Overview
A critical stack-based buffer overflow vulnerability has been discovered in Circutor SGE-PLC1000 and SGE-PLC50 version 0.9.2. This vulnerability, identified as CVE-2025-11778, allows a remote attacker to potentially execute arbitrary code or cause a denial-of-service condition on the affected devices. The vulnerability resides within the TACACSPLUS implementation, specifically in the read_packet() function.
Technical Details
CVE-2025-11778 stems from insufficient bounds checking in the read_packet() function of the TACACSPLUS implementation within Circutor SGE-PLC1000/SGE-PLC50 v0.9.2. An attacker can exploit this vulnerability by sending a specially crafted TACACS+ packet containing an excessively long field. When the PLC processes this packet, the read_packet() function attempts to write data beyond the allocated buffer on the stack, leading to a buffer overflow. This can overwrite adjacent stack frames, potentially allowing the attacker to control the execution flow of the program.
CVSS Analysis
At the time of this writing, the CVSS score for CVE-2025-11778 is currently listed as N/A. A CVSS score will provide a standardized measure of the vulnerability’s severity. Once available, the CVSS score will reflect factors like attack vector, attack complexity, privileges required, user interaction, scope, confidentiality impact, integrity impact, and availability impact. We will update this article as soon as the CVSS score is published.
Possible Impact
The exploitation of CVE-2025-11778 could have severe consequences:
- Remote Code Execution (RCE): An attacker could potentially inject and execute arbitrary code on the PLC, gaining full control of the device.
- Denial of Service (DoS): The buffer overflow could crash the PLC, disrupting its operations and potentially affecting the entire industrial process it controls.
- Data Manipulation: An attacker could potentially manipulate data within the PLC’s memory, leading to incorrect control signals and potentially damaging equipment or compromising safety.
Given the role of PLCs in industrial control systems (ICS), a successful exploit could have significant real-world implications.
Mitigation and Patch Steps
The most effective mitigation strategy is to apply the vendor-provided patch as soon as it becomes available. Contact Circutor support or visit their website for the latest firmware updates.
In the interim, consider the following mitigation measures:
- Network Segmentation: Isolate the PLC network from the corporate network and the internet to limit the attack surface.
- Access Control: Implement strict access control policies to restrict access to the PLC to only authorized personnel and systems.
- Network Monitoring: Monitor network traffic for suspicious activity, such as unusual TACACS+ packets or communication patterns.
- Disable Unnecessary Services: If TACACS+ is not required, consider disabling the service to reduce the risk of exploitation.
Always follow the principle of least privilege and regularly review security configurations.