CVE-2025-62549: Windows 10 1607 RRAS RCE Vulnerability

CVE-2025-62549 Overview

CVE-2025-62549 is an untrusted pointer dereference vulnerability in Microsoft Windows Routing and Remote Access Service (RRAS) that allows an unauthorized attacker to execute arbitrary code over a network. This vulnerability affects a wide range of Windows client and server operating systems, making it a significant concern for enterprise environments that rely on RRAS for VPN and routing functionality.

The vulnerability exists due to improper validation of pointer values within the RRAS service, enabling remote attackers to craft malicious network requests that trigger arbitrary code execution in the context of the affected service.

Critical Impact

Successful exploitation allows remote attackers to execute arbitrary code on vulnerable Windows systems running RRAS, potentially leading to complete system compromise without requiring authentication.

Affected Products

• Microsoft Windows 10 (versions 1607, 1809, 21H2, 22H2)
• Microsoft Windows 11 (versions 23H2, 24H2, 25H2)
• Microsoft Windows Server 2008 (SP2 and R2 SP1)
• Microsoft Windows Server 2012 and 2012 R2
• Microsoft Windows Server 2016, 2019, 2022, 2022 23H2, and 2025

Discovery Timeline

• December 9, 2025 - CVE-2025-62549 published to NVD
• December 24, 2025 - Last updated in NVD database

Technical Details for CVE-2025-62549

Vulnerability Analysis

This vulnerability is classified under CWE-822 (Untrusted Pointer Dereference), which occurs when a program dereferences a pointer that contains an attacker-controlled value. In the context of Windows RRAS, the service fails to properly validate pointer values received through network communications before using them in memory operations.

The RRAS service handles various routing and remote access protocols, processing incoming network packets that may contain structured data including memory addresses or offsets. When the service processes a maliciously crafted request containing an untrusted pointer value, it may dereference this attacker-controlled address, leading to arbitrary read or write operations in the service's memory space.

The attack can be executed remotely over a network and requires user interaction, though the specific interaction required depends on the attack scenario. Successful exploitation results in complete compromise of confidentiality, integrity, and availability of the affected system.

Root Cause

The root cause of CVE-2025-62549 lies in insufficient validation of pointer values within the RRAS service's packet processing logic. The vulnerability stems from the service trusting external input to contain valid memory addresses without performing adequate bounds checking or pointer validation before dereferencing.

This type of vulnerability typically occurs when:

• Input data structures containing pointer values are processed without sanitization
• Memory offsets provided in network packets are used directly without validation
• Serialized objects containing pointer references are deserialized without verification

Attack Vector

The attack vector for CVE-2025-62549 is network-based, allowing remote exploitation of vulnerable systems. An attacker can target Windows systems with RRAS enabled by sending specially crafted network packets to the service.

The exploitation flow involves the attacker constructing a malicious network request containing a crafted pointer value. When the RRAS service processes this request, it dereferences the untrusted pointer, allowing the attacker to redirect program execution or corrupt memory in a controlled manner. This can ultimately lead to arbitrary code execution with the privileges of the RRAS service.

Since RRAS typically runs with elevated privileges to perform routing and network management functions, successful exploitation may grant the attacker SYSTEM-level access to the compromised host.

Detection Methods for CVE-2025-62549

Indicators of Compromise

• Unexpected crashes or service restarts of the Routing and Remote Access Service (RemoteAccess service)
• Anomalous network traffic patterns targeting RRAS-related ports and protocols
• Unusual process spawning from svchost.exe hosting RRAS components
• Memory access violations or exception events logged for RRAS-related processes

Detection Strategies

• Deploy network intrusion detection signatures to identify malformed RRAS protocol packets
• Monitor Windows Event Logs for Application Error events (Event ID 1000) associated with RRAS service crashes
• Implement endpoint detection rules to identify suspicious memory access patterns in RRAS components
• Utilize vulnerability scanning tools to identify systems running RRAS with unpatched versions

Monitoring Recommendations

• Enable detailed logging for the Routing and Remote Access Service and review logs regularly
• Configure SIEM rules to alert on repeated RRAS service failures or restarts
• Monitor network traffic for connections to RRAS from unexpected source IP ranges
• Implement behavioral analysis to detect anomalous activity following RRAS service interactions

How to Mitigate CVE-2025-62549

Immediate Actions Required

• Apply the Microsoft security update referenced in the Microsoft Security Update Guide immediately
• If patching is not immediately possible, consider disabling the Routing and Remote Access Service on systems where it is not essential
• Restrict network access to RRAS services using firewall rules, limiting connections to trusted sources only
• Conduct an inventory of all systems running RRAS to prioritize patching efforts

Patch Information

Microsoft has released security updates to address CVE-2025-62549. Administrators should consult the Microsoft Security Update Guide for CVE-2025-62549 for detailed patch information and download links specific to their Windows versions.

Additional resources for detection and mitigation scripts are available from security researchers at Vicarius, including a detection script and mitigation script.

Workarounds

• Disable the Routing and Remote Access Service on systems where VPN or routing functionality is not required using services.msc or PowerShell
• Implement network segmentation to isolate systems running RRAS from untrusted network segments
• Configure host-based firewalls to restrict inbound connections to RRAS-related ports
• Deploy intrusion prevention systems with virtual patching capabilities to block known exploitation attempts

# Disable Routing and Remote Access Service (if not required)
# PowerShell command to stop and disable RRAS
Stop-Service -Name "RemoteAccess" -Force
Set-Service -Name "RemoteAccess" -StartupType Disabled

# Verify service status
Get-Service -Name "RemoteAccess" | Select-Object Name, Status, StartType