CVE-2025-53796
📋 TL;DR
A buffer over-read vulnerability in Windows Routing and Remote Access Service (RRAS) allows unauthorized attackers to read beyond allocated memory boundaries, potentially disclosing sensitive information from system memory. This affects Windows systems with RRAS enabled, particularly those configured for VPN or routing services.
💻 Affected Systems
- Windows Routing and Remote Access Service
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could read sensitive data from memory including credentials, encryption keys, or other process information, leading to privilege escalation or lateral movement.
Likely Case
Information disclosure of random memory contents, potentially revealing system state information or partial data that could aid further attacks.
If Mitigated
Limited information disclosure with no direct code execution, but still revealing system information that could inform targeted attacks.
🎯 Exploit Status
Requires network access to RRAS service and ability to send specially crafted packets. No authentication required once network access is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Latest Windows security updates for affected versions
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53796
Restart Required: Yes
Instructions:
1. Apply latest Windows security updates via Windows Update. 2. For enterprise environments, deploy updates through WSUS or Microsoft Endpoint Configuration Manager. 3. Restart affected systems to complete installation.
🔧 Temporary Workarounds
Disable RRAS Service
WindowsTemporarily disable Routing and Remote Access Service if not required
sc config RemoteAccess start= disabled
sc stop RemoteAccess
Block RRAS Ports
WindowsBlock network access to RRAS ports (typically 1723 for PPTP, 1701 for L2TP, 500/4500 for IKEv2)
netsh advfirewall firewall add rule name="Block RRAS" dir=in action=block protocol=TCP localport=1723,1701
netsh advfirewall firewall add rule name="Block RRAS UDP" dir=in action=block protocol=UDP localport=500,4500
🧯 If You Can't Patch
- Disable RRAS service if not required for business operations
- Implement network segmentation to isolate RRAS servers from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check if RRAS service is running: sc query RemoteAccess | findstr "RUNNING"Check Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify Windows Update history contains the latest security updates and RRAS service version matches patched version📡 Detection & Monitoring
Log Indicators:
- Windows Security logs showing unexpected RRAS service access
- Event ID 20159 in RRAS logs indicating malformed packets
Network Indicators:
- Unusual traffic patterns to RRAS ports
- Multiple connection attempts with malformed packets
SIEM Query:
source="Windows Security" AND (event_id=4625 OR event_id=4648) AND process_name="svchost.exe" AND service_name="RemoteAccess"