CVE-2025-27474 Overview
CVE-2025-27474 is an information disclosure vulnerability affecting the Windows Routing and Remote Access Service (RRAS). The vulnerability stems from the use of an uninitialized resource within the RRAS component, which allows an unauthorized attacker to disclose sensitive information over a network. This vulnerability is classified under CWE-908 (Use of Uninitialized Resource).
RRAS is a critical Windows Server component that provides routing and remote access capabilities, including VPN connections, dial-up networking, and network address translation (NAT). Organizations relying on RRAS for their network infrastructure should prioritize assessment and remediation of this vulnerability.
Critical Impact
An unauthenticated attacker can exploit this vulnerability to disclose sensitive information over the network, potentially exposing credentials, configuration data, or other confidential information from affected Windows Server systems.
Affected Products
- Microsoft Windows Server 2008 SP2 (x64 and x86)
- Microsoft Windows Server 2008 R2 SP1 (x64)
- Microsoft Windows Server 2012
- Microsoft Windows Server 2012 R2
- Microsoft Windows Server 2016
- Microsoft Windows Server 2019
- Microsoft Windows Server 2022
- Microsoft Windows Server 2022 23H2
- Microsoft Windows Server 2025
Discovery Timeline
- 2025-04-08 - CVE-2025-27474 published to NVD
- 2025-07-08 - Last updated in NVD database
Technical Details for CVE-2025-27474
Vulnerability Analysis
This vulnerability exploits the improper handling of uninitialized resources within the Windows Routing and Remote Access Service. When RRAS processes certain network requests, it may inadvertently reference memory locations that contain residual data from previous operations. This uninitialized memory can contain sensitive information that gets exposed to attackers through crafted network requests.
The attack requires user interaction, meaning an attacker must entice a victim to perform an action, such as clicking a malicious link or opening a specially crafted file, for the vulnerability to be exploited. Once triggered, the attacker can access confidential data with high impact to confidentiality, though the vulnerability does not enable integrity modification or denial of service.
The network-based attack vector with low complexity makes this vulnerability particularly concerning for environments where RRAS is exposed to untrusted networks or where users may interact with potentially malicious content.
Root Cause
The root cause of CVE-2025-27474 lies in CWE-908: Use of Uninitialized Resource. The RRAS service fails to properly initialize memory or resource structures before use, resulting in the potential exposure of residual data from previous memory allocations. This type of vulnerability typically occurs when:
- Memory buffers are allocated but not zeroed before use
- Data structures are created without proper initialization of all fields
- Resource handles are reused without clearing previous state information
Attack Vector
The vulnerability is exploitable over the network without requiring authentication. An attacker can craft malicious network requests targeting the RRAS service to trigger the disclosure of uninitialized memory contents. The attack scenario involves:
- Identifying a Windows Server with RRAS enabled and accessible over the network
- Sending specially crafted requests designed to trigger the uninitialized resource condition
- Capturing the response containing leaked memory contents
- Analyzing the disclosed information for sensitive data such as memory addresses, credentials, or configuration details
The vulnerability requires user interaction, which may involve social engineering tactics to convince a user to access a malicious resource or perform a specific action that triggers the vulnerable code path.
Detection Methods for CVE-2025-27474
Indicators of Compromise
- Unusual network traffic patterns targeting RRAS services on TCP ports 1723 (PPTP) or UDP port 500/4500 (L2TP/IPsec)
- Anomalous memory access patterns or unexpected data in RRAS service responses
- Multiple failed or malformed connection attempts to RRAS from external sources
- Unexpected outbound data transfers from servers running RRAS
Detection Strategies
- Monitor Windows Security Event logs for unusual RRAS service activity or connection patterns
- Implement network intrusion detection rules to identify malformed RRAS protocol requests
- Deploy endpoint detection solutions capable of monitoring memory access patterns in the rasman.dll and related RRAS components
- Configure alerts for unusual data volumes in RRAS service responses
Monitoring Recommendations
- Enable verbose logging for the Routing and Remote Access Service
- Implement network segmentation to isolate RRAS servers from untrusted networks
- Deploy SentinelOne agents on all affected Windows Server systems to leverage behavioral AI detection capabilities
- Monitor for reconnaissance activities targeting RRAS endpoints
How to Mitigate CVE-2025-27474
Immediate Actions Required
- Apply the Microsoft security update for CVE-2025-27474 as soon as possible
- Review which servers have RRAS enabled and assess their exposure to untrusted networks
- Implement network-level access controls to restrict RRAS access to authorized users and networks only
- Consider disabling RRAS on servers where it is not required for business operations
Patch Information
Microsoft has released security updates to address this vulnerability. Administrators should consult the Microsoft Security Update Guide for CVE-2025-27474 for detailed patch information and download links specific to each affected Windows Server version.
The patches address the uninitialized resource issue by ensuring proper memory initialization before use within the RRAS service components. Organizations should test patches in a non-production environment before deploying to production systems, particularly for critical infrastructure servers.
Workarounds
- Disable the Routing and Remote Access Service on servers where it is not required using Set-Service RemoteAccess -StartupType Disabled
- Implement strict firewall rules to limit RRAS access to only trusted IP addresses and networks
- Deploy a VPN gateway or reverse proxy in front of RRAS servers to add an additional layer of authentication
- Use network segmentation to isolate RRAS servers in a dedicated security zone with enhanced monitoring
# Disable RRAS service if not needed (PowerShell)
Stop-Service RemoteAccess
Set-Service RemoteAccess -StartupType Disabled
# Verify RRAS service status
Get-Service RemoteAccess | Select-Object Name, Status, StartType
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
