CVE-2022-24491 Overview
CVE-2022-24491 is a critical remote code execution vulnerability affecting the Windows Network File System (NFS) component across multiple Microsoft Windows operating systems. This vulnerability allows an unauthenticated attacker to execute arbitrary code on vulnerable systems by sending specially crafted NFS requests over the network. The Windows NFS service, when enabled, provides file sharing capabilities between Windows and Unix/Linux systems, making it a high-value target in enterprise environments.
Critical Impact
This vulnerability enables unauthenticated remote code execution with no user interaction required, potentially allowing complete system compromise of Windows servers and workstations running the NFS service.
Affected Products
- Microsoft Windows 10 (all versions including 1607, 1809, 1909, 20H2, 21H1, 21H2)
- Microsoft Windows 11 (x64 and ARM64)
- Microsoft Windows 8.1 and Windows RT 8.1
- Microsoft Windows Server 2012 and 2012 R2
- Microsoft Windows Server 2016 (including 20H2)
- Microsoft Windows Server 2019
- Microsoft Windows Server 2022
Discovery Timeline
- April 15, 2022 - CVE-2022-24491 published to NVD
- November 21, 2024 - Last updated in NVD database
Technical Details for CVE-2022-24491
Vulnerability Analysis
This remote code execution vulnerability exists in the Windows Network File System (nfssvr.sys) driver. The vulnerability can be exploited by an unauthenticated attacker sending malicious network packets to a Windows system with the NFS role enabled. The attack requires no privileges and no user interaction, allowing attackers to compromise systems remotely without any authentication.
The vulnerability is particularly dangerous for Windows Server deployments where NFS is commonly enabled to provide interoperability with Unix-based systems. When successfully exploited, an attacker gains code execution in the context of the NFS service, which typically runs with elevated system privileges.
Root Cause
The vulnerability stems from improper handling of NFS protocol requests within the Windows NFS server implementation. The NFS driver fails to properly validate certain input parameters in network requests, leading to a condition where an attacker can influence memory operations and achieve code execution.
Attack Vector
Exploitation occurs entirely over the network through the NFS protocol (typically TCP port 2049). An attacker can target any system with the NFS Server role or feature enabled by:
- Identifying systems with the NFS service exposed on the network
- Sending specially crafted NFS requests designed to trigger the vulnerability
- Achieving arbitrary code execution without any authentication or user interaction
The attack does not require credentials or any form of user interaction, making it highly suitable for automated exploitation and worm-like propagation across networks where NFS is deployed.
Detection Methods for CVE-2022-24491
Indicators of Compromise
- Unexpected crashes or restarts of the NFS Server service (nfssvc.exe)
- Unusual network traffic patterns on TCP port 2049 (NFS)
- Anomalous process creation events originating from NFS service processes
- Memory corruption artifacts in Windows crash dumps related to nfssvr.sys
Detection Strategies
- Monitor for abnormal NFS protocol traffic and malformed NFS requests targeting Windows servers
- Implement network intrusion detection signatures for known CVE-2022-24491 exploit patterns
- Enable Windows Event logging for NFS service events and monitor for service failures
- Deploy endpoint detection and response (EDR) solutions to detect exploitation attempts and post-exploitation activity
Monitoring Recommendations
- Configure network monitoring to alert on unexpected NFS traffic to non-NFS server systems
- Implement log aggregation for NFS service events across all Windows servers
- Monitor for unusual child processes spawned by NFS-related services
- Set up alerts for multiple NFS service restarts within a short time period
How to Mitigate CVE-2022-24491
Immediate Actions Required
- Apply the Microsoft security update released in the April 2022 Patch Tuesday immediately
- If patching is not immediately possible, disable the NFS Server role on systems where it is not required
- Restrict network access to NFS services using firewall rules to limit exposure
- Segment networks to isolate systems running NFS services from untrusted network zones
Patch Information
Microsoft addressed this vulnerability in the April 2022 security updates. Organizations should apply the appropriate cumulative update for their Windows version as soon as possible. Detailed patch information and download links are available through the Microsoft Security Update Guide.
Workarounds
- Disable the NFS Server feature on systems that do not require it using PowerShell: Disable-WindowsOptionalFeature -FeatureName ServicesForNFS-ServerAndClient -Online
- Block TCP port 2049 at the firewall for systems that do not need external NFS access
- Use network segmentation to restrict which systems can communicate with NFS servers
- Implement strict access control lists (ACLs) on firewalls to limit NFS traffic to known, trusted IP addresses only
# Disable NFS Server feature on Windows Server
Disable-WindowsOptionalFeature -FeatureName ServicesForNFS-ServerAndClient -Online
# Block NFS port using Windows Firewall
New-NetFirewallRule -DisplayName "Block NFS" -Direction Inbound -Protocol TCP -LocalPort 2049 -Action Block
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
