Overview
This article discusses a critical stack-based buffer overflow vulnerability, identified as CVE-2025-11785, affecting Circutor SGE-PLC1000 and SGE-PLC50 devices running version 9.0.2. This vulnerability allows a remote attacker to potentially execute arbitrary code on the affected device by providing an overly long input to a specific function.
Technical Details
The vulnerability resides within the ShowMeterPasswords() function of the Circutor SGE-PLC1000/SGE-PLC50 firmware. The core issue is an uncontrolled buffer copy via sprintf(). The GetParameter(meter) function retrieves user-supplied input for the ‘meter’ parameter. This input is then directly incorporated into a fixed-size buffer without proper size validation. Consequently, an attacker can provide an excessively large input for the ‘meter’ parameter, triggering a stack-based buffer overflow.
Specifically, the lack of input sanitization within the GetParameter() function when handling the ‘meter’ parameter creates an opportunity for malicious actors to overwrite memory on the stack. This overwrite can lead to denial of service, arbitrary code execution, or other undefined behavior depending on the specific memory locations overwritten and the attacker’s intentions.
CVSS Analysis
Currently, the CVSS score and severity for CVE-2025-11785 are listed as N/A. This is likely due to ongoing analysis or the delayed release of vulnerability scoring information. Given the nature of a stack-based buffer overflow in a PLC device, it is highly probable that the CVSS score will be rated as High or Critical once assigned, particularly if remote exploitation is feasible. We will update this section as soon as the official CVSS score is published.
Possible Impact
The potential impact of CVE-2025-11785 is significant, especially in industrial environments where these PLCs are deployed. Successful exploitation can lead to:
- Denial of Service (DoS): Crashing the PLC, disrupting industrial processes.
- Arbitrary Code Execution: Allowing attackers to execute malicious code on the PLC, potentially gaining control of the device and connected industrial equipment.
- Data Theft/Manipulation: Accessing sensitive data stored on the PLC or manipulating industrial processes for malicious purposes.
- Lateral Movement: Using the compromised PLC as a foothold to gain access to other systems on the network.
Mitigation or Patch Steps
To mitigate the risks associated with CVE-2025-11785, the following steps are recommended:
- Apply the Patch: Immediately apply the security patch released by Circutor once available. Check the Circutor website or contact their support for patch availability.
- Network Segmentation: Isolate the PLC network from the general IT network to limit the potential impact of a successful attack.
- Access Control: Implement strong access control measures to restrict access to the PLC and its management interface.
- Input Validation: If possible, implement input validation on the ‘meter’ parameter to limit the size and type of input accepted. (Note: This may require firmware modification and is not recommended without vendor support).
- Intrusion Detection Systems (IDS): Deploy IDS solutions to monitor network traffic for suspicious activity and potential exploitation attempts.
- Regular Firmware Updates: Keep the PLC firmware updated with the latest security patches to address known vulnerabilities.
