CVE-2025-11787: Circutor SGE-PLC1000 RCE Vulnerability

CVE-2025-11787 Overview

CVE-2025-11787 is a high-severity command injection vulnerability affecting Circutor SGE-PLC1000 and SGE-PLC50 programmable logic controllers running firmware version 9.0.2. The vulnerability exists in the operating system through the GetDNS(), CheckPing(), and TraceRoute() functions, allowing attackers to inject and execute arbitrary operating system commands.

This vulnerability is classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command), a critical weakness that can lead to complete system compromise. With a CVSS 4.0 score of 8.5 (HIGH), this vulnerability poses a significant risk to industrial control environments where these PLCs are deployed.

Critical Impact

Network-accessible command injection in industrial PLCs can lead to complete device takeover, manipulation of industrial processes, lateral movement within OT networks, and potential safety incidents in critical infrastructure environments.

Affected Products

• Circutor SGE-PLC1000 Firmware version 9.0.2
• Circutor SGE-PLC1000 Hardware
• Circutor SGE-PLC50 Firmware version 9.0.2
• Circutor SGE-PLC50 Hardware

Discovery Timeline

• December 2, 2025 - CVE-2025-11787 published to NVD
• December 3, 2025 - Last updated in NVD database

Technical Details for CVE-2025-11787

Vulnerability Analysis

The command injection vulnerability resides in three network diagnostic functions within the Circutor SGE-PLC1000 and SGE-PLC50 firmware: GetDNS(), CheckPing(), and TraceRoute(). These functions are commonly used for network troubleshooting but fail to properly sanitize user-supplied input before passing it to the underlying operating system shell.

The CVSS 4.0 vector string CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N indicates:

• Attack Vector (AV:N): The vulnerability is exploitable over the network
• Attack Complexity (AC:L): No specialized conditions required for exploitation
• Privileges Required (PR:L): Low-level authentication is needed
• User Interaction (UI:A): Some user interaction may be required
• Impact: High confidentiality, integrity, and availability impact on the vulnerable system

The EPSS score of 0.218% places this vulnerability at the 44.46th percentile, indicating a moderate probability of exploitation in the wild.

Root Cause

The root cause of CVE-2025-11787 is improper input validation and sanitization in the network diagnostic functions. When user input is passed to GetDNS(), CheckPing(), or TraceRoute(), the firmware fails to properly escape or validate shell metacharacters before constructing and executing system commands.

These functions likely construct OS commands by concatenating user-supplied hostnames or IP addresses directly into command strings that are then executed via system shell calls. Without proper validation, attackers can inject shell metacharacters such as semicolons (;), pipes (|), or command substitution sequences to execute arbitrary commands.

Attack Vector

The attack vector for this vulnerability involves network-based exploitation targeting the web management interface or API endpoints of the affected PLCs. An attacker with low-level authentication credentials can abuse the vulnerable diagnostic functions by injecting malicious payloads into parameters expected to contain hostnames or IP addresses.

For example, instead of providing a legitimate hostname to the CheckPing() function, an attacker could supply input containing shell command separators followed by malicious commands. The vulnerable function would then execute both the intended ping operation and the injected malicious commands with the privileges of the PLC's operating system.

Since no verified code examples are available for this vulnerability, security teams should refer to the INCIBE-CERT advisory at https://www.incibe.es/en/incibe-cert/notices/aviso-sci/multiple-vulnerabilities-circutor-products-0 for additional technical details.

Detection Methods for CVE-2025-11787

Indicators of Compromise

• Unusual network diagnostic requests containing shell metacharacters (;, |, &, $(), backticks)
• Unexpected outbound connections from PLC devices to external IP addresses
• Anomalous process execution on PLC systems outside normal operational patterns
• Web interface logs showing requests to diagnostic endpoints with malformed parameters
• Authentication attempts followed by immediate access to diagnostic functions

Detection Strategies

Organizations should implement network-based detection to identify potential exploitation attempts:

1. Web Application Firewall (WAF) Rules: Deploy rules to detect and block requests containing OS command injection patterns targeting the GetDNS, CheckPing, and TraceRoute endpoints.

2. Network Traffic Analysis: Monitor HTTP/HTTPS traffic to PLC management interfaces for parameters containing shell metacharacters or command injection signatures.

3. Log Analysis: Review PLC access logs for unusual patterns of diagnostic function usage, particularly from unexpected source IPs or during non-maintenance windows.

4. Behavioral Monitoring: Establish baselines for normal PLC network behavior and alert on deviations such as unexpected outbound connections or DNS queries.

Monitoring Recommendations

Implement continuous monitoring of Circutor PLC devices with focus on:

• All HTTP/HTTPS traffic to and from PLC management interfaces
• System-level command execution logs if available through PLC diagnostics
• Network flows originating from PLC devices to detect potential reverse shells or data exfiltration
• Authentication events and subsequent actions on PLC management portals
• Firmware integrity checks to detect unauthorized modifications

SentinelOne Singularity provides comprehensive network detection capabilities that can identify command injection attempts and anomalous behavior patterns associated with this vulnerability class in OT environments.

How to Mitigate CVE-2025-11787

Immediate Actions Required

• Restrict network access to PLC management interfaces using firewalls and network segmentation
• Implement strict access control lists (ACLs) limiting which IP addresses can reach PLC web interfaces
• Disable or restrict access to diagnostic functions (GetDNS, CheckPing, TraceRoute) if not operationally required
• Enable logging for all authentication and diagnostic function usage
• Monitor for indicators of compromise outlined above

Patch Information

Organizations should monitor Circutor's official channels for firmware updates addressing CVE-2025-11787. Until patches are available, implement the recommended workarounds and compensating controls.

For additional details and updates, refer to the INCIBE-CERT security advisory: https://www.incibe.es/en/incibe-cert/notices/aviso-sci/multiple-vulnerabilities-circutor-products-0

Workarounds

In the absence of an official patch, implement the following compensating controls:

Network segmentation is critical for protecting vulnerable PLCs:

# Example firewall rules to restrict PLC management access
# Allow management access only from trusted admin subnet
iptables -A INPUT -s 10.10.10.0/24 -d PLC_IP -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -s 10.10.10.0/24 -d PLC_IP -p tcp --dport 443 -j ACCEPT

# Block all other management access
iptables -A INPUT -d PLC_IP -p tcp --dport 80 -j DROP
iptables -A INPUT -d PLC_IP -p tcp --dport 443 -j DROP

Additional hardening measures include:

• Place all affected PLCs behind a properly configured industrial demilitarized zone (DMZ)
• Implement multi-factor authentication where supported
• Conduct regular security audits of PLC configurations and access logs
• Consider deploying an industrial-focused intrusion detection system (IDS) to monitor for exploitation attempts