Overview
CVE-2025-11781 describes a critical security vulnerability affecting Circutor SGE-PLC1000 and SGE-PLC50 programmable logic controllers (PLCs) running firmware version 9.0.2. The vulnerability stems from the use of hardcoded cryptographic keys within the firmware. This allows an attacker with local access to the device to extract the key and forge valid firmware update packages, effectively bypassing all access controls and gaining full administrative privileges over the PLC.
Technical Details
The affected firmware version 9.0.2 of the Circutor SGE-PLC1000/SGE-PLC50 contains a static, hardcoded authentication key. This key is used to verify the authenticity and integrity of firmware update packages. An attacker with local access to the device (e.g., physical access or access via a compromised network segment) can extract this key through various methods, including:
- Firmware Image Analysis: Analyzing the firmware image file (often obtainable from the vendor’s website or through other means) to locate the hardcoded key.
- Memory Dump: Performing a memory dump of the PLC’s memory while it is running, and searching for the key within the memory contents.
Once the attacker possesses the hardcoded key, they can create malicious firmware update packages that the PLC will accept as legitimate. This allows them to inject arbitrary code, modify PLC configuration, and completely compromise the device’s functionality.
CVSS Analysis
Due to the availability of the CVSS score being N/A, a formal CVSS analysis is unavailable. However, given the nature of the vulnerability, a high CVSS score is likely. A successful exploit allows for complete compromise of the PLC, potentially leading to significant disruptions in industrial control systems (ICS) and SCADA environments.
This is because an attacker exploiting this vulnerability gains full administrative control, enabling them to:
- Modify PLC logic, leading to incorrect or unsafe operation of controlled processes.
- Steal sensitive data from the PLC.
- Use the compromised PLC as a launchpad for further attacks on the network.
- Completely brick the PLC, causing downtime and financial losses.
Possible Impact
The potential impact of CVE-2025-11781 is significant, especially in industrial settings where these PLCs are used. A successful exploitation could lead to:
- Process Disruption: Compromised PLCs could disrupt critical industrial processes, leading to production downtime, equipment damage, and financial losses.
- Safety Hazards: Manipulated PLC logic could create unsafe operating conditions, potentially causing accidents, injuries, or even fatalities.
- Data Breaches: Sensitive data stored on or transmitted by the PLC could be stolen, leading to intellectual property theft or other security breaches.
- Reputational Damage: A successful attack could damage the reputation of the affected organization.
Mitigation or Patch Steps
The primary mitigation step is to apply the security patch or firmware update provided by Circutor. Users should:
- Check for Updates: Regularly check the Circutor website for security advisories and firmware updates for the SGE-PLC1000/SGE-PLC50.
- Apply the Patch: Immediately apply any available security patches or firmware updates that address CVE-2025-11781.
- Network Segmentation: Implement network segmentation to isolate PLCs from other parts of the network, limiting the potential impact of a successful attack.
- Access Control: Implement strong access control measures to restrict physical and network access to the PLCs.
- Monitoring: Implement intrusion detection and monitoring systems to detect suspicious activity on the network and on the PLCs.
