CVE-2025-64388: Web Server DOS Vulnerability

CVE-2025-64388 Overview

CVE-2025-64388 is a critical denial of service vulnerability affecting CIRCUTOR IoT industrial automation devices. The vulnerability allows remote attackers to crash the embedded web server through specially crafted protocol requests, potentially disrupting industrial monitoring and control operations.

Critical Impact

Remote attackers can exploit this vulnerability to cause a complete denial of service of the web server, affecting industrial control system availability without requiring authentication.

Affected Products

• CIRCUTOR IoT Industrial Converters and Gateways
• CIRCUTOR Industrial Automation Devices with Web Interface

Discovery Timeline

• 2025-10-31 - CVE-2025-64388 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2025-64388

Vulnerability Analysis

This vulnerability is classified under CWE-400 (Uncontrolled Resource Consumption), indicating that the web server fails to properly manage resource allocation when processing specific protocol requests. The flaw resides in the embedded web server component of CIRCUTOR IoT devices used in industrial automation environments.

The vulnerability is remotely exploitable over the network without requiring any authentication or user interaction. Successful exploitation results in complete unavailability of the web management interface, which can severely impact operational visibility and control capabilities in industrial environments. Given the nature of IoT and ICS devices, a denial of service attack could cascade into operational disruptions affecting downstream systems that rely on data from these converters and gateways.

Root Cause

The root cause stems from improper resource consumption controls (CWE-400) within the web server's request handling mechanism. The server fails to implement adequate safeguards against malformed or excessive protocol requests, allowing an attacker to exhaust available resources and crash the service. This represents a common vulnerability pattern in embedded systems where resource constraints often lead developers to omit robust input validation and rate limiting mechanisms.

Attack Vector

The attack is conducted over the network (AV:N) and requires no special privileges (PR:N), authentication, or user interaction (UI:N). An attacker can send specifically crafted requests to the web server's protocol interface to trigger the denial of service condition.

The attack exploits the protocol handling functionality of the embedded web server. By sending malformed or resource-intensive requests, an attacker can force the web server into an unresponsive state. Technical details regarding the specific protocol and request format can be found in the HackRTU 0-day Blog Analysis.

Detection Methods for CVE-2025-64388

Indicators of Compromise

• Unexpected web server crashes or restarts on CIRCUTOR IoT devices
• Abnormal network traffic patterns targeting the device's web interface ports
• Repeated connection attempts from unknown or suspicious IP addresses
• Log entries indicating malformed protocol requests or resource exhaustion errors

Detection Strategies

• Deploy network intrusion detection systems (IDS) to monitor for anomalous traffic patterns targeting CIRCUTOR device web interfaces
• Implement network segmentation and firewall rules to restrict access to industrial IoT device management interfaces
• Configure logging and alerting for web server availability on critical CIRCUTOR devices
• Monitor for unusual connection volumes or malformed request patterns in network traffic analysis

Monitoring Recommendations

• Establish baseline network behavior for CIRCUTOR IoT devices and alert on deviations
• Implement uptime monitoring with automated alerting for web server availability
• Deploy network traffic analysis tools capable of detecting protocol-level anomalies
• Review access logs periodically for unauthorized access attempts to device management interfaces

How to Mitigate CVE-2025-64388

Immediate Actions Required

• Restrict network access to CIRCUTOR IoT device web interfaces using firewalls and access control lists
• Isolate affected devices on a separate network segment with limited external connectivity
• Implement rate limiting at the network perimeter to mitigate request flooding attacks
• Monitor vendor channels for security patches and firmware updates

Patch Information

Organizations should monitor CIRCUTOR's official channels for security updates addressing this vulnerability. Additional security guidance may be available through the Thales Group Security Resource. Device information is available at the CIRCUTOR IoT Product Information page.

Workarounds

• Implement network-level access controls to limit web interface access to authorized management stations only
• Deploy a reverse proxy or web application firewall (WAF) in front of the device web interface if possible
• Disable the web interface entirely if not required for operational purposes
• Consider using out-of-band management solutions until a patch is available

Network segmentation and access control configuration example:

# Example firewall rule to restrict access to CIRCUTOR device web interface
# Allow only authorized management network (adjust IP ranges as needed)
iptables -A FORWARD -d <CIRCUTOR_DEVICE_IP> -p tcp --dport 80 -s <MGMT_NETWORK>/24 -j ACCEPT
iptables -A FORWARD -d <CIRCUTOR_DEVICE_IP> -p tcp --dport 443 -s <MGMT_NETWORK>/24 -j ACCEPT
iptables -A FORWARD -d <CIRCUTOR_DEVICE_IP> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <CIRCUTOR_DEVICE_IP> -p tcp --dport 443 -j DROP