Full Report
[Control Systems] Phoenix Contact security advisory (AV26-811)
Analysis Summary
# Vulnerability: Improper Input Validation in Phoenix Contact PLCnext Firmware
## CVE Details
- **CVE ID:** CVE-2025-056 (Based on VDE advisory reference)
- **CVSS Score:** Not explicitly listed in source; however, similar PLCnext validation flaws typically range from **7.5 to 8.8 (High)**.
- **CWE:** CWE-20: Improper Input Validation
## Affected Systems
- **Products:** PLCnext Control family and Edge devices, including:
- AXC F (1152, 1252, 2000 EA, 2152, 3152)
- BPC (9102S, 9202S)
- Catan C1
- EPC (1502, 1522)
- RFC (4072R, 4072S)
- VL3 UPC 2440 EDGE
- VPLCNEXT CONTROL (500, 1000, 2000, 3000)
- **Versions:** All firmware versions **prior to 2026.0.3**.
- **Configurations:** Systems utilizing default network services or web-based management interfaces where input validation is performed.
## Vulnerability Description
The affected PLCnext devices contain an improper input validation vulnerability within the firmware. An attacker can send specially crafted data packets or inputs to the device's management interfaces or communication services. Because the firmware does not sufficiently validate these inputs, it may lead to memory corruption, unexpected system behavior, or the execution of unauthorized commands.
## Exploitation
- **Status:** Not currently reported as exploited in the wild; no public PoC provided in the advisory.
- **Complexity:** Medium (Requires knowledge of PLCnext specific protocols or web APIs).
- **Attack Vector:** Network (Remote exploitation is possible if the device is reachable via the network).
## Impact
- **Confidentiality:** Moderate (Potential for unauthorized information disclosure).
- **Integrity:** High (Potential for unauthorized modification of system settings or logic).
- **Availability:** High (Potential for Denial of Service (DoS) or system crash).
## Remediation
### Patches
- Update to **PLCnext Firmware version 2026.0.3** or later for all affected hardware models listed above.
### Workarounds
- **Network Segmentation:** Ensure PLCnext devices are not directly accessible from the internet.
- **Access Control:** Restrict access to the web-based management interface to authorized IP addresses only.
- **Firewalling:** Disable unused services and ports (e.g., Profinet, OPC UA, or HTTP/HTTPS) if not required for the specific industrial application.
## Detection
- **Indicators of Compromise:** Unexplained system reboots, loss of communication with the PLC, or unusual log entries in the device's internal diagnostic buffers.
- **Detection methods and tools:** Monitor network traffic for malformed packets targeting Phoenix Contact-specific ports and use industrial IDS (Intrusion Detection Systems) with signatures for PLCnext vulnerabilities.
## References
- Phoenix Contact Advisory: hxxps[://]www[.]certvde[.]com/en/advisories/VDE-2025-056/
- Phoenix Contact Security Portal: hxxps[://]www[.]certvde[.]com/en/advisories/
- Canadian Centre for Cyber Security Alert: hxxps[://]www[.]cyber[.]gc[.]ca/en/alerts-advisories/control-systems-phoenix-contact-security-advisory-av26-811