Heap Overflow in Circutor SGE-PLC1000/SGE-PLC50 (CVE-2025-11788): A Critical Vulnerability Analysis

Overview

This article provides a detailed analysis of CVE-2025-11788, a heap-based buffer overflow vulnerability discovered in Circutor SGE-PLC1000/SGE-PLC50 version 9.0.2. This vulnerability allows a remote attacker to potentially execute arbitrary code or cause a denial-of-service (DoS) condition by providing a crafted input to the device.

Technical Details

The vulnerability resides within the ShowSupervisorParameters() function. The core issue stems from an unbounded sprintf() call when handling user input obtained through the GetParameter(meter) function. Specifically:

• The GetParameter(meter) function retrieves user-supplied input associated with the ‘meter’ parameter.
• This input is then directly incorporated into a fixed-size buffer using sprintf() within the ShowSupervisorParameters() function.
• Crucially, there is no size validation performed on the input before it is copied into the buffer.

An attacker can exploit this by providing an excessively large input string for the ‘meter’ parameter. When sprintf() attempts to write this oversized input into the fixed-size buffer, it overflows the buffer’s boundaries, potentially overwriting adjacent memory on the heap. This heap corruption can then be leveraged for code execution or to crash the device.

CVSS Analysis

At the time of writing, a CVSS score has not been officially assigned to CVE-2025-11788. However, based on the technical details and the potential for remote code execution, a high severity score is likely. We anticipate a score in the range of 8.0-9.0, considering the potential for significant impact and relatively low attack complexity.

Factors influencing this potential score include:

• Attack Vector: Network (remote exploitation)
• Attack Complexity: Low to Medium (requires crafting a specific input but likely no authentication bypass)
• Privileges Required: None (potentially exploitable without authentication, depending on the specific implementation)
• User Interaction: None (likely no user interaction required)
• Scope: Changed (exploitation could allow for control of the PLC)
• Confidentiality Impact: High (potential to access sensitive data)
• Integrity Impact: High (potential to modify PLC configuration and behavior)
• Availability Impact: High (potential for denial-of-service or complete system compromise)

Disclaimer: This is an estimated CVSS score based on the available information. The official CVSS score, once released, should be considered the authoritative rating.

Possible Impact

Successful exploitation of CVE-2025-11788 can have severe consequences:

• Remote Code Execution (RCE): An attacker could execute arbitrary code on the PLC, potentially taking complete control of the device and the industrial processes it controls.
• Denial-of-Service (DoS): Overwriting critical memory regions can cause the PLC to crash or become unresponsive, disrupting industrial operations.
• Data Manipulation: Attackers could alter configuration settings, manipulate sensor readings, or inject malicious data into the industrial control system, leading to incorrect operations and potential safety hazards.
• Lateral Movement: A compromised PLC could be used as a stepping stone to attack other systems within the industrial network.

Mitigation or Patch Steps

Circutor has likely released or is preparing to release a patch to address this vulnerability. The following steps are recommended:

1. Apply the Patch: Immediately apply the latest firmware update or patch provided by Circutor for the SGE-PLC1000/SGE-PLC50. Refer to Circutor’s official website for the latest updates.
2. Network Segmentation: Isolate the PLC network from the general IT network to limit the potential impact of a successful attack.
3. Access Control: Implement strict access control policies to limit who can access and modify PLC configurations.
4. Input Validation: While a patch is the primary solution, consider implementing input validation at the network level (e.g., using a firewall or intrusion detection system) to filter out excessively long ‘meter’ parameter values.
5. Monitor Network Traffic: Continuously monitor network traffic for suspicious activity that might indicate exploitation attempts.

References

INCIBE-CERT Advisory: Multiple vulnerabilities in Circutor products