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Phoenix Contact: PLCnext Control prone to download of code without integrity check

Monitor7.7VDE-2023-058Dec 12, 2023
Attack VectorNetwork
Auth RequiredLow
ComplexityLow
User InteractionNone needed
Summary

PLCnext Control application files (logic, executables, configurations) lack robust integrity verification. An authenticated attacker could craft malicious application files in a way that bypasses the integrity check mechanism, allowing unauthorized modifications to be loaded onto the PLC undetected. PLCnext Engineer should warn users of integrity mismatches when in Online mode, but a skilled attacker could potentially craft changes that evade this detection. The vulnerability affects all current PLCnext Control hardware platforms through version 2024.0, and the vendor has not released patches.

What this means
What could happen
An authenticated attacker could manipulate PLC application files (logic, configurations) in a way that bypasses integrity checks, allowing unauthorized changes to industrial processes that are difficult to detect or remove. This could lead to undetected tampering with control logic, process parameters, or safety interlocks.
Who's at risk
Manufacturing facilities using Phoenix Contact PLCnext Control systems (AXC F series controllers, BPC 9102S gateway, EPC 1502/1522 edge controllers, RFC 4072R/S safety controllers, and PLCnext Engineer software) are affected. This impacts any organization that uses these PLCs to control automated processes, assembly lines, or safety-critical equipment.
How it could be exploited
An attacker with valid credentials and access to the PLCnext Engineer workstation or network connection to the PLC could craft malicious application files that evade the integrity verification mechanisms. The attacker would then upload or transfer these tampered files to the PLC, where the weakened integrity check fails to detect the manipulation, and the malicious code executes as part of the normal application.
Prerequisites
  • Valid engineering workstation credentials (PLCnext Engineer user account)
  • Network access to the PLC (direct engineering connection or remote access)
  • Knowledge of PLCnext application file structure and integrity check mechanisms
  • Access to PLC application files during engineering phase or through compromised engineering workstation
Remotely exploitable (with credentials and network access)Authentication required (but uses credentials, not multi-factor)No patch available for affected versionsCould affect safety system configurationsIntegrity check bypass reduces detectability of tampering
Affected products (9)
9 EOL
ProductAffected VersionsFix Status
AXC F 2152≤ 2024.0No fix (EOL)
AXC F 3152≤ 2024.0No fix (EOL)
BPC 9102S≤ 2024.0No fix (EOL)
EPC 1522≤ 2024.0No fix (EOL)
RFC 4072R≤ 2024.0No fix (EOL)
RFC 4072S≤ 2024.0No fix (EOL)
PLCnext Engineer <=2024.0≤ 2024.0No fix (EOL)
AXC F 1152≤ 2024.0No fix (EOL)
Remediation & Mitigation
0/8
Do now
0/5
HARDENINGRestrict PLCnext Engineer workstation access to authorized engineering personnel only; disable local admin accounts and enforce strong password policies
HARDENINGIsolate engineering networks (PLCnext Engineer to PLC communication) on a separate VLAN or air-gapped network segment not connected to production control network
WORKAROUNDRequire VPN for any remote access to PLCnext Engineer workstations or PLC systems; restrict non-VPN access at the firewall
HARDENINGEnable and verify PLCnext Control project data integrity check feature is active; review the integrity check settings and logging configuration
HARDENINGDo not transfer PLC project files via email or unencrypted file sharing; establish a secure, authenticated file transfer process with integrity verification (e.g., signed files, checksums)
Schedule — requires maintenance window
0/3

Patching may require device reboot — plan for process interruption

HARDENINGMonitor PLCnext Engineer and PLC logs for 'Project Integrity Warning' entries; investigate and document any integrity warnings and remediate deviations from the known-good project
HARDENINGImplement certificate-based authentication for PLC access; use certificate management features in PLCnext Control to control which engineering workstations can connect
HOTFIXCheck Phoenix Contact PSIRT and product download pages regularly for firmware updates; apply latest Long-Term Support (LTS) versions when available and tested in your environment
View full CERT@VDE advisory
API: /api/v1/advisories/361e2066-b93d-42c3-adbc-f758bf8197c1