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WAGO: Multiple Vulnerabilities in CODESYS Runtime 2.3 and WebVisualisation

Act Now9.1VDE-2021-056Nov 16, 2021
Attack VectorNetwork
Auth RequiredNone
ComplexityLow
User InteractionNone needed
Summary

Multiple vulnerabilities in CODESYS 2.3 Runtime and WebVisualisation affect WAGO PLC controllers. The vulnerabilities include buffer overflows (CWE-126, CWE-823, CWE-122), improper error handling (CWE-252), and null pointer dereference (CWE-476), which could lead to denial of service or information disclosure. All WAGO 750-series Ethernet controllers and PFC200 controllers running CODESYS 2.3 Runtime with firmware versions listed in the affected products table are vulnerable. Vendors have released fixed firmware versions for all affected models.

What this means
What could happen
Multiple memory corruption and access vulnerabilities in CODESYS 2.3 Runtime could allow an attacker to crash your PLC or potentially execute arbitrary code, disrupting production processes and equipment control.
Who's at risk
Manufacturing facilities using WAGO PLC controllers (750-series Ethernet or PFC200 series) running CODESYS 2.3 Runtime are affected. This includes plants relying on these PLCs for process automation, motion control, or equipment safety logic.
How it could be exploited
An attacker with network access to the PLC could send specially crafted requests to the CODESYS 2.3 Runtime (default port 2455) or WebVisualisation interface to trigger buffer overflows, out-of-bounds memory access, or null pointer dereference, leading to process termination or code execution.
Prerequisites
  • Network access to port 2455 (CODESYS Runtime) or WebVisualisation interface
  • No authentication required
remotely exploitableno authentication requiredlow complexityaffects industrial control systemshigh CVSS score (9.1)
Affected products (27)
27 with fix
ProductAffected VersionsFix Status
750-8202/xxx-xxx≤ 03.07.14 (19)FW20
750-8203/xxx-xxx≤ 03.07.14 (19)FW20
750-8204/xxx-xxx≤ 03.07.14 (19)FW20
750-8206/xxx-xxx≤ 03.07.14 (19)FW20
750-8207/xxx-xxx≤ 03.07.14 (19)FW20
Remediation & Mitigation
0/4
Do now
0/2
WORKAROUNDDisable CODESYS 2.3 WebVisualisation feature on all affected PLCs.
WORKAROUNDDisable or restrict access to CODESYS 2.3 port 2455 using firewall rules; block inbound traffic to this port from untrusted networks.
Schedule — requires maintenance window
0/1

Patching may require device reboot — plan for process interruption

750-823
HOTFIXUpdate PLC firmware to the fixed versions listed in the advisory: 750-823 to FW10 or later, 750-829/831/852/880/881/882/885/889 to FW17 or later, 750-832/862/890/891/893 to FW10 or later, and 750-8202/8203/8204/8206/8207/8208/8210/8211/8212/8213/8214/8216/8217 to FW20 or later.
Long-term hardening
0/1
HARDENINGRestrict network access to affected PLCs; do not allow direct connectivity from untrusted networks or the internet.
View full CERT@VDE advisory
API: /api/v1/advisories/3144ba79-581f-4519-9b6e-aca266144064