ICS Advisory (ICSA-19-134-02)

Siemens SIMATIC WinCC and SIMATIC PCS 7

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1. EXECUTIVE SUMMARY

  • CVSS v3 9.8
  • ATTENTION: Exploitable remotely/low skill level to exploit
  • Vendor: Siemens
  • Equipment: SIMATIC WinCC and SIMATIC PCS 7
  • Vulnerability: Missing Authentication for Critical Function

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an unauthenticated attacker with access to the affected devices to execute arbitrary code.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Siemens reports that the vulnerability affects the following SIMATIC products:

  • SIMATIC PCS 7 v8.0 and earlier
  • SIMATIC PCS 7 v8.1 and newer (if "Encrypted Communication" is disabled)
  • SIMATIC WinCC v7.2 and earlier
  • SIMATIC WinCC v7.3 and newer (if "Encrypted Communication" is disabled)

3.2 VULNERABILITY OVERVIEW

3.2.1    MISSING AUTHENTICATION FOR CRITICAL FUNCTION CWE-306

If affected installations do not have “Encrypted Communication” configured, an unauthenticated attacker with network access may be able to execute arbitrary code.

CVE-2019-10922 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.3 BACKGROUND

  • CRITICAL INFRASTRUCTURE SECTORS: Chemical, Energy, Food and Agriculture, Water and Wastewater Systems
  • COUNTRIES/AREAS DEPLOYED: Worldwide
  • COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Vladimir Dashchenko and Sergey Temnikov from Kaspersky Lab reported this vulnerability to Siemens.

4. MITIGATIONS

Siemens recommends the following mitigations:

  • Upgrade SIMATIC WinCC to v7.3 or newer.
  • Upgrade SIMATIC PCS 7 to v8.1 or newer.
  • Enable “Encrypted Communications” (some newer versions have this enabled by default).
  • Apply defense-in-depth concepts.

As a general security measure, Siemens strongly recommends protecting network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends users configure their environment according to Siemens’ operational guidelines for industrial security and follow the recommendations in the product manuals.

Additional information on Industrial Security by Siemens can be found at:

https://www.siemens.com/industrialsecurity

For more information on the vulnerability and more detailed mitigation instructions, please see Siemens security advisory SSA-705517 at the following location:

http://www.siemens.com/cert/advisories

NCCIC recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

  • Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
  • Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
  • When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the connected devices.

NCCIC reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

NCCIC also provides a section for control systems security recommended practices on the ICS-CERT web page. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available on the ICS-CERT website in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to NCCIC for tracking and correlation against other incidents.

No known public exploits specifically target this vulnerability.


Contact Information

For any questions related to this report, please contact the NCCIC at:

Email: NCCICCUSTOMERSERVICE@hq.dhs.gov
Toll Free: 1-888-282-0870

For industrial control systems cybersecurity information:  http://ics-cert.us-cert.gov 
or incident reporting:  https://ics-cert.us-cert.gov/Report-Incident?

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