CVE-2024-49086
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Windows systems running Routing and Remote Access Service (RRAS) without authentication. Attackers can exploit this heap-based buffer overflow to gain SYSTEM privileges on affected systems. Organizations using Windows servers with RRAS enabled are primarily affected.
💻 Affected Systems
- Windows Server
- Windows
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with SYSTEM privileges, enabling attackers to install malware, steal credentials, pivot to other systems, and maintain persistent access.
Likely Case
Initial foothold leading to ransomware deployment, data exfiltration, or lateral movement within the network.
If Mitigated
Limited impact due to network segmentation, proper access controls, and monitoring preventing successful exploitation.
🎯 Exploit Status
Exploitation requires sending specially crafted packets to RRAS service. No authentication required, but requires understanding of RRAS protocol.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: July 2024 security updates (KB5040442 for Windows 10/11, KB5040434 for Server 2019, KB5040431 for Server 2022)
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-49086
Restart Required: Yes
Instructions:
1. Apply July 2024 Windows security updates via Windows Update. 2. For enterprise: Deploy patches through WSUS or SCCM. 3. Restart affected systems after patch installation.
🔧 Temporary Workarounds
Disable RRAS Service
windowsStop and disable Routing and Remote Access Service if not required
sc stop RemoteAccess
sc config RemoteAccess start= disabled
Block RRAS Ports
windowsBlock network access to RRAS ports (TCP 1723, UDP 1701, UDP 500, UDP 4500)
netsh advfirewall firewall add rule name="Block RRAS" dir=in action=block protocol=TCP localport=1723
netsh advfirewall firewall add rule name="Block RRAS UDP" dir=in action=block protocol=UDP localport=1701,500,4500
🧯 If You Can't Patch
- Disable RRAS service on all affected systems immediately
- Implement strict network segmentation to isolate RRAS servers from internet and critical internal networks
🔍 How to Verify
Check if Vulnerable:
Check if RRAS service is running: Get-Service RemoteAccess | Select Status, StartTypeCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify patch installation: wmic qfe list | findstr KB5040442 (or appropriate KB for your OS)📡 Detection & Monitoring
Log Indicators:
- Event ID 4688 with RRAS process creation
- Unexpected RRAS service restarts
- Security logs showing SYSTEM privilege escalation
Network Indicators:
- Unusual traffic to RRAS ports (1723, 1701, 500, 4500)
- Malformed packets to RRAS service
SIEM Query:
source="windows" AND (event_id=4688 AND process_name="svchost.exe" AND command_line LIKE "%RemoteAccess%") OR (event_id=4624 AND logon_type=3 AND account_name="SYSTEM")