CVE-2021-1732
Published: 25 February 2021
Summary
CVE-2021-1732 is a high-severity Out-of-bounds Write (CWE-787) vulnerability in Microsoft Windows 10 1803. Its CVSS base score is 7.8 (High).
Operationally, ranked in the top 0.5% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and AC-6 (Least Privilege).
Deeper analysis
CVE-2021-1732 is an elevation of privilege vulnerability in the Win32k component of Windows, assigned a CVSS 3.1 base score of 7.8 and categorized under CWE-787 for out-of-bounds write issues. The flaw stems from an offset confusion condition in ConsoleControl handling within the kernel-mode driver.
Local attackers with low privileges can exploit the vulnerability without user interaction to obtain full control over the affected system, resulting in high impact to confidentiality, integrity, and availability. Public proof-of-concept code demonstrating the offset confusion technique for privilege escalation has been published on PacketStorm.
Microsoft's security advisory at portal.msrc.microsoft.com provides official guidance on the issue, while multiple exploit implementations confirm the flaw's practical exploitability on unpatched systems.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-7196
Vulnerability details
Windows Win32k Elevation of Privilege Vulnerability
- CWE(s)
- KEV Date Added
- 03 November 2021
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires timely installation of the vendor patch that eliminates the offset-confusion flaw in Win32k.
Limits the initial low-privilege context an attacker must start from, reducing the value of a successful Win32k EoP.
Mandates memory-protection techniques (DEP, ASLR, etc.) that raise the difficulty of exploiting the out-of-bounds write in kernel memory.