Microsoft Win32k Privilege Escalation Vulnerability (CVE-2016-0167)
Published In CISA KEV since Sources: CVE.org
What is affected, what to do
The kernel-mode driver in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, and Windows 10 Gold and 1511 allows local users to gain privileges via a crafted application, aka "Win32k Elevation of Privilege Vulnerability," a different vulnerability than CVE-2016-0143 and CVE-2016-0165.
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 Server 2008
eq r2..r2 - Microsoft Windows Server 2012
eq r2..r2
- Microsoft Windows Server 2008
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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
5.7 %
EPSS score
Moderate — model estimates 1-10% exploitation likelihood.
Source: FIRST EPSS, percentile 93.0
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- 233.13 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- 5.7 %
- 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- 93.0
- 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 10 February 2025
Response and mitigation
Why act now?
Prioritisation rationale
This flaw cannot be reached over the network. It is a dependable second stage: once phishing or a dropper lands code as a normal user, the Win32k kernel bug lifts it to SYSTEM so the attacker can kill security tooling, harvest credentials and push ransomware across the estate. CISA explicitly flags known ransomware campaign use, and its exploitation likelihood sits well above the typical CVE. Fully patched Windows 10/11 and Server 2016+ fleets carry little residual risk. Organisations still running legacy Windows (OT HMIs, medical devices, POS terminals, line-of-business servers on 2008/2012) should treat it as high priority, because on those hosts a single phishing click becomes full host takeover.
Runbook step 1
Immediate response (0-24 h)
- Inventory affected hosts: Identify every machine running Windows Vista SP2, Server 2008 SP2 / 2008 R2 SP1, Windows 7 SP1, Windows 8.1, RT 8.1, Server 2012 / 2012 R2, or Windows 10 1507 (Gold) and 1511. Use SCCM/Intune,
Get-ADComputer -Filter * -Properties OperatingSystem, or a CMDB reconciliation. Expect most hits in OT, lab, point-of-sale and line-of-business server estates. - Deploy the vendor fix: The patch is available from the vendor (Microsoft's April 2016 Win32k security update). Look up the bulletin and per-OS KB numbers in the vendor advisory. Verify the actual
win32k.sysfile version on each host rather than relying on WSUS compliance dashboards alone. - Isolate unpatchable and EOL systems: Move hosts without vendor support (Vista, unupgraded Windows 10 1507/1511, 2008 without ESU) into a dedicated segment. Strip internet access, mail clients and Office macro capability from them.
- Hunt for prior compromise: On affected hosts, search the last 30 days for SYSTEM-level processes spawned from standard-user parents (see Detection rules). Isolate any hits and capture memory before rebooting.
- Rotate credentials: If successful elevation is suspected, reset local admin passwords (LAPS) and any domain credentials cached on the host. With SYSTEM, dumping LSASS is trivial.
- Inventory affected hosts: Identify every machine running Windows Vista SP2, Server 2008 SP2 / 2008 R2 SP1, Windows 7 SP1, Windows 8.1, RT 8.1, Server 2012 / 2012 R2, or Windows 10 1507 (Gold) and 1511. Use SCCM/Intune,
Runbook step 2
Mitigation layers
- Application control (endpoint): Run AppLocker or WDAC in enforce mode and block execution from user-writable paths (
%TEMP%,%APPDATA%,%LOCALAPPDATA%,Downloads). The exploit requires a locally launched crafted binary, so if it cannot run, there is no elevation. - Cut off initial access: Because the bug is local-only, it is almost always chained with phishing. Block internet-sourced Office macros via GPO, enable ASR rules (block Office child processes, block executable content from email), and filter
.exe,.scr,.js,.htaand ISO/ZIP containers at the mail gateway. - IAM / least privilege: Remove standing local admin rights from end users and deploy LAPS. Enforce a tiered admin model so that domain admins never log on to workstations, which limits what SYSTEM on one box is worth.
- Network segmentation: Deny SMB/RDP/WinRM (445/tcp, 3389/tcp, 5985-5986/tcp) from legacy segments to servers and peer clients. Allow-list east-west traffic only to the services those hosts genuinely need, so post-elevation lateral movement is slowed.
- Credential store hardening: Enable LSA protection (
RunAsPPL=1) and, on supported Windows 10 builds, Credential Guard. Disable WDigest (UseLogonCredential=0).
- Application control (endpoint): Run AppLocker or WDAC in enforce mode and block execution from user-writable paths (
Runbook step 3
Detection rules
- Integrity-level jump (EDR/MDE):
DeviceProcessEvents | where ProcessIntegrityLevel == "System" and InitiatingProcessIntegrityLevel in ("Medium","Low") and InitiatingProcessFileName !in~ ("services.exe","svchost.exe","msiexec.exe"). This query surfaces the token-stealing pattern typical of kernel EoP exploits. - Sysmon EID 1 / Security 4688: Look for
cmd.exe,powershell.exeorrundll32.exerunning asNT AUTHORITY\SYSTEMwhoseParentImagelives under a user profile (C:\Users\*\AppData\*,\Temp\). Sigma shape:selection: IntegrityLevel: System, ParentImage|contains: '\AppData\'. - Kernel crashes as failed attempts: System Event ID 1001 (BugCheck) or WER reports naming
win32k.sysas the faulting module, plus Kernel-Power Event 41 on clients. Treat these as significant when clustered, or when they occur shortly after a user opens an attachment. - Post-elevation tradecraft: LSASS access (Sysmon EID 10,
TargetImage: lsass.exe,GrantedAccess: 0x1010or0x1FFFFF), new services (Event 7045) or scheduled tasks (Event 4698) created by unsigned binaries from user directories. - Ransomware staging:
vssadmin delete shadows,wbadmin delete catalog, orbcdedit /set recoveryenabled no(Sysmon EID 1). On a legacy host, treat any of these as a top-severity alert.
- Integrity-level jump (EDR/MDE):
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
The kernel-mode driver in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, and Windows 10 Gold and 1511 allows local users to gain privileges via a crafted application, aka "Win32k Elevation of Privilege Vulnerability," a different vulnerability than CVE-2016-0143 and CVE-2016-0165.
Source: NVD (NIST), cvelistv5, CISA KEV Catalog, CVE.org (MITRE)
Vendors and products
Affected operating systems
| Windows | microsoft | windows_10_1507 | — |
| Windows | microsoft | windows_10_1511 | — |
| Windows | microsoft | windows_7 | — |
| Windows | microsoft | windows_8.1 | — |
| Windows | microsoft | windows_rt_8.1 | — |
| Windows | microsoft | windows_server_2008 | r2 |
| Windows | microsoft | windows_server_2008 | — |
| Windows | microsoft | windows_server_2012 | r2 |
| Windows | microsoft | windows_server_2012 | — |
| Windows | microsoft | windows_vista | — |
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.
| CISA KEV Catalog | CISA Known Exploited Vulnerability (opens in a new tab)cisa.gov | actively exploited |
References & sources
- securitytracker.com1035529Vulnerability database, x_refsource_SECTRACK, Broken link, Third-party advisory, Vulnerability database
- securitytracker.com1035532Vulnerability database, x_refsource_SECTRACK, Broken link, Third-party advisory, Vulnerability database
- docs.microsoft.comMS16-039Vendor advisory, x_refsource_MS, Patch, Vendor advisory
- cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2016-0167government-resource, US government resource
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<a href="https://intel.neosec.eu/en/cve/CVE-2016-0167"><img src="https://intel.neosec.eu/badge/cve/CVE-2016-0167.svg?lang=en" alt="CVE-2016-0167 – NEOSEC Intel" height="20"></a>