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TLP:WHITE

Advisory (ICSA-17-243-02)

Siemens LOGO!

Original release date: August 31, 2017

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CVSS v3 7.5

ATTENTION: Remotely exploitable/low skill level to exploit.

Vendor: Siemens

Equipment: LOGO!

Vulnerabilities: Insufficiently Protected Credentials, Man-in-the-Middle

AFFECTED PRODUCTS

Siemens reports that the vulnerabilities affect the following LOGO! devices:

  • LOGO!8 BM: All versions.

IMPACT

Successful exploitation of these vulnerabilities could allow an attacker to hijack existing web sessions.

MITIGATION

Siemens provides LOGO!8 BM FS-05 with firmware Version V1.81.2, which fixes the first vulnerability.

Siemens recommends applying the following mitigations for users with existing installations, and for mitigation of the second vulnerability:

  • Configure the environment according to the recommendations in the user manual:

https://support.industry.siemens.com/cs/us/en/view/109741041

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

https://www.industry.siemens.com/topics/global/en/industrial-security/Pages/default.aspx

As a general security measure, Siemens strongly recommends protecting network access to the devices with appropriate mechanisms. Siemens advises configuring the environment according to Siemens operational guidelines in order to run the devices in a protected IT environment.

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

For more information on these vulnerabilities and more detailed mitigation instructions, please see Siemens Security Advisory SSA-087240 at the following location:

http://www.siemens.com/cert/en/cert-security-advisories.htm

NCCIC/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.

No known public exploits specifically target these vulnerabilities.

VULNERABILITY OVERVIEW

An attacker with network access to the integrated web server on Port 80/TCP could obtain the session ID of an active user session. A user must be logged in to the web interface. Siemens recommends that users use the integrated webserver on Port 80/TCP only in trusted networks.

CVE-2017-12734 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

An attacker who performs a Man-in-the-Middle attack between the LOGO! and other devices could potentially decrypt and modify network traffic.

CVE-2017-12735 has been assigned to this vulnerability. A CVSS v3 base score of 7.4 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N).

RESEARCHER

Maxim Rupp discovered one of these two vulnerabilities.

BACKGROUND

Critical Infrastructure Sectors: Commercial Facilities, Transportation Systems

Countries/Areas Deployed: Worldwide

Company Headquarters Location: Germany


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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