CVE-2024-49119: Windows Server 2016 RCE Vulnerability

CVE-2024-49119 Overview

CVE-2024-49119 is a Remote Code Execution vulnerability affecting Windows Remote Desktop Services (RDS) across multiple Microsoft Windows Server versions. This vulnerability allows unauthenticated attackers to potentially execute arbitrary code on vulnerable systems over the network by exploiting flaws in how Remote Desktop Services handles certain requests, combining type confusion (CWE-843) and race condition (CWE-362) weaknesses.

Critical Impact

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code with elevated privileges on affected Windows Server systems running Remote Desktop Services, potentially leading to complete system compromise.

Affected Products

• Microsoft Windows Server 2016
• Microsoft Windows Server 2019
• Microsoft Windows Server 2022
• Microsoft Windows Server 2022 23H2
• Microsoft Windows Server 2025

Discovery Timeline

• 2024-12-12 - CVE-2024-49119 published to NVD
• 2025-01-14 - Last updated in NVD database

Technical Details for CVE-2024-49119

Vulnerability Analysis

This vulnerability exists within Windows Remote Desktop Services (RDS), a critical component that enables remote access to Windows Server systems. The flaw combines two distinct weakness types: Type Confusion (CWE-843) and Race Condition (CWE-362).

The Type Confusion weakness occurs when the RDS component processes data under incorrect type assumptions, allowing an attacker to manipulate program execution flow. When combined with the Race Condition weakness, a timing window exists where concurrent operations may interact in an unsafe manner, creating an exploitable state.

Exploitation requires network access to the Remote Desktop Services port (typically TCP 3389) but does not require user authentication or interaction, making it particularly concerning for internet-facing RDS deployments. The high complexity of exploitation, however, suggests that reliable attacks would require precise timing and multiple attempts.

Root Cause

The root cause of CVE-2024-49119 stems from two interrelated weaknesses in Windows Remote Desktop Services:

1. Type Confusion (CWE-843): The RDS component accesses resources using an incompatible type, which can lead to incorrect memory access and potentially allow code execution when the program interprets data as a different type than intended.

2. Race Condition (CWE-362): Concurrent execution using shared resources creates a timing vulnerability where proper synchronization is not maintained, allowing an attacker to exploit the window between check and use operations.

Attack Vector

The attack vector for this vulnerability is network-based, requiring no user authentication or interaction. An attacker would need to:

1. Identify a target Windows Server with Remote Desktop Services enabled and accessible over the network
2. Send specially crafted requests to the RDS service designed to trigger the type confusion condition
3. Exploit the race condition timing window to achieve code execution
4. If successful, gain the ability to execute arbitrary code with the privileges of the RDS service

The vulnerability mechanism involves exploiting the type confusion and race condition weaknesses in the Remote Desktop Services component. For detailed technical information, refer to the Microsoft Security Advisory.

Detection Methods for CVE-2024-49119

Indicators of Compromise

• Unusual or unexpected network traffic patterns targeting TCP port 3389 (RDP)
• Anomalous Remote Desktop Services crashes or restarts
• Unexpected process spawning from svchost.exe processes hosting RDS components
• Memory access violations or type confusion errors in Windows Event Logs related to termsrv.dll

Detection Strategies

• Monitor Remote Desktop Services for unexpected service restarts or crashes that may indicate exploitation attempts
• Implement network-level detection for malformed RDP protocol packets or unusual connection patterns
• Enable Windows Defender Credential Guard and monitor for suspicious RDS-related activities
• Deploy endpoint detection and response (EDR) solutions to identify anomalous behavior from RDS processes

Monitoring Recommendations

• Enable verbose logging for Remote Desktop Services and Terminal Services components
• Monitor Windows Security Event Log for Event IDs related to RDP authentication and connection attempts
• Implement network flow analysis on RDP traffic to detect unusual connection patterns or payload sizes
• Configure alerts for multiple rapid connection attempts or protocol anomalies on port 3389

How to Mitigate CVE-2024-49119

Immediate Actions Required

• Apply the Microsoft security update for CVE-2024-49119 immediately on all affected Windows Server systems
• Restrict network access to Remote Desktop Services to only trusted IP addresses using Windows Firewall or network-level access controls
• Consider disabling Remote Desktop Services on systems where it is not required
• Implement Network Level Authentication (NLA) to add an additional layer of protection

Patch Information

Microsoft has released security updates to address this vulnerability. Administrators should apply the appropriate update for their Windows Server version through Windows Update, WSUS, or manual download from the Microsoft Update Catalog. For detailed patch information and download links, refer to the Microsoft Security Response Center advisory for CVE-2024-49119.

Workarounds

• Disable Remote Desktop Services on servers that do not require remote access functionality
• Implement network segmentation to isolate RDS servers from untrusted networks
• Use a VPN or Remote Desktop Gateway to limit direct RDP exposure to the internet
• Enable Network Level Authentication (NLA) to require authentication before a full RDP connection is established

# Disable Remote Desktop Services if not required
Set-Service -Name "TermService" -StartupType Disabled
Stop-Service -Name "TermService" -Force

# Enable Network Level Authentication (NLA) via Registry
Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp" -Name "UserAuthentication" -Value 1

# Restrict RDP access to specific IP ranges using Windows Firewall
New-NetFirewallRule -DisplayName "Restrict RDP Access" -Direction Inbound -Protocol TCP -LocalPort 3389 -RemoteAddress "10.0.0.0/8,192.168.0.0/16" -Action Allow
Set-NetFirewallRule -DisplayName "Remote Desktop - User Mode (TCP-In)" -Enabled False