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-16-271-01)

Siemens SCALANCE M-800/S615 Web Vulnerability

Original release date: September 27, 2016 | Last revised: August 22, 2018

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

Siemens has identified a web security vulnerability in Siemen’s SCALANCE M-800 and S615 modules. This vulnerability was reported directly to Siemens by Alexander Van Maele and Tijl Deneut from HOWEST. Siemens has produced a new firmware version to mitigate this vulnerability.

AFFECTED PRODUCTS

Siemens reports that the vulnerability affects the following products:

  • SCALANCE M-800/S615: All versions before V4.02

IMPACT

Exploitation of this vulnerability could allow an attacker in a privileged network position to obtain web session cookies under certain circumstances.

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

BACKGROUND

Siemens is a multinational company headquartered in Munich, Germany.

The affected products are SCALANCE M-800/S615 modules. SCALANCE M industrial routers are industrial-grade routers used to connect networked industrial components. This product line provides a Web interface to manage the router configuration. The SCALANCE S firewall is used to protect trusted industrial networks from untrusted networks and provides additional security functionality, e.g., VPN tunnels==2E. According to Siemens, SCALANCE M-800/S615 modules are deployed across several sectors including Chemical, Critical Manufacturing, Dams, Defense Industrial Base, Energy, Food and Agriculture, Government Facilities, Transportation Systems, and Water and Wastewater Systems. Siemens estimates that these products are used worldwide.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

SENSITIVE COOKIE IN HTTPS SESSION WITHOUT "SECURE" ATTRIBUTEa

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

CVE-2016-7090b has been assigned to this vulnerability. A CVSS v3 base score of 4.0 has been calculated; the CVSS vector string is (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N).c

VULNERABILITY DETAILS

EXPLOITABILITY

This vulnerability could be exploited remotely.

EXISTENCE OF EXPLOIT

No known public exploits specifically target this vulnerability.

DIFFICULTY

Crafting a working exploit for this vulnerability would be difficult.

MITIGATION

Siemens provides firmware version V4.2 for SCALANCE M-800/S615 to mitigate this vulnerability. The firmware version can be obtained here:

https://support.industry.siemens.com/cs/ww/en/view/109740858

Siemens strongly recommends users protect network access to the management interface of SCALANCE M-800/S615 modules with appropriate mechanisms. Siemens also advises that users configure the operational environment according to Siemens overview of the operational guidelines for Industrial Security (with the cell protection concept):

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-342135 at the following location:

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

ICS-CERT recommends that 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.

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 at: http://ics-cert.us-cert.gov/content/recommended-practices. 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 (http://ics-cert.us-cert.gov/).

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