FATEK Automation PLC WinProladder Stack-Based Buffer Overflow Vulnerability
Plan Patch8ICS-CERT ICSA-16-350-01Sep 18, 2016
Attack VectorNetwork
Auth RequiredLow
ComplexityLow
User InteractionRequired
Summary
FATEK Automation PLC WinProladder contains a stack-based buffer overflow vulnerability in ladder program processing. An attacker with engineering credentials can craft a malicious ladder program that, when uploaded to the PLC, triggers a stack buffer overflow, potentially allowing arbitrary code execution on the controller. This affects WinProladder version 3.11_Build_14701 and no vendor patch is currently available.
What this means
What could happen
An attacker with valid engineering credentials could upload a malicious ladder program to the PLC, executing arbitrary commands that alter process logic, disable safety interlocks, or halt production.
Who's at risk
Manufacturing facilities using FATEK Automation PLC with WinProladder for control logic programming, including discrete manufacturing, process control, and packaging operations. This vulnerability affects systems where engineering staff have access to load or modify ladder programs.
How it could be exploited
An attacker with engineering workstation credentials connects to WinProladder, crafts a malicious ladder program with a stack overflow payload, and uploads it to the PLC. The overflow corrupts memory on the controller, allowing arbitrary code execution during program execution.
Prerequisites
- Valid engineering workstation credentials (username/password)
- Network access to WinProladder engineering interface (port 502 or engineering workstation communication channel)
- Physical access to engineering workstation or compromise of engineering credentials
- PLC must be in a state to accept ladder program uploads
Low complexity exploitationRequires valid credentials (engineering access)No patch availableAffects control logic execution8.6% exploit probability (moderate EPSS)
Exploitability
Moderate exploit probability (EPSS 8.6%)
Affected products (1)
ProductAffected VersionsFix Status
PLC WinProladder: 3.11_Build_147013.11 Build 14701No fix (EOL)
Remediation & Mitigation
0/5
Do now
0/2HARDENINGRestrict network access to the engineering workstation and PLC to authorized personnel only; implement firewall rules limiting WinProladder communications to known engineering subnets.
HARDENINGEnforce strong, unique passwords for all engineering workstation accounts; implement multi-factor authentication if available.
Schedule — requires maintenance window
0/2Patching may require device reboot — plan for process interruption
HARDENINGMonitor ladder program uploads and PLC configuration changes; log all engineering access for audit trails.
WORKAROUNDRegularly review and validate the integrity of deployed ladder programs on all affected PLCs.
Mitigations - no patch available
0/1PLC WinProladder: 3.11_Build_14701 has reached End of Life. The vendor will not release a patch. Apply the following compensating controls:
HARDENINGSegregate the engineering network from general IT and production networks using air gaps or unidirectional security gateways where possible.
CVEs (1)
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