Published severityHigh→Operational priority:Critical, raised one band.upgradedsince 3 Mar 2022
Evidence used
CISA confirms exploitation in the wild.
A structured source references public exploit or proof-of-concept material.
Exploitation requires an existing local or physical foothold with privileges.
EPSS is 55.92% for the current model date.
Compensating controls
Validate the affected product branch and deploy the verified fixed release.
Restrict local access and enforce least privilege on affected hosts.
Increase monitoring for the attack path and post-exploitation behaviour described in the report.
Verification
Confirm that the asset runs Microsoft Win32k and falls inside the recorded affected range.
Verify the installed build against the product-specific fixed version after deployment.
Validate exposure, authentication requirements and compensating controls in the actual environment.
Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2015-1831
CISA KEV mirrored by ENISA
Win32k.sys in the kernel-mode drivers in Microsoft Windows Server 2003 SP2, Vista SP2, and Server 2008 SP2 allows local users to gain privileges via a crafted application, as exploited in the wild in April 2015, aka "Win32k Elevation of Privilege Vulnerability."
EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 3 Mar 2022. Evidence sources: cisa_kev.
ENISA score
7.8 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch now
CISA confirms exploitation in the wild and lists 2022-03-24 as the remediation due date.
Patch available
01
What, why and how
An unspecified vulnerability exists in the Win32k.sys kernel-mode driver in Microsoft Windows Server that allows a local attacker to execute arbitrary code with elevated privileges.
What
An unspecified vulnerability exists in the Win32k.sys kernel-mode driver in Microsoft Windows Server that allows a local attacker to execute arbitrary code with elevated privileges.
Why
The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.
How
An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may execute code or commands in the affected security context.
What
An unspecified vulnerability exists in the Win32k.sys kernel-mode driver in Microsoft Windows Server that allows a local attacker to execute arbitrary code with elevated privileges.
Why
The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.
How
An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may execute code or commands in the affected security context.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.Confirmed in the wild
CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2022-03-03. Known ransomware campaign use is recorded.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.Reference recorded
A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.
Likely attack path
local access → vulnerable operation → execute code or commands in the affected security context
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-264. Open the MITRE definition for the exact weakness description.
CVSS vector ?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
Only matched European and national findings are included. Language selectors and unavailable sources are omitted.
ENISA EUVD · EUVD-2015-1831Known-exploited evidence recorded
Win32k.sys in the kernel-mode drivers in Microsoft Windows Server 2003 SP2, Vista SP2, and Server 2008 SP2 allows local users to gain privileges via a crafted application, as exploited in the wild in April 2015, aka "Win32k Elevation of Privilege Vulnerability."
Official EUVD record ↗JVN iPedia · Japanese · JVNDB-2015-002417複数の Microsoft Windows 製品のカーネルモードドライバの Win32k.sys における権限昇格の脆弱性
複数の Microsoft Windows 製品のカーネルモードドライバの Win32k.sys には、権限を取得される脆弱性が存在します。 本脆弱性への攻撃が 2015 年 4 月に観測されています。 マイクロソフトセキュリティ情報には、この脆弱性は「Win32k の特権の昇格の脆弱性」と記載されています。
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Affected versionsThe structured affected or fixed version information changed.
Before
n/a: n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
After
n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Affected versionsThe structured affected or fixed version information changed.
Before
n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
After
n/a: n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.