GE D20ME PLC Vulnerabilities (Update A)

ICS-CERT is aware of a public report of vulnerabilities with proof-of-concept (PoC) exploit code affecting the General Electric (GE) D20ME, part of the GE D20Substation Controller product.

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Summary

ICS-CERT is aware of a public report of vulnerabilities with proof-of-concept (PoC) exploit code affecting the General Electric (GE) D20ME, part of the GE D20Substation Controller product. According to this report, the vulnerabilities are exploitable by using TFTP connections to the controller. This report is based on information presented by Reid Wightman during Digital Bond’s SCADA Security Scientific Symposium (S4) on January19, 2012, without coordination with either the vendor or ICS-CERT.

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Reid Wightman, of Digital Bond, has released Metasploit modules to exploit the vulnerabilities outlined in this alert.

Newly Released Metasploit module

• d20_tftp_overflow: : triggers a Denial of Service condition due to a buffer overflow vulnerability in GE's D20ME PLC TFTP server.

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ICS-CERT has notified GE of the report and has asked GE to confirm the vulnerabilities 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 included vulnerability details and PoC exploit code for the following vulnerabilities:

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

Mitigation

ICS-CERT is currently coordinating with GE and the security researcher to identify mitigations.

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GE requests that users contact their GE support representative for additional mitigation information for these vulnerabilities.

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

• Minimize network exposure for all control system devices. Control system devices should not directly face the Internet.a
• 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.

• a. ICS-CERT ALERT, http://www.us-cert.gov/control_systems/pdf/ICS-Alert-10-301-01.pdf, website last accessed April 09, 2012.