CVE-2023-23405
📋 TL;DR
CVE-2023-23405 is a Remote Procedure Call Runtime Remote Code Execution Vulnerability that allows an attacker to execute arbitrary code on affected systems by sending specially crafted RPC requests. This affects Windows systems with the RPC runtime component. Successful exploitation could lead to complete system compromise.
💻 Affected Systems
- Microsoft Windows
📦 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
Full system compromise with SYSTEM privileges, enabling data theft, ransomware deployment, lateral movement, and persistent backdoor installation.
Likely Case
Remote code execution leading to malware installation, credential harvesting, and initial foothold for further network exploitation.
If Mitigated
Limited impact due to network segmentation, host-based firewalls blocking RPC ports, and proper patch management.
🎯 Exploit Status
Microsoft rates this as 'Exploitation More Likely' in their advisory. The vulnerability requires network access to RPC endpoints.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: March 2023 security updates or later
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-23405
Restart Required: Yes
Instructions:
1. Apply March 2023 Windows security updates via Windows Update. 2. For enterprise environments, deploy updates through WSUS or SCCM. 3. Restart systems after patch installation.
🔧 Temporary Workarounds
Block RPC ports at network perimeter
windowsRestrict access to RPC ports (135, 445, 49152-65535) using firewalls
netsh advfirewall firewall add rule name="Block RPC" dir=in action=block protocol=TCP localport=135,445,49152-65535
Disable unnecessary RPC services
windowsDisable RPC services not required for business operations
sc config "Remote Procedure Call (RPC)" start= disabled
sc stop "Remote Procedure Call (RPC)"
🧯 If You Can't Patch
- Implement network segmentation to isolate vulnerable systems
- Deploy host-based firewalls to restrict RPC traffic to trusted sources only
🔍 How to Verify
Check if Vulnerable:
Check Windows version and patch level via systeminfo command. If March 2023 updates are not installed, system is vulnerable.Check Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify KB5023696 (or later March 2023 updates) is installed via 'wmic qfe list' or 'Get-Hotfix -Id KB5023696' in PowerShell.📡 Detection & Monitoring
Log Indicators:
- Windows Security Event ID 4688 (process creation) from RPCSS service
- Unexpected RPC service crashes in System logs
- Suspicious network connections to RPC ports
Network Indicators:
- Unusual RPC traffic patterns
- Multiple connection attempts to RPC ports from single source
- RPC protocol anomalies
SIEM Query:
source="windows" event_id=4688 AND process_name="*rpc*" AND parent_process_name="svchost.exe"