01 June 2016
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2016.1374 Moxa UC 7408-LX-Plus Firmware Overwrite Vulnerability 1 June 2016 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Moxa UC 7408-LX-Plus Publisher: ICS-CERT Operating System: Network Appliance Impact/Access: Overwrite Arbitrary Files -- Existing Account Resolution: Mitigation CVE Names: CVE-2016-4500 Original Bulletin: https://ics-cert.us-cert.gov/advisories/ICSA-16-152-01 - --------------------------BEGIN INCLUDED TEXT-------------------- Advisory (ICSA-16-152-01) Moxa UC 7408-LX-Plus Firmware Overwrite Vulnerability Original release date: May 31, 2016 Legal Notice All information products included in http://ics-cert.us-cert.gov 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 http://www.us-cert.gov/tlp/. OVERVIEW NCCIC/ICS-CERT has received information from a third party that identified a firmware overwrite vulnerability in Moxas UC 7408-LX-Plus device. Moxa has produced instructions to reduce exposure to this vulnerability. The Moxa UC 7408-LX-Plus device has been discontinued. This vulnerability could be exploited remotely. AFFECTED PRODUCTS The following Moxa UC-7408 versions are affected: UC-7408 LX-Plus all versions. IMPACT A firmware overwrite has been used that is neither recoverable in the field or by the manufacturer, necessitating the replacement of the device. Impact to individual organizations depends on many factors that are unique to each organization. ICS-CERT recommends that organizations evaluate the impact of this vulnerability based on their operational environment, architecture, and product implementation. BACKGROUND Moxa is a Taiwan-based company that maintains offices in several countries around the world, including the US, UK, India, Germany, France, China, Russia, and Brazil. The affected product, UC-7408-LX-Plus, is an embedded computer. According to Moxa, these computers are deployed across several sectors, including Chemical, Commercial Facilities, Critical Manufacturing, Emergency Services, Energy, Food and Agriculture, Government Facilities, Water and Wastewater Systems, and others. Moxa estimates that this product is used globally but concentrated in the US, Europe, Chile, Argentina, Peru, Columbia, and Taiwan, with 50 to 60 percent of all sales in the US. VULNERABILITY CHARACTERIZATION VULNERABILITY OVERVIEW MISSING AUTHENTICATION FOR CRITICAL FUNCTION [a] The firmware overwrite is neither recoverable in the field or by the manufacturer, necessitating the replacement of the device. CVE-2016-4500 [b] has been assigned to this vulnerability. A CVSS v3 base score of 5.8 has been assigned; the CVSS vector string is (AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:N/A:H). [c] VULNERABILITY DETAILS EXPLOITABILITY This vulnerability could be exploited remotely. EXISTENCE OF EXPLOIT No known public exploits specifically target this vulnerability. DIFFICULTY Crafting a working exploit for this vulnerability would be difficult. Root level access is necessary for this exploit. This decreases the likelihood of a successful exploit. MITIGATION Moxa recommends the following suggestions to reduce the risk of unauthorized access to UC 7408-LX-Plus: Strengthen authentication requirements: - - Change passwords for administrative users periodically. - - Use the stronger password. Ex: mixed with upper and lower case character and number. - - Disable or delete unused profiles from system. - - Provide login authentication at all access portals before accessing this device ex: console, ssh, web. - - Disable unnecessary services. - - Enable system log for monitoring. - - Log unsuccessful login attempts. - - Auto log out from ssh or telnet console after a period of inactivity. Increase access control: - - Restrict mobile code download and execution. - - Limit the number of concurrent sessions. Ex: SSH is limited to 5. - - Log the access control information with timestamps for audit purpose. Enhance data integrity: - - Use secure transmission protocol, SSH, VPN, HTTPS, etc., to protect integrity of information. Enhance data confidentiality: - - Remove the shared data if the shared resource is not used. Restrict data flow: - - Enable firewall function for deny all accept exception rule. 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 ICSCERT 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-306: Missing Authentication for Critical Function, http://cwe.mitre.org/data/definitions/306.html, web site last accessed May 31, 2016. b. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-4500, NIST uses this advisory to create the CVE web site report. This web site will be active sometime after publication of this advisory. c. CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S..., web site last accessed May 31, 2016. Contact Information For any questions related to this report, please contact ICS-CERT at: Email: firstname.lastname@example.org (link sends e-mail) Toll Free: 1-877-776-7585 International Callers: (208) 526-0900 For industrial control systems security information and incident reporting: http://ics-cert.us-cert.gov ICS-CERT continuously strives to improve its products and services. You can help by choosing one of the links below to provide feedback about this product. - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to email@example.com and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: firstname.lastname@example.org Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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