CVE-2015-2360: Microsoft Win32k Privilege Escalation Vulnerability

CVE-2015-2360 is a privilege-escalation vulnerability in Microsoft Win32k, specifically involving the Win32k.sys kernel-mode driver component of Windows. Local users can abuse it to gain elevated privileges or trigger a denial-of-service condition. It matters because successful exploitation can let an attacker who already has a foothold on a system move from limited rights to full administrative or SYSTEM-level control, undermining isolation between users and the kernel.

Public detail is limited to the CISA summary and the associated CWE; exact affected builds, patch identifiers, and exploitation mechanics must be confirmed against the vendor advisory.

How it works

The weakness is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). In kernel-mode graphics and windowing code such as Win32k.sys, buffer-handling flaws can allow a local process to corrupt or misuse kernel memory. An attacker with the ability to run code as a standard user can craft inputs or calls that reach the vulnerable driver path, potentially overwriting critical structures or causing the system to crash. The result is either elevation of privileges or a denial-of-service. No further exploit specifics are provided in the available facts; defenders should treat this as a classic local kernel memory-safety issue and rely on the vendor advisory for precise trigger conditions.

Am I affected? How to find it in your systems

Win32k.sys is a core component of the Windows graphical subsystem and is present on essentially all supported desktop and server editions that include the Win32 windowing stack. Inventory efforts should focus on Windows hosts—workstations, terminal servers, and any servers that load the desktop or GDI components.

• Enumerate installed Windows versions and hotfixes across the estate using existing asset-management, WSUS/SCCM/Intune, or vulnerability-scanning tools.
• Confirm whether the specific security update that addresses CVE-2015-2360 has been applied; the exact KB or build numbers are not listed in the supplied facts and must be verified against the Microsoft advisory.
• Look for systems that still allow untrusted local code execution (shared workstations, VDI, jump hosts, or machines where users can install software).
• Telemetry signs of exploitation are generic for local privilege-escalation attempts: unexpected process elevation, crashes or bug-checks referencing win32k.sys, or anomalous calls into kernel graphics APIs. Correlate with endpoint-detection alerts for local privilege escalation.

How to remediate

The primary remediation is to apply the security updates Microsoft released for this vulnerability, following the vendor’s instructions exactly as stated in the CISA required action. After patching:

• Verify installation via the update history or by confirming the presence of the superseding cumulative update.
• Reboot as required so the updated Win32k.sys is loaded.
• For the broader class of kernel memory-corruption issues, enforce least privilege, keep Windows fully patched, and disable unnecessary interactive logons on servers.
• Maintain current endpoint-protection signatures and enable kernel-mode code-integrity features where supported.

If you can't patch immediately

Until the vendor update can be deployed, reduce the attack surface with compensating controls:

• Segment and restrict local interactive access; limit who can log on to high-value hosts.
• Apply application-control or allow-listing policies so untrusted binaries cannot execute.
• Use endpoint-detection and response rules tuned for local privilege-escalation behaviors and win32k-related crashes.
• Consider temporary virtual-patching or host-based intrusion-prevention rules if the security vendor supplies signatures for this CVE class, confirming coverage against the advisory.
• Disable or restrict features that increase exposure to untrusted local code where operationally feasible.

These measures lower likelihood and impact but do not replace the official patch.

If your data may have been exposed

Actively exploited local privilege-escalation vulnerabilities are commonly used after an initial foothold to deepen access and move laterally, which can lead to data theft or ransomware deployment; the supplied facts do not document ransomware use for this specific CVE. If you suspect compromise, isolate affected hosts, preserve forensic evidence, and follow your incident-response process. As a quick additional check, you can run a free exposure scan of your email addresses against known breach data sets to see whether credentials or personal information have already appeared in public dumps.