Skip to main content
Mallory
HighCISA KEVExploited in the wildPublic exploit

Windows Win32k Elevation of Privilege Vulnerability

IdentifiersCVE-2021-1732CWE-269

CVE-2021-1732 is a local elevation-of-privilege vulnerability in the Windows Win32k subsystem. The provided content identifies it as a Win32k EoP flaw and notes that it was exploited in the wild by multiple threat actors, including BITTER and MoustachedBouncer. In observed intrusions, attackers used the vulnerability after initial compromise to execute malware components or auxiliary payloads with elevated rights. The content also states that CVE-2022-21882 was reportedly a patch bypass for CVE-2021-1732, indicating the original issue affected Win32k privilege-boundary enforcement in a way that remained operationally significant after initial remediation.

Share:
For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an attacker who already has code execution on a Windows host to elevate privileges locally. Based on the supplied reporting, this enabled threat actors to run malware components with elevated rights, facilitating post-compromise actions such as privileged execution of droppers, plugins, or other tooling. As a Win32k local privilege-escalation issue, the practical impact is compromise of the local security boundary and transition from a lower-privileged context to a more privileged one on the affected system.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce opportunities for post-compromise local exploitation by minimizing initial access vectors, restricting execution of untrusted code, enforcing application control, limiting user rights, and monitoring for suspicious child processes and privilege-escalation behavior involving Win32k exploitation. Because the vulnerability is local, mitigations that prevent or constrain attacker code execution on the endpoint are the most relevant interim controls. The content also shows actors chaining this flaw after delivery via phishing or adversary-in-the-middle malware staging, so hardening those upstream paths is also relevant.

Remediation

Patch, then assume compromise.

Apply Microsoft's security update for CVE-2021-1732 on affected Windows systems. Because the content notes that CVE-2022-21882 was reportedly a patch bypass for CVE-2021-1732, remediation should also include ensuring subsequent related Win32k fixes are installed, not just the original February 2021 patch. Maintain current cumulative Windows updates across the fleet to avoid exposure to both the original flaw and known bypasses.
PUBLIC EXPLOITS

Exploits

5 valid exploits after Mallory filtered fakes, detection scripts, and README-only repos (3 hidden).

VALID 5 / 8 TOTALView more in app
CVE-2021-1732_expMaturityPoCVerified exploit

This repository contains a working local privilege escalation exploit for CVE-2021-1732, a vulnerability in the Windows Win32k component affecting Windows 10 versions 1809 and 1909 x64. The main exploit logic is implemented in 'CVE-2021-1732_Exploit.cpp', which is a C++ source file. The exploit abuses window and menu object manipulation to achieve arbitrary kernel memory read/write, ultimately replacing the process token to gain SYSTEM privileges. The repository includes Visual Studio project files for building the exploit, as well as documentation in both English and Chinese. The exploit must be run locally on a vulnerable system and, if successful, provides a SYSTEM shell. No network or remote attack vector is present; the exploit is strictly local. The code is operational and demonstrates a full privilege escalation chain, but does not include a customizable payload framework.

linuxdyDisclosed Apr 2, 2021cpplocal
CVE-2021-1732MaturityPoCVerified exploit

This repository contains a working proof-of-concept (PoC) exploit for CVE-2021-1732, a local privilege escalation vulnerability in Microsoft Windows 10 (x64), specifically in the win32k.sys kernel component. The main exploit logic resides in 'CVE-2021-1732/CVE-2021-1732.cpp', which orchestrates the attack by creating and manipulating a large number of window objects, exploiting the desktop heap, and leveraging internal Windows APIs and structures. The exploit uses custom hooking (via HookLib) and direct system calls to manipulate kernel memory, ultimately allowing the attacker to overwrite process tokens and spawn a process with SYSTEM privileges. Supporting files include utility code for querying system handles and project files for building the exploit with Visual Studio. No network endpoints are present; the attack vector is strictly local, requiring code execution on the target machine. The code is a functional PoC and demonstrates a deep understanding of Windows internals and kernel exploitation techniques.

Pai-PoDisclosed Apr 23, 2021c++clocal
CVE-2021-1732MaturityPoCVerified exploit

This repository contains a working local privilege escalation exploit for CVE-2021-1732, a Windows kernel vulnerability affecting multiple versions of Windows 10 and Windows Server. The main file, 'CVE-2021-1732_Exploit.cpp', is a C++ implementation that leverages window and menu object manipulation to achieve arbitrary kernel memory read/write, ultimately elevating the attacker's privileges to SYSTEM. The exploit is operational and requires local access to a vulnerable system. The README provides a comprehensive list of affected Windows versions and a demonstration image. No network endpoints are present; the attack vector is purely local. The code interacts with Windows system DLLs (notably user32.dll) and kernel structures, and is intended for advanced users familiar with Windows internals and exploit development.

4dpDisclosed Mar 9, 2023cpplocal
CVE-2021-1732MaturityPoCVerified exploit

This repository contains a working local privilege escalation exploit for CVE-2021-1732, a vulnerability in the Windows kernel (win32k.sys) affecting multiple versions of Windows 10 and Windows Server. The main file, 'CVE-2021-1732_Exploit.cpp', is a C++ implementation that leverages window and menu object manipulation to achieve arbitrary kernel memory read/write, ultimately allowing the attacker to escalate privileges to SYSTEM. The exploit is operational and requires local access to a vulnerable system. The README provides a list of affected Windows versions and a demonstration image. No network endpoints are present; the attack vector is purely local. The code interacts with system DLLs such as user32.dll and targets the win32k.sys kernel driver. The repository is structured simply, with one exploit source file and a README.

fenalikDisclosed Nov 1, 2022cpplocal
Windows-Privilege-Escalation-CVE-2021-1732MaturityPoCVerified exploit

This repository contains a working local privilege escalation exploit for CVE-2021-1732, a vulnerability in the Windows kernel (Win32k component) affecting Windows 10 (versions 1803-20H2) and Windows Server 2019/2004. The main exploit logic is implemented in 'CVE-2021-1732/CVE-2021-1732.cpp', which orchestrates the attack by creating and manipulating window objects, spraying window handles, and abusing internal kernel structures via user-mode callbacks and desktop heap offsets. The exploit leverages custom hooks (via HookLib) and direct system calls to manipulate kernel memory and escalate privileges to SYSTEM. Supporting files include utility code for handle enumeration and project files for building the exploit. The README provides affected versions and a demonstration GIF. No network endpoints are present; the attack vector is strictly local, requiring code execution on a vulnerable Windows system. The exploit is operational and provides a SYSTEM shell or process upon success.

exploitblizzardDisclosed Apr 25, 2021c++xmllocal
EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Microsoft CorporationWindows 10 1803operating_system
Microsoft CorporationWindows 10 1809operating_system
Microsoft CorporationWindows 10 1909operating_system
Microsoft CorporationWindows 10 2004operating_system
Microsoft CorporationWindows 10 20h2operating_system
Microsoft CorporationWindows Server 1909operating_system
Microsoft CorporationWindows Server 2004operating_system
Microsoft CorporationWindows Server 2019operating_system
Microsoft CorporationWindows Server 20h2operating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence7

Every observed campaign linking this CVE to a named adversary.

Associated malware2

Malware families riding this exploit, with evidence and IOCs.

Detection signatures2

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.