Siemens OZW Web Server

# ICS Advisory (ICSA-20-042-09) ## Siemens OZW Web Server Original release date: February 11, 2020 [Print Document](javascript:window.print\(\);) [Tweet](https://twitter.com/share?url=https%3A%2F%2Fus- cert.cisa.gov%2Fics%2Fadvisories%2Ficsa-20-042-09) [Like Me](https://www.facebook.com/sharer.php?u=https%3A%2F%2Fus- cert.cisa.gov%2Fics%2Fadvisories%2Ficsa-20-042-09) [Share](http://www.addthis.com/bookmark.php?url=https%3A%2F%2Fus- cert.cisa.gov%2Fics%2Fadvisories%2Ficsa-20-042-09) ### Legal Notice All information products included in [https://us-cert.gov/ics](/ics) 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 [https://www.us- cert.gov/tlp/](/tlp/). * * * ## 1\. EXECUTIVE SUMMARY * **CVSS v3 5.3** * **ATTENTION:** Exploitable remotely/low skill level to exploit * **Vendor:** Siemens * **Equipment:** OZW web server * **Vulnerability:** Information disclosure ## 2\. RISK EVALUATION Successful exploitation of this vulnerability could allow unauthenticated users to access project files. ## 3\. TECHNICAL DETAILS ### 3.1 AFFECTED PRODUCTS The following versions of OZW web server are affected: * OZW672 and OZW772: All versions prior to 10.0 ### 3.2 VULNERABILITY OVERVIEW #### 3.2.1 [INFORMATION DISCLOSURE CWE-552](https://cwe.mitre.org/data/definitions/552.html) Vulnerable versions of OZW web server use predictable path names for project files that legitimately authenticated users have created by using the application's export function. By accessing a specific uniform resource locator on the web server, a remote attacker could be able to download a project file without prior authentication. [CVE-2019-13941](http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2019-13941) has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been calculated; the CVSS vector string is ([AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N](https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)). ### 3.3 BACKGROUND * **CRITICAL INFRASTRUCTURE SECTORS** : Commercial Facilities, Government Facilities * **COUNTRIES/AREAS DEPLOYED:** Worldwide * **COMPANY HEADQUARTERS LOCATION:** Germany ### 3.4 RESEARCHER Maxim Rupp reported this vulnerability to Siemens. ## 4\. MITIGATIONS Siemens recommends users to update [OZW672](https://support.industry.siemens.com/cs/document/62567396) and [OZW772](https://support.industry.siemens.com/cs/document/62564534) to version 10.0 Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk: * Configure the product according to the [OZW hardening guidelines](https://support.industry.siemens.com/cs/document/67478477/ozw-security-advisory?lc=en-us). * Restrict access to the device to the internal or VPN network. Further, if possible, restrict access to the OZW Web Server to trusted IP addresses. As a general security measure Siemens strongly recommends users protect network access to affected products with appropriate mechanisms. It is advised to follow recommended security practices in order to run the devices in a protected IT environment. For more information refer to [SSA-986695](https://www.siemens.com/cert/advisories). CISA recommends 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](https://www.us-cert.gov/ics/alerts/ICS-ALERT-10-301-01). * 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. CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures. CISA also provides a section for [control systems security recommended practices](https://www.us-cert.gov/ics/recommended-practices) on the ICS webpage on [us-cert.gov](https://www.us-cert.gov/ics). Several recommended practices are available for reading and download, including [Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies](https://www.us- cert.gov/sites/default/files/recommended_practices/NCCIC_ICS- CERT_Defense_in_Depth_2016_S508C.pdf). Additional mitigation guidance and recommended practices are publicly available on the [ICS webpage on us-cert.gov](https://www.us-cert.gov/ics) in the Technical Information Paper, [ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies](https://www.us-cert.gov/ics/tips/ICS- TIP-12-146-01B). Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents. No known public exploits specifically target this vulnerability