CVE-2023-24901
📋 TL;DR
This vulnerability in Windows NFS Portmapper allows attackers to disclose sensitive information from memory. It affects Windows systems running NFS services, potentially exposing internal network details or system information to unauthorized parties.
💻 Affected Systems
- Windows NFS Portmapper
📦 What is this software?
Windows 10 1507 by Microsoft
Windows 10 1607 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 20h2 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 11 21h2 by Microsoft
Windows 11 22h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Attackers could extract sensitive memory contents including credentials, internal network information, or system configuration details, leading to further attacks.
Likely Case
Information disclosure revealing internal network structure, system details, or partial memory contents that could aid in reconnaissance for follow-up attacks.
If Mitigated
Limited information exposure with minimal impact if proper network segmentation and access controls are implemented.
🎯 Exploit Status
Microsoft rates this as 'Exploitation More Likely' in their advisory. The vulnerability allows information disclosure without authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply May 2023 security updates or later
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-24901
Restart Required: Yes
Instructions:
1. Install May 2023 Windows security updates via Windows Update. 2. For enterprise environments, deploy through WSUS or Microsoft Endpoint Configuration Manager. 3. Restart affected systems after patch installation.
🔧 Temporary Workarounds
Disable NFS Services
windowsDisable NFS services if not required for business operations
sc config nfssvc start= disabled
sc stop nfssvc
Network Segmentation
windowsRestrict network access to NFS services using firewall rules
netsh advfirewall firewall add rule name="Block NFS" dir=in action=block protocol=TCP localport=2049
netsh advfirewall firewall add rule name="Block NFS UDP" dir=in action=block protocol=UDP localport=2049
🧯 If You Can't Patch
- Disable NFS services on all affected systems immediately
- Implement strict network segmentation and firewall rules to restrict access to NFS ports (TCP/UDP 2049)
🔍 How to Verify
Check if Vulnerable:
Check if NFS services are running: 'sc query nfssvc' and verify Windows version is before May 2023 updatesCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify Windows Update history contains May 2023 security updates and NFS services are either patched or disabled📡 Detection & Monitoring
Log Indicators:
- Unusual NFS portmapper requests
- Multiple failed NFS connection attempts
- Unexpected memory access patterns in system logs
Network Indicators:
- Unusual traffic to TCP/UDP port 2049
- Multiple NFS requests from single sources
- Information disclosure patterns in NFS traffic
SIEM Query:
source="windows" AND (event_id=5156 OR event_id=5157) AND dest_port=2049 AND src_ip NOT IN (allowed_nfs_clients)