U.S. Flag Official website of the Department of Homeland Security
U.S. Department of Homeland Security Seal. ICS-CERT. Industrial Control Systems Cyber Emergency Response Team.
TLP:WHITE

Advisory (ICSA-16-327-02A)

Siemens SIMATIC CP 343-1/CP 443-1 Modules and SIMATIC S7-300/S7-400 CPUs Vulnerabilities (Update A)

Original release date: November 22, 2016 | Last revised: March 21, 2017

Legal Notice

All information products included in http://ics-cert.us-cert.gov are provided "as is" for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained within. DHS does not endorse any commercial product or service, referenced in this product or otherwise. Further dissemination of this product is governed by the Traffic Light Protocol (TLP) marking in the header. For more information about TLP, see http://www.us-cert.gov/tlp/.



OVERVIEW

This updated advisory is a follow-up to the original advisory titled ICSA-16-327-02 Siemens SIMATIC CP 343-1CP 443-1 Modules and SIMATIC S7-300S7-400 CPUs Vulnerabilities that was published November 22, 2016, on the NCCIC/ICS-CERT web site.

Siemens has released an advisory regarding vulnerabilities affecting SIMATIC CP 343-1 Advanced/CP-443-1 Advanced devices and SIMATIC S7-300/S7-400 CPUs. Inverse Path auditors and the Airbus ICT Industrial Security team reported these vulnerabilities directly to Siemens. Siemens has made new firmware versions available for several products and a temporary fix for the remaining affected products to mitigate these vulnerabilities.

These vulnerabilities could be exploited remotely.

AFFECTED PRODUCTS

--------- Begin Update A Part 1 of 2 --------

Siemens reports that the vulnerabilities affect the following SIMATIC products:

  • SIMATIC CP 343-1 Advanced: All versions prior to V3.0.53,
  • SIMATIC CP 443-1 Advanced: All versions prior to V3.2.17,
  • SIMATIC S7-300 CPU family: All firmware versions, and
  • SIMATIC S7-400 CPU family: All firmware versions.

--------- End Update A Part 1 of 2 ----------

IMPACT

Under certain conditions, an attacker could use these vulnerabilities to perform operations as an authenticated user.

Impact to individual organizations depends on many factors that are unique to each organization. ICS-CERT recommends that organizations evaluate the impact of these vulnerabilities based on their operational environment, architecture, and product implementation.

BACKGROUND

Siemens is a multinational company headquartered in Munich, Germany.

Communication Processor (CP) modules SIMATIC CP 343-1 Advanced and CP 443-1 Advanced are designed to enable SIMATIC S7-300/S7-400 CPUs to communicate via Ethernet.

According to Siemens, several critical infrastructure (CI) sectors deploy these products, including Chemical, Critical Manufacturing, and Food and Agriculture. Siemens estimates that users of these products are located worldwide.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

INSUFFICIENT VERIFICATION OF DATA AUTHENTICITYa

The integrated web server at Port 80/TCP or Port 443/TCP of the affected devices could allow remote attackers to perform actions with the permissions of an authenticated user, provided the targeted user has an active session and is induced to trigger the malicious request.

CVE-2016-8673b has been assigned to this vulnerability. A CVSS v3 base score of 6.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L).c

SENSITIVE COOKIE IN HTTPS SESSION WITHOUT 'SECURE' ATTRIBUTEd

The integrated web server delivers cookies without the “secure” flag. Modern browsers interpreting the flag would mitigate potential data leakage in case of clear text transmission.

CVE-2016-8672e has been assigned to this vulnerability. A CVSS v3 base score of 4.0 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N).f

VULNERABILITY DETAILS

EXPLOITABILITY

These vulnerabilities could be exploited remotely.

EXISTENCE OF EXPLOIT

No known public exploits specifically target these vulnerabilities.

DIFFICULTY

An attacker with a low skill may be able to exploit these vulnerabilities.

MITIGATION

Siemens provides firmware versions that fix the vulnerabilities and recommends that users update to the fixed versions:

  • SIMATIC CP 343-1 Advanced: Update to V3.0.53:

https://support.industry.siemens.com/cs/ww/en/view/109742236

--------- Begin Update A Part 2 of 2 --------

  • SIMATIC CP 443-1 Advanced: Update to V3.2.17:

https://support.industry.siemens.com/cs/ww/en/view/109745388

--------- End Update A Part 2 of 2 --------

For SIMATIC S7-300/S7-400 CPUs, Siemens recommends the following mitigations:

  • Apply cell protection concept,
  • Use VPN for protecting network communication between cells, and
  • Apply Defense-in-Depth.

Siemens strongly recommends users protect network access to SIMATIC S7-300/S7-400 CPUs and to the web interface of SIMATIC CP 343-1 Advanced and CP 443-1 Advanced devices with appropriate mechanisms. Siemens also advises that users configure the protected operational environment according to Siemens’ Operational Guidelines for Industrial Security:

https://www.siemens.com/cert/operational-guidelines-industrial-security

For more information on this vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-603476 at the following location:

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

Siemens will update SSA-603476 and ICS-CERT will update this advisory when new information becomes available.

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 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.

ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

ICS-CERT 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 in the ICS‑CERT Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies, that is available for download from the ICS-CERT web site.

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


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?

The NCCIC continuously strives to improve its products and services. You can help by choosing one of the links below to provide feedback about this product.

Was this document helpful?  Yes  |  Somewhat  |  No

Back to Top