CVE-2024-21416: Windows 10 1809 TCP/IP RCE Vulnerability

CVE-2024-21416 Overview

CVE-2024-21416 is a critical remote code execution vulnerability affecting the Windows TCP/IP stack. This vulnerability allows unauthenticated remote attackers to execute arbitrary code on affected Windows systems by sending specially crafted network packets. The flaw resides in the core networking component of Windows, making it particularly dangerous as it can be exploited over the network without any user interaction or authentication.

Critical Impact

This vulnerability enables remote code execution at the kernel level through malicious network traffic, potentially allowing complete system compromise without authentication or user interaction.

Affected Products

• Microsoft Windows 10 1809
• Microsoft Windows 10 21H2
• Microsoft Windows 10 22H2
• Microsoft Windows 11 21H2
• Microsoft Windows 11 22H2
• Microsoft Windows 11 23H2
• Microsoft Windows 11 24H2
• Microsoft Windows Server 2019
• Microsoft Windows Server 2022
• Microsoft Windows Server 2022 23H2

Discovery Timeline

• September 10, 2024 - CVE-2024-21416 published to NVD
• September 20, 2024 - Last updated in NVD database

Technical Details for CVE-2024-21416

Vulnerability Analysis

CVE-2024-21416 is classified as a Heap-based Buffer Overflow (CWE-122) vulnerability in the Windows TCP/IP networking stack. The flaw occurs in the kernel-mode TCP/IP driver (tcpip.sys), which handles all network protocol processing at the operating system level. When processing certain malformed network packets, the TCP/IP stack fails to properly validate buffer boundaries, allowing an attacker to write data beyond the allocated heap buffer. This memory corruption in kernel space can be leveraged to execute arbitrary code with SYSTEM privileges.

The vulnerability is particularly severe because the TCP/IP stack operates at the kernel level and processes all incoming network traffic, meaning exploitation requires no authentication, no user interaction, and can be triggered remotely by any system capable of sending network packets to the target. Successful exploitation grants the attacker complete control over the affected system with the highest privilege level.

Root Cause

The root cause of CVE-2024-21416 is a heap-based buffer overflow (CWE-122) in the Windows TCP/IP networking stack. The vulnerability stems from improper bounds checking when processing network packet data. When the TCP/IP driver allocates a heap buffer for incoming packet data but fails to validate that the data being copied fits within the allocated buffer size, memory corruption occurs. This allows an attacker to overwrite adjacent heap memory structures, potentially including function pointers or other critical kernel data structures.

Attack Vector

The attack vector for CVE-2024-21416 is network-based, requiring the attacker to send specially crafted TCP/IP packets to a vulnerable Windows system. The attack can be executed remotely from anywhere on the network or internet where the attacker can establish network connectivity to the target. Key characteristics of the attack include:

• No Authentication Required: The attacker does not need any credentials or authenticated session
• No User Interaction: Exploitation occurs automatically when the malicious packet is processed
• Kernel-Level Execution: Successful exploitation results in code execution in kernel mode with SYSTEM privileges

The vulnerability can be triggered through various network services listening on the target system, making any internet-facing Windows server particularly vulnerable.

Detection Methods for CVE-2024-21416

Indicators of Compromise

• Unexpected system crashes or Blue Screen of Death (BSOD) events with bugchecks related to tcpip.sys
• Anomalous kernel memory access patterns or heap corruption indicators in crash dumps
• Unusual network traffic patterns with malformed TCP/IP packet structures
• Evidence of unauthorized code execution or persistence mechanisms following network exposure

Detection Strategies

• Deploy network intrusion detection systems (NIDS) with signatures for anomalous TCP/IP packet structures targeting Windows systems
• Monitor Windows Event Logs for unexpected system crashes, particularly those involving kernel-mode drivers
• Implement endpoint detection and response (EDR) solutions like SentinelOne to detect exploitation attempts and post-exploitation activity
• Analyze crash dumps for evidence of heap corruption in tcpip.sys or related networking components

Monitoring Recommendations

• Enable detailed Windows kernel crash dump collection for forensic analysis of potential exploitation attempts
• Configure network monitoring to flag unusual packet sizes, malformed headers, or suspicious TCP/IP anomalies
• Deploy SentinelOne Singularity platform for real-time behavioral detection of kernel-level exploitation and privilege escalation attempts
• Establish baseline network traffic patterns to identify deviations that may indicate exploitation activity

How to Mitigate CVE-2024-21416

Immediate Actions Required

• Apply the Microsoft security update immediately to all affected Windows systems, prioritizing internet-facing servers
• Implement network segmentation to limit exposure of vulnerable systems until patching is complete
• Review firewall rules to restrict unnecessary inbound network traffic to affected systems
• Enable SentinelOne Singularity endpoint protection for runtime detection and prevention of exploitation attempts

Patch Information

Microsoft has released security updates to address CVE-2024-21416 as part of the September 2024 Patch Tuesday release. Administrators should apply the appropriate cumulative update for their Windows version immediately. Detailed patch information and download links are available in the Microsoft Security Update Guide.

Organizations should prioritize patching based on system exposure:

1. Internet-facing Windows servers
2. Domain controllers and critical infrastructure
3. Internal servers and workstations

Workarounds

• Implement strict network segmentation and firewall rules to limit inbound network traffic to only necessary services and trusted sources
• Consider deploying network-level filtering appliances capable of deep packet inspection to block malformed TCP/IP packets
• Enable Windows Firewall with restrictive inbound rules on vulnerable systems pending patch deployment
• Utilize SentinelOne's Ranger network visibility to identify and isolate unpatched vulnerable systems

# Enable Windows Firewall and restrict inbound connections
netsh advfirewall set allprofiles state on
netsh advfirewall set allprofiles firewallpolicy blockinbound,allowoutbound

# Block all inbound connections except those specifically allowed
netsh advfirewall firewall set rule group="Remote Desktop" new enable=no