Windows RRAS Under Siege: Unpacking CVE-2025-49674's Heap Overflow Threat

Introduction

Windows Routing and Remote Access Service (RRAS), a critical component managing VPN and network routing, faces a severe threat in the form of CVE-2025-49674—a heap-based buffer overflow vulnerability. With a CVSS score of 8.8, this flaw enables remote attackers to execute arbitrary code without authentication, potentially compromising entire networks and critical infrastructure.

Technical Information

CVE-2025-49674 is classified as a heap-based buffer overflow (CWE-122), resulting from improper memory handling within the RRAS component. Attackers exploit this vulnerability by sending specially crafted network packets designed to overflow memory buffers. This overflow corrupts adjacent heap structures, allowing attackers to execute arbitrary code with SYSTEM-level privileges.

Attack Vectors and Exploitation Methods

Remote Exploitation: Attackers require no authentication or user interaction, significantly increasing the ease of exploitation.
Privilege Escalation: Successful exploitation grants attackers full control over the affected system, enabling further lateral movement, data exfiltration, or ransomware deployment.

Affected Systems and Versions

The following Microsoft Windows versions are specifically affected:

Windows Server 2012 R2
Windows Server 2016
Windows Server 2019
Windows Server 2022
Windows Server 2025
Windows 11 Version 24H2

Systems running RRAS in default or custom configurations are vulnerable.

Patch Information

Microsoft has released a security update addressing CVE-2025-49674. The patch modifies RRAS to properly validate input data and manage memory allocations, preventing buffer overflows. By implementing stricter bounds checking and input validation, the update ensures data exceeding allocated buffer sizes is not processed, mitigating the risk of arbitrary code execution.

Administrators should immediately apply this security update via Windows Update or the Microsoft Update Catalog to protect systems from potential exploitation.

Vendor Security History

Microsoft regularly addresses vulnerabilities through its monthly Patch Tuesday updates. However, RRAS has historically faced repeated vulnerabilities, indicating ongoing security challenges in legacy components. CVE-2025-49674 is part of a larger update addressing 130 vulnerabilities, emphasizing Microsoft's proactive yet ongoing struggle with securing older services.

Threat Intelligence

Currently, there is no evidence of active exploitation of CVE-2025-49674. Nevertheless, given its high exploitability and remote attack vector, exploitation attempts are likely imminent. Organizations should prioritize patching and closely monitor RRAS services for suspicious activities.

References

Prompt action and vigilance are essential to safeguard your infrastructure from this critical vulnerability.

Source: This report was created using AI

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