ATTENTION: Remotely exploitable/low skill level to exploit.
Equipment: OZW672 and OZW772
Vulnerabilities: Missing Authentication
Siemens reports that the vulnerability affects the following OZW672 and OZW772 devices for monitoring building controller devices:
Successful exploitation of this vulnerability could allow attackers to read and write historical measurement data under certain conditions, or to read and modify data in TLS sessions.
Siemens recommends applying the following mitigations:
For more information on this vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-563539 at the following location:
NCCIC/ICS-CERT recommends that users take defensive measures to minimize the risk of exploitation of these vulnerabilities. Specifically, users should:
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.
An attacker with access to Port 21/TCP could access or alter historical measurement data stored on the device.
A vulnerability in the integrated web server on Port 443/TCP could allow an attacker to read and manipulate data in TLS sessions while performing a man-in-the-middle (MITM) attack.
Stefan Viehböck from SEC Consult reported these vulnerabilities to Siemens.
Critical Infrastructure Sector: Commercial Facilities
Countries/Areas Deployed: Worldwide
Company Headquarters Location: Germany
For any questions related to this report, please contact the CISA at:
Toll Free: 1-888-282-0870
For industrial control systems cybersecurity information: https://www.us-cert.gov/ics
or incident reporting: https://www.us-cert.gov/report
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