CVE-2025-62452: Windows 10 1607 Buffer Overflow Flaw

CVE-2025-62452 Overview

CVE-2025-62452 is a heap-based buffer overflow vulnerability in the Windows Routing and Remote Access Service (RRAS). An authorized attacker can exploit this flaw to execute arbitrary code over a network. The vulnerability affects a wide range of Microsoft Windows client and server operating systems, from Windows Server 2008 through Windows Server 2025 and Windows 10 through Windows 11 25H2. The weakness is categorized under CWE-122, heap-based buffer overflow. Successful exploitation requires low-level privileges and user interaction, but yields high impact on confidentiality, integrity, and availability of the affected system.

Critical Impact

Successful exploitation enables remote code execution within the RRAS service context, allowing attackers to compromise affected Windows hosts and pivot through enterprise routing infrastructure.

Affected Products

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

Discovery Timeline

• 2025-11-11 - CVE-2025-62452 published to NVD
• 2025-11-14 - Last updated in NVD database

Technical Details for CVE-2025-62452

Vulnerability Analysis

The vulnerability resides in the Windows Routing and Remote Access Service (RRAS), a Microsoft component that provides routing, virtual private network (VPN), and dial-up connectivity for Windows Server deployments. RRAS processes network protocol data structures across multiple routing scenarios. A heap-based buffer overflow (CWE-122) occurs when the service writes more data into a heap-allocated buffer than it was provisioned to hold. Attackers who supply crafted input to RRAS can corrupt adjacent heap structures and ultimately redirect execution flow within the service process.

Root Cause

The root cause is improper validation of the size or structure of data accepted by RRAS prior to copying it into a fixed-size heap buffer. When the parsing routine handles attacker-controlled fields without enforcing strict length checks, the resulting out-of-bounds write corrupts heap metadata or function pointers. This category of memory corruption commonly leads to control-flow hijacking on systems lacking sufficient runtime mitigations.

Attack Vector

The attack vector is network-based and requires the attacker to hold low-level privileges along with user interaction on the target. An authorized adversary sends specially crafted RRAS traffic to a vulnerable host. Once the malformed structure reaches the affected parser, the overflow occurs inside the RRAS service, granting code execution at the privilege level of that service. Because RRAS is commonly deployed on Windows Server edge devices providing VPN and routing functions, exploitation can establish a foothold in network-perimeter systems.

No public proof-of-concept exploit and no exploitation in the wild have been reported. Refer to the Microsoft CVE-2025-62452 Advisory for technical guidance.

Detection Methods for CVE-2025-62452

Indicators of Compromise

• Unexpected crashes or restarts of the RemoteAccess service (svchost.exe hosting RRAS) on Windows Server systems.
• Abnormal child processes spawned by the RRAS service host, particularly command interpreters such as cmd.exe or powershell.exe.
• Anomalous inbound traffic to RRAS-related ports including TCP 1723 (PPTP), UDP 500/4500 (IKE), and protocol 47 (GRE) from unexpected sources.

Detection Strategies

• Monitor Windows Event Logs for service crash entries (Event ID 7031, 7034) referencing RemoteAccess or RasMan.
• Apply behavioral detection rules that flag heap corruption indicators in svchost.exe instances hosting RRAS, such as Windows Error Reporting events tied to access violations.
• Correlate authenticated RRAS sessions with subsequent process creation events on the host to identify post-exploitation activity.

Monitoring Recommendations

• Centralize RRAS, authentication, and process telemetry into a SIEM or data lake for cross-source correlation.
• Track baseline RRAS service uptime and process behavior; investigate deviations promptly.
• Audit which accounts can authenticate to RRAS endpoints and alert on unusual authentication patterns preceding service instability.

How to Mitigate CVE-2025-62452

Immediate Actions Required

• Apply the Microsoft security update referenced in the Microsoft CVE-2025-62452 Advisory to all affected Windows client and Windows Server systems.
• Inventory hosts running RRAS and prioritize patching of internet-exposed VPN and routing servers.
• Restrict network access to RRAS endpoints to known management ranges until patches are deployed.

Patch Information

Microsoft has released updates for all supported affected versions, including Windows 10, Windows 11, and Windows Server 2008 through Windows Server 2025. Administrators should consult the Microsoft CVE-2025-62452 Advisory for the specific KB articles and deployment guidance applicable to each operating system version.

Workarounds

• Disable the Routing and Remote Access service on Windows Server hosts that do not require VPN or routing functionality.
• Enforce strict firewall rules limiting RRAS-related protocols (PPTP, L2TP/IPsec, SSTP, IKEv2) to trusted client networks.
• Require multi-factor authentication and conditional access for any account authorized to establish RRAS connections, reducing the population of users that can reach the vulnerable parser.

# Configuration example: Disable RRAS where not required (PowerShell, run as Administrator)
Stop-Service -Name RemoteAccess -Force
Set-Service -Name RemoteAccess -StartupType Disabled

# Restrict inbound RRAS-related traffic via Windows Firewall
New-NetFirewallRule -DisplayName "Block PPTP Inbound" -Direction Inbound -Protocol TCP -LocalPort 1723 -Action Block
New-NetFirewallRule -DisplayName "Block IKE Inbound" -Direction Inbound -Protocol UDP -LocalPort 500,4500 -Action Block