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TLP:WHITE

Advisory (ICSA-17-353-04)

Siemens LOGO! Soft Comfort

Original release date: December 19, 2017

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CVSS v3 5.9

ATTENTION: Remotely exploitable.

Vendor: Siemens

Equipment: LOGO! Soft Comfort

Vulnerability: Download of Code without Integrity Check

AFFECTED PRODUCTS

Siemens reports that the vulnerability affects the following LOGO! Soft Comfort engineering software products:

  • LOGO! Soft Comfort: All versions prior to V8.2

IMPACT

Successful exploitation of this vulnerability could allow a remote attacker in a privileged network position to manipulate a software package during download.

MITIGATION

Siemens removed the Update Center from LOGO! Soft Comfort V8.2 and provides SHA-256 checksums for all LOGO! Soft Comfort software packages via a secured HTTPS channel. Siemens recommends verifying legitimacy by comparing the SHA-256 checksum of the downloaded software package with the SHA-256 checksum provided for the software package.  Software version 8.2 for LOGO! Soft Comfort and SHA-256 checksums for LOGO! Soft Comfort downloads can be obtained via:

https://www.siemens.com/logo-update

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 this vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-888929 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 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. 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.

In addition, ICS-CERT recommends that users take the following measures to protect themselves from social engineering attacks:

  1. Do not click web links or open unsolicited attachments in email messages.
  2. Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.
  3. Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks.

No known public exploits specifically target this vulnerability. High skill level is needed to exploit.

VULNERABILITY OVERVIEW

The update center of LOGO! Soft Comfort lacks integrity verification on software packages downloaded via an unprotected communication channel. This could allow a remote attacker to manipulate the software package while performing a man-in-the-middle (MitM) attack.

CVE-2017-12740 has been assigned to this vulnerability. A CVSS v3 base score of 5.9 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N).

RESEARCHER

Tobias Gebhardt reported this vulnerability to Siemens.

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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