CVE-2024-30070 Overview
CVE-2024-30070 is a denial of service vulnerability affecting the Dynamic Host Configuration Protocol (DHCP) Server Service in multiple versions of Microsoft Windows Server. The flaw is rooted in an integer underflow condition [CWE-191] within the DHCP service. Remote, unauthenticated attackers can send crafted network traffic to a vulnerable DHCP server and trigger conditions that disrupt service availability. Microsoft addressed the issue through its June 2024 security update cycle. The vulnerability impacts core network infrastructure components used to assign IP addresses across enterprise environments.
Critical Impact
Unauthenticated attackers on the network can disrupt DHCP services on Windows Server 2012, 2016, and 2019, breaking IP address allocation for connected clients.
Affected Products
- Microsoft Windows Server 2012 (including R2)
- Microsoft Windows Server 2016
- Microsoft Windows Server 2019
Discovery Timeline
- 2024-06-11 - CVE-2024-30070 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-30070
Vulnerability Analysis
The vulnerability resides in the Windows DHCP Server Service, which handles client requests for IP address leases and configuration parameters. The service processes DHCP message fields during request parsing. An integer underflow condition occurs when specific values within a DHCP message cause arithmetic operations to wrap below zero. This corrupts subsequent length calculations and processing logic. The result is a denial of service that interrupts the DHCP server's ability to respond to legitimate client requests. Network clients relying on DHCP for IP allocation lose connectivity until the service is restored.
Root Cause
The root cause is an integer underflow [CWE-191] in the DHCP Server Service code path that handles inbound DHCP messages. The service performs arithmetic on attacker-influenced fields without validating that operands remain within expected bounds. When the calculation underflows, downstream logic operates on invalid sizes or offsets, causing the service to crash or stop processing requests.
Attack Vector
The attack vector is network-based and requires no authentication or user interaction. An attacker with network reachability to UDP port 67 on a vulnerable DHCP server can send crafted DHCP packets to trigger the underflow. Because DHCP traffic typically traverses local broadcast domains, any host on a network segment served by the DHCP server can deliver the malicious traffic. Internal threat actors and compromised endpoints represent the most realistic exploitation scenarios for this issue.
No verified proof-of-concept code is publicly available. Refer to the Microsoft Security Update CVE-2024-30070 advisory for vendor-supplied technical details.
Detection Methods for CVE-2024-30070
Indicators of Compromise
- Unexpected termination or repeated restarts of the DHCPServer service on Windows Server hosts.
- Spikes in malformed or oversized DHCP request packets targeting UDP port 67.
- DHCP clients failing to obtain or renew leases across normally healthy network segments.
- Windows Event Log entries indicating DHCP Server service crashes or unhandled exceptions.
Detection Strategies
- Monitor Windows Event Log channels Microsoft-Windows-DHCP-Server/Operational and System for service stop, crash, and recovery events.
- Deploy network detection rules that flag anomalous DHCP message field lengths and option structures.
- Correlate sudden drops in successful DHCP lease grants with concurrent server-side service faults.
Monitoring Recommendations
- Enable centralized logging of DHCP server health metrics and forward events to a SIEM for correlation.
- Track baseline DHCP request volume per subnet and alert on statistical deviations.
- Use endpoint protection telemetry on DHCP servers to capture process crashes and behavioral anomalies tied to dhcpserver.exe.
How to Mitigate CVE-2024-30070
Immediate Actions Required
- Apply the June 2024 Microsoft security updates to all affected Windows Server 2012, 2016, and 2019 systems hosting the DHCP role.
- Inventory all servers running the DHCP Server Service and prioritize patching of internet-adjacent and high-availability deployments.
- Restrict DHCP traffic to authorized network segments using VLAN segmentation and switch-level DHCP snooping.
- Validate DHCP server redundancy configurations so failover partners remain available during patch rollouts.
Patch Information
Microsoft has released security updates addressing this vulnerability. Administrators should consult the Microsoft Security Update CVE-2024-30070 advisory for the specific Knowledge Base article and update package corresponding to each Windows Server version in use. Apply the updates through Windows Update, WSUS, or the Microsoft Update Catalog.
Workarounds
- Enable DHCP snooping on managed switches to filter untrusted DHCP traffic before it reaches the server.
- Implement strict host-based firewall rules restricting UDP/67 inbound traffic to known client subnets.
- Configure DHCP failover or split-scope deployments to maintain lease availability if a primary server becomes unresponsive.
- Monitor and automatically restart the DHCP Server Service to reduce outage duration if the service crashes.
# Verify DHCP service status and recent crash events on Windows Server
Get-Service -Name DHCPServer
Get-WinEvent -LogName System -MaxEvents 50 | Where-Object { $_.ProviderName -like '*DHCP*' }
# Configure automatic recovery for the DHCP Server Service
sc.exe failure DHCPServer reset= 86400 actions= restart/60000/restart/60000/restart/60000
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
