CVE-2024-49117: Windows Hyper-V RCE Vulnerability

CVE-2024-49117 Overview

CVE-2024-49117 is a remote code execution vulnerability affecting Windows Hyper-V, Microsoft's native hypervisor technology. This vulnerability allows an authenticated attacker on a guest virtual machine to execute arbitrary code on the underlying Hyper-V host system. The vulnerability stems from improper return of a status code (CWE-393), where the hypervisor fails to properly validate certain operations from guest VMs, potentially allowing malicious code to escape the virtual machine sandbox.

Critical Impact

A successful exploitation of this vulnerability could allow an attacker operating from within a guest VM to compromise the Hyper-V host, potentially affecting all other virtual machines running on that host and gaining complete control of the underlying infrastructure.

Affected Products

• Microsoft Windows 11 22H2
• Microsoft Windows 11 23H2
• Microsoft Windows 11 24H2
• Microsoft Windows Server 2022
• Microsoft Windows Server 2022 23H2
• Microsoft Windows Server 2025

Discovery Timeline

• December 12, 2024 - CVE-2024-49117 published to NVD
• January 14, 2025 - Last updated in NVD database

Technical Details for CVE-2024-49117

Vulnerability Analysis

This vulnerability affects the Windows Hyper-V virtualization component and represents a critical virtual machine escape scenario. The flaw allows an authenticated attacker with low privileges on a guest operating system to execute code on the Hyper-V host, effectively breaking the isolation boundary between virtual machines and the underlying hypervisor.

The vulnerability has a scope change impact, meaning successful exploitation affects resources beyond the vulnerable component's security scope. In this case, compromising the hypervisor from a guest VM impacts not only the host system but potentially all other virtual machines running on the same Hyper-V server. This makes the vulnerability particularly dangerous in multi-tenant cloud environments and virtualized data centers.

The attack requires local access to a guest VM and low-level privileges, but no user interaction is needed to trigger the exploit. Once executed, the attacker gains high-level access to confidentiality, integrity, and availability of the host system.

Root Cause

The vulnerability is classified under CWE-393 (Return of Wrong Status Code), indicating that the Hyper-V component improperly handles status codes during certain guest-to-host operations. This incorrect status handling creates a condition where the hypervisor may process malicious requests from a guest VM that should otherwise be rejected or handled differently.

When specific operations are performed within a guest VM, the hypervisor's failure to properly validate and return appropriate status codes allows for unexpected code paths to be triggered, ultimately leading to code execution in the host context.

Attack Vector

The attack vector for CVE-2024-49117 is local, requiring the attacker to have authenticated access to a guest virtual machine running on the target Hyper-V host. The attack complexity is low, meaning exploitation does not require specialized conditions or preparation.

The exploitation flow involves an attacker gaining initial access to a guest VM (through legitimate credentials, another vulnerability, or social engineering), then leveraging CVE-2024-49117 to escape the VM sandbox and execute code on the Hyper-V host. From this position, the attacker could:

• Access sensitive data on the host system
• Compromise other virtual machines on the same host
• Pivot to other systems in the network
• Install persistent backdoors at the hypervisor level
• Disrupt operations by manipulating or shutting down VMs

Detection Methods for CVE-2024-49117

Indicators of Compromise

• Unusual process activity originating from the vmwp.exe (Virtual Machine Worker Process) on Hyper-V hosts
• Unexpected memory access patterns or crashes in Hyper-V-related services
• Anomalous system calls or API invocations from guest VM contexts to host resources
• Suspicious modifications to Hyper-V configuration files or registry keys

Detection Strategies

• Monitor Windows Event Logs for Hyper-V operational events, particularly errors or warnings in the Microsoft-Windows-Hyper-V-Worker event channel
• Implement endpoint detection and response (EDR) monitoring on Hyper-V hosts to detect unusual behavior patterns
• Deploy SentinelOne agents on both guest VMs and Hyper-V hosts for comprehensive visibility across the virtualization stack
• Enable Windows Defender Credential Guard and monitor for bypass attempts

Monitoring Recommendations

• Configure centralized logging for all Hyper-V hosts with real-time alerting on critical events
• Establish baseline behavior for VM worker processes and alert on deviations
• Monitor network traffic between guest VMs and Hyper-V management interfaces for anomalies
• Regularly audit guest VM access and privileges to ensure only authorized users have access

How to Mitigate CVE-2024-49117

Immediate Actions Required

• Apply the Microsoft security update released in December 2024 immediately to all affected Hyper-V hosts
• Prioritize patching of production Hyper-V servers, especially those hosting critical workloads or multi-tenant environments
• Review and restrict guest VM access to only essential personnel
• Implement network segmentation to limit the blast radius of potential VM escape attacks

Patch Information

Microsoft has released security updates to address CVE-2024-49117 as part of their security update program. Detailed patch information and download links are available through the Microsoft Security Update Guide. Organizations should apply the appropriate update for their Windows version:

• Windows 11 22H2, 23H2, and 24H2
• Windows Server 2022 and Windows Server 2022 23H2
• Windows Server 2025

All patches should be tested in a non-production environment before deployment to production Hyper-V hosts, but given the severity of this vulnerability, expedited patching is recommended.

Workarounds

• If patching is not immediately possible, consider temporarily migrating critical VMs to patched hosts
• Restrict network access to Hyper-V hosts from untrusted networks
• Implement strict access controls on guest VMs to limit potential attack entry points
• Monitor affected systems closely for signs of exploitation until patches can be applied

# Verify Hyper-V security update installation status
Get-HotFix | Where-Object {$_.InstalledOn -gt (Get-Date).AddDays(-30)} | Format-Table -Property Description,HotFixID,InstalledOn

# Check Hyper-V service status
Get-Service vmms,vmcompute | Format-Table -Property Name,Status,StartType

# Review VM permissions
Get-VM | Get-VMSecurity | Format-Table -Property VMName,Shielded,EncryptStateAndVmMigrationTraffic