Siemens SIMATIC WinCC Flexible

This November 2011 alert describes multiple vulnerabilities with proof-of-concept (PoC) exploit code affecting Siemens SIMATIC WinCC Flexible Runtime, a human-machine interface product.

Summary

ICS-CERT is aware of a public report of multiple vulnerabilities with proof-of-concept (PoC) exploit code affecting Siemens SIMATIC WinCC Flexible Runtime, a human-machine interface product. According to this report, the vulnerabilities are exploitable remotely via Port 2308/TCP. This report was released by Luigi Auriemma without coordination with ICS-CERT, the vendor, or other coordination entity that ICS-CERT is aware of.

ICS-CERT has coordinated the report with Siemens, who is working to confirm the report and identify mitigations. ICS-CERT is issuing this alert to provide early notice of the report and identify baseline mitigations for reducing risks to these and other cybersecurity attacks.

The report includes details and PoC exploit code for the following vulnerabilities:

ICS-CERT and Siemens are currently evaluating the reported stack overflow vulnerability, which may be the same as a previously reported vulnerability.http://www.uscert.gov/control_systems/pdf/ICSA-11-244-01.pdf , website last accessed November 28, 2011.

Please report any issues affecting control systems in critical infrastructure environments to ICS-CERT.

Mitigation

ICS-CERT is currently coordinating with the vendor to identify mitigations.

ICS-CERT recommends that users take defensive measures to minimize the risk of exploitation of these vulnerabilities. Specifically, users should:

• Configure firewall rules appropriately for traffic on Port 2308/TCP.
• Minimize network exposure for all control system devices. Control system devices should not directly face the Internet.ICS-CERT ALERT, http://www.us-cert.gov/control_systems/pdf/ICS-Alert-10-301-01.pdf, website last accessed November 28, 2011.
• Locate control system networks and devices behind firewalls, and isolate them from the business network.
• If remote access is required, employ secure methods such as Virtual Private Networks (VPNs), recognizing that VPN is only as secure as the connected devices.

ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to taking defensive measures.
The Control Systems Security Program (CSSP) also provides a recommended practices section for control systems on the US-CERT website. Several recommended practices are available for reading or download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Organizations that observe any suspected malicious activity should follow their established internal procedures and report their findings to ICS-CERT for tracking and correlation against other incidents.

• Siemens