Overview
On November 10, 2020 local time, Microsoft fixed two vulnerabilities in the Windows Network File System (NFS) in its monthly security updates, which are CVE-2020-17051 and CVE-2020-17056.
CVE-2020-17051 is a remote code execution vulnerability on the nfssvr.sys driver. It is said that the vulnerability can be reproduced to cause an immediate BSOD (Blue Screen of Death) within the driver [3].
CVE-2020-17056 is a remote out-of-bounds read vulnerability on the nfssvr.sys driver, which can lead to an address space layout randomization (ASLR) bypass.
The combination of these two vulnerabilities dramatically increases the likelihood of a remote exploit when used on the Windows Server to bypass exploit mitigations.
Microsoft has provided patches for affected systems. Users are advised to install patch updates as soon as possible.
NFS is a distributed client / server file system. Via Windows NFS, users can access other files in non-Windows operating systems (Linux or UNIX) on the computers that running Windows, just like accessing local files.
Reference links:
[1]https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2020-17051
[2]https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2020-17056
[3]https://www.mcafee.com/blogs/other-blogs/mcafee-labs/cve-2020-17051-remote-kernel-heap-overflow-in-nfsv3-windows-server/
Affected Versions
CVE-2020-17051
- Windows 10 Version 20H2 for 32-bit Systems
- Windows 10 Version 20H2 for ARM64-based Systems
- Windows 10 Version 20H2 for x64-based Systems
- Windows Server, version 20H2 (Server Core Installation)
- Windows 10 Version 1809 for 32-bit Systems
- Windows 10 Version 1809 for x64-based Systems
- Windows 10 Version 1809 for ARM64-based Systems
- Windows Server 2019
- Windows Server 2019 (Server Core installation)
- Windows 10 Version 1909 for 32-bit Systems
- Windows 10 Version 1909 for x64-based Systems
- Windows 10 Version 1909 for ARM64-based Systems
- Windows Server, version 1909 (Server Core installation)
- Windows 10 Version 1903 for 32-bit Systems
- Windows 10 Version 1903 for x64-based Systems
- Windows 10 Version 1903 for ARM64-based Systems
- Windows Server, version 1903 (Server Core installation)
- Windows 10 Version 2004 for 32-bit Systems
- Windows 10 Version 2004 for ARM64-based Systems
- Windows 10 Version 2004 for x64-based Systems
- Windows Server, version 2004 (Server Core installation)
- Windows 10 Version 1607 for 32-bit Systems
- Windows 10 Version 1607 for x64-based Systems
- Windows Server 2016
- Windows Server 2016 (Server Core installation)
- Windows 7 for 32-bit Systems Service Pack 1
- Windows 7 for x64-based Systems Service Pack 1
- Windows 8.1 for 32-bit systems
- Windows 8.1 for x64-based systems
- Windows RT 8.1
- Windows Server 2008 for 32-bit Systems Service Pack 2
- Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
- Windows Server 2008 for x64-based Systems Service Pack 2
- Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
- Windows Server 2008 R2 for x64-based Systems Service Pack 1
- Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
- Windows Server 2012
- Windows Server 2012 (Server Core installation)
- Windows Server 2012 R2
- Windows Server 2012 R2 (Server Core installation)
CVE-2020-17056
- Windows 10 Version 1803 for 32-bit Systems
- Windows 10 Version 1803 for x64-based Systems
- Windows 10 Version 1803 for ARM64-based Systems
- Windows 10 Version 1809 for 32-bit Systems
- Windows 10 Version 1809 for x64-based Systems
- Windows 10 Version 1809 for ARM64-based Systems
- Windows Server 2019
- Windows Server 2019 (Server Core installation)
- Windows 10 Version 1909 for 32-bit Systems
- Windows 10 Version 1909 for x64-based Systems
- Windows 10 Version 1909 for ARM64-based Systems
- Windows Server, version 1909 (Server Core installation)
- Windows 10 Version 1903 for 32-bit Systems
- Windows 10 Version 1903 for x64-based Systems
- Windows 10 Version 1903 for ARM64-based Systems
- Windows Server, version 1903 (Server Core installation)
- Windows 10 Version 2004 for 32-bit Systems
- Windows 10 Version 2004 for ARM64-based Systems
- Windows 10 Version 2004 for x64-based Systems
- Windows Server, version 2004 (Server Core installation)
- Windows 10 for 32-bit Systems
- Windows 10 for x64-based Systems
- Windows 10 Version 1607 for 32-bit Systems
- Windows 10 Version 1607 for x64-based Systems
- Windows Server 2016
- Windows Server 2016 (Server Core installation)
- Windows 8.1 for 32-bit systems
- Windows 8.1 for x64-based systems
- Windows RT 8.1
- Windows Server 2012
- Windows Server 2012 (Server Core installation)
- Windows Server 2012 R2
- Windows Server 2012 R2 (Server Core installation)
- Windows 10 Version 20H2 for ARM64-based Systems
- Windows Server, version 20H2 (Server Core Installation)
- Windows 10 Version 20H2 for x64-based Systems
- Windows 10 Version 20H2 for 32-bit Systems
Solution
Microsoft has released security patches for vulnerable systems. Affected users are strongly advised to install patch updates without delay. For patch updates, please visit the following links:
Statement
This advisory is only used to describe a potential risk. NSFOCUS does not provide any commitment or promise on this advisory. NSFOCUS and the author will not bear any liability for any direct and/or indirect consequences and losses caused by transmitting and/or using this advisory. NSFOCUS reserves all the rights to modify and interpret this advisory. Please include this statement paragraph when reproducing or transferring this advisory. Do not modify this advisory, add/delete any information to/from it, or use this advisory for commercial purposes without permission from NSFOCUS.
About NSFOCUS
NSFOCUS, Inc., a global network and cyber security leader, protects enterprises and carriers from advanced cyber attacks. The company’s Intelligent Hybrid Security strategy utilizes both cloud and on-premises security platforms, built on a foundation of real-time global threat intelligence, to provide multi-layered, unified and dynamic protection against advanced cyber attacks.
NSFOCUS works with Fortune Global 500 companies, including four of the world’s five largest financial institutions, organizations in insurance, retail, healthcare, critical infrastructure industries as well as government agencies. NSFOCUS has technology and channel partners in more than 60 countries, is a member of both the Microsoft Active Protections Program (MAPP), and the Cloud Security Alliance (CSA). A wholly owned subsidiary of NSFOCUS Technologies Group Co., Ltd., the company has operations in the Americas, Europe, the Middle East and Asia Pacific.
