Vulnerabilidad RCE en Microsoft MSHTML (CVE-2021-40444)

ANÁLISIS

Esta vulnerabilidad permite al atacante ejecutar código remoto mediante documentos de Microsoft Office especialmente creados. El atacante puede crear un control ActiveX dentro del documento que ejecute internet explorer y de esta forma comprometer a los usuarios con permisos de administración. [2]

Productos afectados:

• Windows 7 for x64-based Systems Service Pack 1
• Windows 7 for 32-bit Systems Service Pack 1
• Windows Server 2012 R2 (Server Core installation)
• Windows Server 2012 R2
• Windows Server 2012 (Server Core installation)
• Windows Server 2012
• Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
• Windows Server 2008 R2 for x64-based Systems Service Pack 1
• Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
• Windows Server 2008 for x64-based Systems Service Pack 2
• Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
• Windows Server 2008 for 32-bit Systems Service Pack 2
• Windows RT 8.1
• Windows 8.1 for x64-based systems
• Windows 8.1 for 32-bit systems
• Windows Server 2016 (Server Core installation)
• Windows Server 2016
• Windows 10 Version 1607 for x64-based Systems
• Windows 10 Version 1607 for 32-bit Systems
• Windows 10 for x64-based Systems
• Windows 10 for 32-bit Systems
• Windows Server, version 20H2 (Server Core Installation)
• Windows 10 Version 20H2 for ARM64-based Systems
• Windows 10 Version 20H2 for 32-bit Systems
• Windows 10 Version 20H2 for x64-based Systems
• Windows Server, version 2004 (Server Core installation)
• Windows 10 Version 2004 for x64-based Systems
• Windows 10 Version 2004 for ARM64-based Systems
• Windows 10 Version 2004 for 32-bit Systems
• Windows Server 2022 (Server Core installation)
• Windows Server 2022
• Windows 10 Version 21H1 for 32-bit Systems
• Windows 10 Version 21H1 for ARM64-based Systems
• Windows 10 Version 21H1 for x64-based Systems
• Windows 10 Version 1909 for ARM64-based Systems
• Windows 10 Version 1909 for x64-based Systems
• Windows 10 Version 1909 for 32-bit Systems
• Windows Server 2019 (Server Core installation)
• Windows Server 2019
• Windows 10 Version 1809 for ARM64-based Systems
• Windows 10 Version 1809 for x64-based Systems
• Windows 10 Version 1809 for 32-bit Systems

Esta vulnerabilidad tiene una puntuación CVSSv3 oficial de 8.8, por lo que se considera de prioridad alta. [1]
Se puede encontrar una prueba de concepto de la vulnerabilidad en la siguiente fuente. [3]

RECOMENDACIONES

Esta vulnerabilidad quedó resuelta en el parche de Microsoft KB5005573 [4]. Se recomienda actualizar los productos afectados a esta versión.

REFERENCIAS

[1] https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2021-40444
[2] https://www.kaspersky.es/blog/cve-2021-40444-vulnerability-mshtml/25950/
[3] https://dl.packetstormsecurity.net/2109-exploits/MS_Windows_CVE-2021-40444.pdf
[4] https://support.microsoft.com/en-us/topic/september-14-2021-kb5005573-os-build-14393-4651-48853795-3857-4485-a2bf-f15b39464b41