CVE-2025-21307: Windows 10 1507 RMCAST RCE Vulnerability

CVE-2025-21307 Overview

The CVE-2025-21307 vulnerability exists in the Windows Reliable Multicast Transport Driver (RMCAST), enabling remote code execution. This flaw can be exploited by an attacker over the network without requiring any user interaction, posing a significant threat to affected systems.

Critical Impact
This vulnerability can allow an attacker to execute arbitrary code on the vulnerable system, potentially leading to complete system compromise.

Affected Products

Microsoft Windows 10 1507
Microsoft Windows 10 1607
Microsoft Windows 10 1809

Discovery Timeline

Not Available - Vulnerability discovered by Not Available
Not Available - Responsible disclosure to Microsoft
Not Available - CVE CVE-2025-21307 assigned
Not Available - Microsoft releases security patch
2025-01-14 - CVE CVE-2025-21307 published to NVD
2025-01-24 - Last updated in NVD database

Technical Details for CVE-2025-21307

Vulnerability Analysis

The vulnerability arises from improper handling of multicast network packets by the RMCAST driver. This could lead to memory corruption, allowing an attacker to execute arbitrary code at the system level.

Root Cause

The root cause is a use-after-free condition within the RMCAST driver when processing specially crafted network packets.

Attack Vector

This vulnerability is exploitable over the network, allowing remote attackers to send specially crafted packets to target systems.

// Example exploitation code (sanitized)
#include <stdio.h>
#include <stdlib.h>

void exploit() {
    char *packet = malloc(1024);
    // Fictitious packet crafting to demonstrate potential overflow
    memset(packet, 'A', 1024);
    // Send crafted packet to vulnerable listener
}

Detection Methods for CVE-2025-21307

Indicators of Compromise

Unexpected network traffic on RMCAST ports
System crashes or unexpected reboots
Unauthorized code execution logs

Detection Strategies

Implement network monitoring tools to detect unusual multicast packet transmissions triggering RMCAST functionality. Use endpoint detection and response (EDR) solutions to capture system anomalies indicative of memory corruption.

Monitoring Recommendations

Use SentinelOne’s ActiveEDR capabilities to monitor behavioral anomalies and detect unauthorized code execution stemming from network-based attacks.

How to Mitigate CVE-2025-21307

Immediate Actions Required

Disable RMCAST functionality if not required
Implement strict network segmentation to limit multicast traffic
Regularly apply vendor-recommended patches

Patch Information

Ensure Microsoft update CVE-2025-21307 is applied, containing fixes for the vulnerability.

Workarounds

Disabling unnecessary multicast features and configuring network firewalls to block suspicious multicast packets can mitigate exploitation potential. Always keep systems updated with the latest security patches.

bash

# Configuration example
echo "net.ipv4.icmp_echo_ignore_broadcasts = 1" >> /etc/sysctl.conf
sysctl -p