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Siemens SIMATIC WinCC Vulnerabilities

Act NowICS-CERT ICSA-12-030-01ANov 2, 2012
Summary

Siemens SIMATIC WinCC contains multiple vulnerabilities affecting authentication, input validation, and command execution. Affected versions include WinCC flexible (2004–2008), WinCC V11 (all versions), WinCC Runtime Advanced, and all SIMATIC HMI panel types (TP, OP, MP, Comfort, Mobile). Vulnerabilities include authentication bypass (CWE-287, CWE-306), improper input validation (CWE-20, CWE-119), cross-site scripting (CWE-79), code injection (CWE-94), and unsafe variable substitution (CWE-134). An attacker with network access could bypass authentication, inject malicious code into the HMI interface, or craft commands that alter process control logic and operator inputs sent to downstream equipment.

What this means
What could happen
An attacker with access to a WinCC workstation or HMI panel could inject malicious commands into the operator interface, potentially altering process parameters, hijacking control logic, or disrupting plant operations. Multiple vulnerabilities span authentication bypass, code injection, and unsafe command handling.
Who's at risk
Manufacturing facilities and utilities using Siemens WinCC as their human-machine interface and engineering platform should be concerned. This includes operators and engineers managing SIMATIC PLCs, TP/OP/MP/Comfort Panels (physical HMI touchscreens), and any facility relying on WinCC for process monitoring and control. All versions of WinCC flexible (2004–2008), WinCC V11, and associated HMI panels are affected.
How it could be exploited
An attacker with network access to a WinCC engineering workstation or HMI panel could craft malicious input (via web interface, project files, or direct network commands) to bypass authentication checks, inject code into the HMI application, or execute arbitrary commands on the system running WinCC. Depending on the vulnerability chain, this could allow modification of automation logic or operator commands sent to downstream PLCs and equipment.
Prerequisites
  • Network access to WinCC workstation or HMI panel (port 80/443 for web interface, Modbus TCP port 502, or Siemens-specific protocols)
  • No valid credentials required for some authentication bypass paths (CWE-287, CWE-306)
  • Ability to upload or inject malicious project files or craft network packets with specially formatted input
  • WinCC must be running and accessible from attacker's network segment
No patch available for any affected productMultiple code injection and authentication bypass pathways (CWE-79, CWE-94, CWE-287, CWE-306)Affects safety-critical systems (HMI panels control live manufacturing/utility processes)Remotely exploitable via network protocols and web interfacesLow complexity exploitation for some attack paths
Exploitability
High exploit probability (EPSS 34.6%)
Affected products (5)
2 pending3 EOL
ProductAffected VersionsFix Status
WinCC flexible: 2004|2005|2007|20082004|2005|2007|2008No fix yet
Multiple SIMATIC HMI panels (TP, OP, MP, Comfort Panels, Mobile Panels): vers:all/*All versionsNo fix yet
WinCC V11 (TIA portal): vers:all/*All versionsNo fix (EOL)
WinCC V11 Runtime Advanced: vers:all/*All versionsNo fix (EOL)
WinCC flexible Runtime: vers:all/*All versionsNo fix (EOL)
Remediation & Mitigation
0/6
Do now
0/3
HARDENINGIsolate WinCC workstations and HMI panels on a separate network segment or VLAN; restrict network access to engineering workstations and authorized operator terminals only
HARDENINGImplement firewall rules to block unauthorized access to WinCC ports (typically 80, 443, 502, and Siemens proprietary ports); restrict communication to known engineering and SCADA server IPs
WORKAROUNDDisable or restrict web-based access to HMI panels and WinCC runtime systems if not required for operations; use VPN or jump host for remote engineering access
Schedule — requires maintenance window
0/3

Patching may require device reboot — plan for process interruption

HARDENINGMonitor WinCC workstations and HMI panels for unauthorized project changes, suspicious file uploads, or unexpected network connections
HARDENINGApply principle of least privilege: limit operator accounts to read-only access where possible; use separate service accounts for automation tasks
HARDENINGAudit and validate all WinCC project files before deployment; scan for suspicious scripts or embedded commands in project archives
View full CISA ICS-CERT advisory
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Siemens SIMATIC WinCC Vulnerabilities - OTPulse