DETECTION OVERVIEW
Risk Factors
Attackers must have read or write permission to any file on an NFS share on the targeted system. However, authentication is not required if the NFS share is configured with anonymous write access. If the exploit is successful, the attacker can cause a denial of service (DoS) or gain control of the Windows Server.
Kill Chain
Risk Score
61
The NFS protocol enables file transfers between devices with Windows and non-Windows operating systems. Part of NFS is the Open Network Computing Remote Procedure Call (ONCRPC) protocol, which enables remote access and data transfer between devices. Transferred data is encoded data with the External Data Representation (XDR) format. When NFS version 3 is installed on Windows systems, the XDR driver (rpcxdr.sys) has a vulnerability in how it processes security parameters in NFS requests. The exploitation of this vulnerability can cause an out-of-bounds write in the XDR driver, which can lead to a denial of service (DoS) or remote code execution (RCE).
Install relevant patches for affected versions
Disable anonymous write access to NFS shares unless require