcp) from that VLAN towards server and client networks to slow post-escalation lateral movement.
      • Endpoint hardening: Enable EDR tamper protection and run LSASS as PPL (RunAsPPL=1). This makes it harder for ransomware operators with SYSTEM rights to kill security tooling.

    3. Runbook step 3

      Detection rules

      • Sysmon EID 1 / Security 4688: Look for a process with User = NT AUTHORITY\SYSTEM or IntegrityLevel = System whose parent runs as a standard user. A typical example is cmd.exe/powershell.exe spawning a SYSTEM shell without services.exe or svchost.exe in between. Sigma shape: selection: IntegrityLevel: System + filter: ParentUser not in (SYSTEM, LOCAL SERVICE, NETWORK SERVICE).
      • Bugcheck telemetry: Failed use-after-free attempts often crash the box. Correlate bursts of System Event ID 41 (Kernel-Power) and Event ID 1001 (BugCheck) whose minidumps reference ws2ifsl.sys. KQL: Event | where EventID in (41,1001) | summarize count() by Computer | where count_ > 2.
      • Execution from user-writable paths: In Sysmon EID 1 or the EDR process tree, look for an unsigned EXE from \AppData\ or \Temp\ followed within seconds by SYSTEM-level children (whoami, net.exe, vssadmin, wmic shadowcopy).
      • Post-exploitation patterns: Sysmon EID 10 (ProcessAccess) against lsass.exe with GrantedAccess 0x1010 or 0x1410 from non-allowlisted processes. Security 7045/4697 (new service) shortly after a suspicious user logon. Event 1102 (security log cleared).
      • Ransomware staging: Watch for vssadmin delete shadows, bcdedit /set recoveryenabled no or wbadmin delete catalog executed by SYSTEM without a change ticket. Alert as critical and trigger automatic host isolation.

    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 in the way that ws2ifsl.sys (Winsock) handles objects in memory, aka 'Windows Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2019-1253, CVE-2019-1278, CVE-2019-1303.

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

    Affected operating systems

    Affected operating systems
    Windowsmicrosoftwindows_10_1507—
    Windowsmicrosoftwindows_10_1607—
    Windowsmicrosoftwindows_10_1703—
    Windowsmicrosoftwindows_10_1709—
    Windowsmicrosoftwindows_10_1803—
    Windowsmicrosoftwindows_10_1809—
    Windowsmicrosoftwindows_10_1903—
    Windowsmicrosoftwindows_7—
    Windowsmicrosoftwindows_8.1—
    Windowsmicrosoftwindows_rt_8.1—
    Windowsmicrosoftwindows_server_1803—
    Windowsmicrosoftwindows_server_1903—
    Windowsmicrosoftwindows_server_2008r2
    Windowsmicrosoftwindows_server_2008—
    Windowsmicrosoftwindows_server_2012r2
    Windowsmicrosoftwindows_server_2012—
    Windowsmicrosoftwindows_server_2016—
    Windowsmicrosoftwindows_server_2019—

    Weakness classes (CWE)

    • CWE-269Improper Privilege Management

      Class

      The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

      Entry at MITRE CWE-269

    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-2019-1215x_refsource_MISC, Patch, Vendor advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2019-1215government-resource, US government resource
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    <a href="https://intel.neosec.eu/en/cve/CVE-2019-1215"><img src="https://intel.neosec.eu/badge/cve/CVE-2019-1215.svg?lang=en" alt="CVE-2019-1215 – NEOSEC Intel" height="20"></a>