CriticalCVE-2020-1054

    Win32k Elevation of Privilege Vulnerability (CVE-2020-1054)

    Published Last modified In CISA KEV since Sources: CVE.org

    What is affected, what to do

    An elevation of privilege vulnerability exists in Windows when the Windows kernel-mode driver fails to properly handle objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode.

    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 10 Version 1507 gte 10.0.10240.0..*
    • Microsoft Windows 10 Version 1607 gte 10.0.14393.0..*
    • Microsoft Windows 10 Version 1709 gte 10.0.0..*
    • Microsoft Windows 10 Version 1709 for 32-bit Systems gte 10.0.0..*
    • Microsoft Windows 10 Version 1803 gte 10.0.0..*
    • Microsoft Windows 10 Version 1809 gte 10.0.17763.0..*
    • Microsoft Windows 10 Version 1809 gte 10.0.0..*
    • Microsoft Windows 10 Version 1903 for 32-bit Systems gte 10.0.0..*
    • Microsoft Windows 10 Version 1903 for ARM64-based Systems gte 10.0.0..*
    • Microsoft Windows 10 Version 1903 for x64-based Systems gte 10.0.0..*
    • Microsoft Windows 10 Version 1909 gte 10.0.0..*
    • Microsoft Windows 7 gte 6.1.0..*
    • Microsoft Windows 7 Service Pack 1 gte 6.1.0..*
    • Microsoft Windows 8.1 gte 6.3.0..*
    • Microsoft Windows Server 2008 R2 Service Pack 1 gte 6.1.7601.0..*
    • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) gte 6.1.7601.0..*
    • Microsoft Windows Server 2008 Service Pack 2 gte 6.0.6003.0..*
    • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) gte 6.0.6003.0..*
    • Microsoft Windows Server 2012 gte 6.2.9200.0..*
    • Microsoft Windows Server 2012 (Server Core installation) gte 6.2.9200.0..*
    • Microsoft Windows Server 2012 R2 gte 6.3.9600.0..*
    • Microsoft Windows Server 2012 R2 (Server Core installation) gte 6.3.9600.0..*
    • Microsoft Windows Server 2016 gte 10.0.14393.0..*
    • Microsoft Windows Server 2016 (Server Core installation) gte 10.0.14393.0..*
    • Microsoft Windows Server 2019 gte 10.0.17763.0..*
    • Microsoft Windows Server 2019 (Server Core installation) gte 10.0.17763.0..*
    • Microsoft Windows Server, version 1803 (Server Core Installation) gte 10.0.0..*
    • Microsoft Windows Server, version 1903 (Server Core installation) gte 10.0.0..*
    • Microsoft Windows Server, version 1909 (Server Core installation) gte 10.0.0..*

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

    Metrics

    7.0

    Priority

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

    Source: NVD, CVSS v3

    7.0

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org

    53.9 %

    EPSS score

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

    Source: FIRST EPSS, percentile 99.00

    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
    213.41 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
    7.0 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
    7.0
    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
    53.9 %
    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
    99.00
    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-787

    Response and mitigation

    Why act now?

    Prioritisation rationale

    CVE-2020-1054 is a local privilege escalation in the Win32k kernel driver. A public, reliable exploit (including a Metasploit module) makes it a staple post-initial-access step: after phishing or a compromised VPN/RDP login, attackers use it to jump from user to SYSTEM. It requires a local logon and is technically more complex to exploit. Exploitation likelihood is still rated very high, because ready-made exploit code removes most of that hurdle. CISA does not flag ransomware use. Score it high for organisations running legacy Windows 10 builds, multi-user hosts (RDS/VDI) or incomplete patch management. For fully patched, supported builds, the remaining action is verifying patch compliance.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy the Microsoft May 2020 (Patch Tuesday) security update to every affected Windows 10 build (1507, 1607, 1709, 1803, 1809, 1903). Look up the matching cumulative update per build in the Microsoft advisory for CVE-2020-1054. Confirm installation via WSUS/Intune/SCCM compliance reporting, not just approval status.
      • Inventory out-of-support Windows 10 builds (including 1507, 1709, 1803, 1903). They receive no newer kernel fixes. Flag them as high-risk assets and prioritise them for upgrade or isolation.
      • Patch hosts with many interactive non-admin logons first: RDS/terminal servers, Citrix VDI, jump hosts and kiosk machines. The "local user" precondition is trivially met there.
      • Treat any endpoint with suspected or confirmed exploitation as fully compromised. Isolate it via EDR and rotate the local admin password (LAPS). Assume cached domain credentials are exposed and rotate them.
      • Verify EDR/AV signatures are current. Public PoCs and a Metasploit module (cve_2020_1054_drawiconex_lpe) exist, and mainstream products detect them.

    2. Runbook step 2

      Mitigation layers

      • Application control: Use WDAC or AppLocker to block unsigned binaries from user-writable paths (%TEMP%, %APPDATA%, Downloads, C:\Users\Public). The exploit requires the attacker to run a crafted application.
      • IAM / least privilege: Restrict interactive logon rights (SeInteractiveLogonRight, RDP) to those who need them. Deny interactive logon for service accounts. Enforce admin tiering so Tier-0 credentials never land on workstations.
      • Endpoint hardening: Enable Credential Guard and LSA protection (RunAsPPL). This limits blast radius after a successful escalation, especially LSASS credential dumping.
      • Exploit protection: Where compatible, apply the "Disable Win32k system calls" Exploit Protection policy to exposed processes such as browsers and Office. Enable the ASR rules that block Office child processes and executables delivered by email.
      • Network segmentation: Move unpatchable legacy hosts into a dedicated VLAN. Allow inbound traffic only from management hosts. Block outbound SMB 445/TCP, RDP 3389/TCP and WinRM 5985-5986/TCP towards server segments to contain post-escalation lateral movement.

    3. Runbook step 3

      Detection rules

      • Sysmon EID 1 / Security 4688: Flag a process running as NT AUTHORITY\SYSTEM whose parent runs as a standard user at medium integrity. The typical pattern is cmd.exe or powershell.exe as a SYSTEM child of a binary in %TEMP%. KQL: DeviceProcessEvents | where AccountSid == "S-1-5-18" and InitiatingProcessAccountSid != "S-1-5-18" and InitiatingProcessIntegrityLevel in ("Medium","Low")
      • Token manipulation: Hunt EDR telemetry for token swaps, where a process suddenly holds a SYSTEM token without a service start or UAC event. Most EDRs surface this as "token stealing" or "kernel exploit".
      • Post-escalation persistence: Look for Security events 4720 (account created), 4732 (member added to local Administrators) and 7045/4697 (new service) shortly after a non-privileged logon (4624, LogonType 2/10). SPL: index=wineventlog EventCode IN (4720,4732,7045) | stats values(EventCode) by host, _time span=10m
      • File telemetry: Watch for Sysmon EID 11 writing unsigned EXE/DLL files into user profiles, followed within minutes by a SYSTEM-context process start. Correlate with Defender/EDR detections naming CVE-2020-1054.
      • Crash indicators: Failed kernel exploits often trigger a bugcheck. Clusters of System event 1001 (BugCheck) or event 41 (Kernel-Power) referencing win32k on a single host are an early warning of exploitation attempts.

    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 Windows when the Windows kernel-mode driver fails to properly handle objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system. The update addresses this vulnerability by correcting how the Windows kernel-mode driver handles objects in memory.

    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 1507
    • ≥ 10.0.10240.0
    • —
    MicrosoftWindows 10 Version 1607
    • ≥ 10.0.14393.0
    • —
    MicrosoftWindows 10 Version 1709
    • ≥ 10.0.0
    • —
    MicrosoftWindows 10 Version 1709 for 32-bit Systems
    • ≥ 10.0.0
    • —
    MicrosoftWindows 10 Version 1803
    • ≥ 10.0.0
    • —
    MicrosoftWindows 10 Version 1809
    • ≥ 10.0.0
    • ≥ 10.0.17763.0
    • —
    • —
    MicrosoftWindows 10 Version 1903 for 32-bit Systems
    • ≥ 10.0.0
    • —
    MicrosoftWindows 10 Version 1903 for ARM64-based Systems
    • ≥ 10.0.0
    • —
    MicrosoftWindows 10 Version 1903 for x64-based Systems
    • ≥ 10.0.0
    • —
    MicrosoftWindows 10 Version 1909
    • ≥ 10.0.0
    • —
    MicrosoftWindows 7
    • ≥ 6.1.0
    • —
    MicrosoftWindows 7 Service Pack 1
    • ≥ 6.1.0
    • —
    MicrosoftWindows 8.1
    • ≥ 6.3.0
    • —
    MicrosoftWindows Server 2008 R2 Service Pack 1
    • ≥ 6.1.7601.0
    • —
    MicrosoftWindows Server 2008 R2 Service Pack 1 (Server Core installation)
    • ≥ 6.1.7601.0
    • —
    MicrosoftWindows Server 2008 Service Pack 2
    • ≥ 6.0.6003.0
    • —
    MicrosoftWindows Server 2008 Service Pack 2 (Server Core installation)
    • ≥ 6.0.6003.0
    • —
    MicrosoftWindows Server 2012
    • ≥ 6.2.9200.0
    • —
    MicrosoftWindows Server 2012 (Server Core installation)
    • ≥ 6.2.9200.0
    • —
    MicrosoftWindows Server 2012 R2
    • ≥ 6.3.9600.0
    • —
    MicrosoftWindows Server 2012 R2 (Server Core installation)
    • ≥ 6.3.9600.0
    • —
    MicrosoftWindows Server 2016
    • ≥ 10.0.14393.0
    • —
    MicrosoftWindows Server 2016 (Server Core installation)
    • ≥ 10.0.14393.0
    • —
    MicrosoftWindows Server 2019
    • ≥ 10.0.17763.0
    • —
    MicrosoftWindows Server 2019 (Server Core installation)
    • ≥ 10.0.17763.0
    • —
    MicrosoftWindows Server, version 1803 (Server Core Installation)
    • ≥ 10.0.0
    • —
    MicrosoftWindows Server, version 1903 (Server Core installation)
    • ≥ 10.0.0
    • —
    MicrosoftWindows Server, version 1909 (Server Core installation)
    • ≥ 10.0.0
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Windowsmicrosoftwindows_10_1507—
    Windowsmicrosoftwindows_10_1607—
    Windowsmicrosoftwindows_10_1709—
    Windowsmicrosoftwindows_10_1803—
    Windowsmicrosoftwindows_10_1809—
    Windowsmicrosoftwindows_10_1903—
    Windowsmicrosoftwindows_10_1909—
    Windowsmicrosoftwindows_7—
    Windowsmicrosoftwindows_8.1—
    Windowsmicrosoftwindows_rt_8.1—
    Windowsmicrosoftwindows_server_1803—
    Windowsmicrosoftwindows_server_1903—
    Windowsmicrosoftwindows_server_1909—
    Windowsmicrosoftwindows_server_2008r2
    Windowsmicrosoftwindows_server_2008—
    Windowsmicrosoftwindows_server_2012r2
    Windowsmicrosoftwindows_server_2012—
    Windowsmicrosoftwindows_server_2016—
    Windowsmicrosoftwindows_server_2019—

    Weakness classes (CWE)

    • CWE-787Out-of-bounds Write

      Base

      The product writes data past the end, or before the beginning, of the intended buffer.

      Entry at MITRE CWE-787

    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
    Packet StormMicrosoft Windows DrawIconEx Local Privilege Escalation (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—

    References & sources

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. NVD analysis modifiedNVD

    2. Record modifiedMicrosoft

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1054
      Referenceremoved
      https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1054
      —
      Reference typeremoved
      https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1054 Types: Patch, Vendor Advisory
      —

      Source identifier: secure@microsoft.com

    3. Record modifiedCISA ADP

      CVSS V3.1: before AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, after —

      Show 4 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      CVSSremoved
      AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
      —
      Referenceadded
      —
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-1054
      Referenceremoved
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-1054
      —
      Reference typeremoved
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-1054 Types: US Government Resource
      —

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    4. Record modifiedCVE Program

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      http://packetstormsecurity.com/files/160515/Microsoft-Windows-DrawIconEx-Local-Privilege-Escalation.html
      Referenceadded
      —
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1054
      Referenceremoved
      http://packetstormsecurity.com/files/160515/Microsoft-Windows-DrawIconEx-Local-Privilege-Escalation.html
      —
      Referenceremoved
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1054
      —
      Reference typeremoved
      http://packetstormsecurity.com/files/160515/Microsoft-Windows-DrawIconEx-Local-Privilege-Escalation.html Types: Exploit, Third Party Advisory, VDB Entry
      —
      Reference typeremoved
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1054 Types: Patch, Vendor Advisory
      —

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    5. Record modifiedMicrosoft

      CVSS V3.1: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

      Description added or changed

      Show 8 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)changed
      Windows, Windows Server, Windows 10 Version 1909 for 32-bit Systems (+7)
      Windows 10 Version 1507, Windows 10 Version 1607, Windows 10 Version 1709 (+26)
      Descriptionchanged
      An elevation of privilege vulnerability exists in Windows when the Windows kernel-mode driver fails to properly handle objects in memory, aka 'Win32k Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-1143.
      An elevation of privilege vulnerability exists in Windows when the Windows kernel-mode driver fails to properly handle objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take control of an affected system. The update addresses this vulnerability by correcting how the Windows kernel-mode driver handles objects in memory.
      CVSSadded
      —
      AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
      Referenceadded
      —
      https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-1054
      Referenceremoved
      http://packetstormsecurity.com/files/160515/Microsoft-Windows-DrawIconEx-Local-Privilege-Escalation.html
      —
      Referenceremoved
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1054
      —
      Reference typeremoved
      http://packetstormsecurity.com/files/160515/Microsoft-Windows-DrawIconEx-Local-Privilege-Escalation.html Types: Exploit, Third Party Advisory, VDB Entry
      —
      Reference typeremoved
      https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1054 Types: Patch, Vendor Advisory
      —

      Source identifier: secure@microsoft.com

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