Siemens OZW672 and OZW772 XSS Vulnerability
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Independent researcher Aditya Sood has identified a cross-site scripting vulnerability in Siemens OZW672 and OZW772 devices. Siemens has produced a firmware update to mitigate this vulnerability.
This vulnerability could be exploited remotely.
Siemens reports that the vulnerability affects the following products:
- OZW672: All versions prior to V6.00
- OZW772: All versions prior to V6.00
An attacker who exploits this vulnerability may be able to change data and settings on the target device.
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.
Siemens is an international company headquartered in Munich, Germany.
OZW devices are web servers used for remote monitoring of building controller devices, such as heating or air conditioning. According to Siemens, these devices are deployed across several sectors, including Commercial Facilities. Siemens estimates that these products are used worldwide.
The web server login form input is not sanitized correctly, which results in a cross-site scripting vulnerability.
This vulnerability could be exploited remotely.
EXISTENCE OF EXPLOIT
No known public exploits specifically target this vulnerability.
An attacker with a medium skill would be able to exploit this vulnerability.
Siemens has created firmware updates to fix the vulnerability. Siemens recommends customers upgrade to the new firmware versions. As a general security measure, Siemens strongly recommends to protect network access to OZW products with appropriate mechanisms. It is advised to follow recommended security practices in order to run the devices in a protected IT environment.
Firmware updates for OZW672 products can be obtained at:
Firmware updates for OZW772 products can be obtained at:
For more information on this vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-743465 at the following location:
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 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.
- a. CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), http://cwe.mitre.org/data/definitions/79.html, web site last accessed January 19, 2016.
- b. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-1488, web site last accessed January 19, 2016.
- c. CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S..., web site last accessed January 19, 2016.
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