26 October 2016
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2016.2495 Siemens SICAM RTU Devices Denial-of-Service Vulnerability 26 October 2016 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Siemens SICAM RTU Publisher: ICS-CERT Operating System: Network Appliance Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2016-7987 Original Bulletin: https://ics-cert.us-cert.gov/advisories/ICSA-16-299-01 - --------------------------BEGIN INCLUDED TEXT-------------------- Advisory (ICSA-16-299-01) Siemens SICAM RTU Devices Denial-of-Service Vulnerability Original release date: October 25, 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 Adam Crain of Automatak LLC has identified a denial-of-service vulnerability in Siemens SICAM products. Siemens has produced a firmware update to mitigate this vulnerability. This vulnerability could be exploited remotely. AFFECTED PRODUCTS Siemens reports that the vulnerability affects the following versions of SICAM: ETA4 firmware (all versions prior to Revision 08) of the SM-2558 extension module for: SICAM AK, SICAM TM 1703, SICAM BC 1703, and SICAM AK 3 ETA2 firmware (Revision 11.01 and earlier) of the SM-2556 extension module for: SICAM AK, SICAM TM, and SICAM BC. IMPACT Successful exploitation of this vulnerability could cause a denial of service. A cold start might be required to recover the system. 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. BACKGROUND Siemens is a multinational company headquartered in Munich, Germany. The affected products, SM-2558 and SM-2556, are communication modules used to connect networked industrial components. According to Siemens, SM-2558 and SM-2556 communication modules are deployed across several sectors including Chemical, Critical Manufacturing, Government Facilities, and others. Siemens estimates that these products are used worldwide. VULNERABILITY CHARACTERIZATION VULNERABILITY OVERVIEW DENIAL OF SERVICE[a] Specially crafted packets sent to Port 2404/TCP could cause the affected device to go into defect mode. A cold start might be required to recover the system. CVE-2016-7987[b] has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/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 An attacker with a low skill would be able to exploit this vulnerability. MITIGATION Siemens provides firmware ETA4 Revision 08 for SM-2558 that fixes the vulnerability and recommends customers update to the fixed version. http://w3.siemens.com/smartgrid/global/en/products-systems-solutions/substation-automation/substation-automation/Pages/Overview.aspx (link is external) For the SM-2556 extension module, Siemens recommends customers contact the support center at: firstname.lastname@example.org (link sends e-mail) Until patches can be applied, Siemens advises to apply the following steps to mitigate the risk: Use a firewall or the IPsec functionality of the SM-2558 module to restrict access to Port 2404/TCP The SICAM RTUs ADMINISTRATOR Security Manual: www.downloads.siemens.com/download-center/d/SIC_RTUs_ADMIN_SECURITY_ENG.pdf?mandator=ic_sg&segment=Global&fct=downloadasset&pos=download&id1=DLA05_43299 (link is external) Always run RTUs in trusted networks. As a general security measure Siemens strongly recommends to protect network access with appropriate mechanisms (e.g., firewalls, segmentation, VPN). It is advised to configure the environment according to Siemens operational guidelines in order to run the devices in a protected IT environment. Siemens recommends security guidelines to Secure Substation: http://www.siemens.com/gridsecurity (link is external) For more information on this vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-296574 at the following location: http://www.siemens.com/cert/advisories (link is external) 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. 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. a. CWE-400: Uncontrolled Resource Consumption (Resource Exhaustion), https://cwe.mitre.org/data/definitions/400.html, web site last accessed October 25, 2016. b. NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-7987, 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:L/PR:N/UI:N/S..., web site last accessed October 25, 2016. Contact Information For any questions related to this report, please contact ICS-CERT at: Email: email@example.com (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 firstname.lastname@example.org 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: email@example.com 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). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBWBAs7Ix+lLeg9Ub1AQgA/g//cS5ILruBuz8AlJtupSx0bHxUzp2p0dDE 8qS75UNUNFA0ZNL9ULLG2jli8bfbUSOQ85XfqXi52gp5G/7T0LvUvggbUtXzPpW7 7Uw2G7XM0YEyXbPztXHFW5PlKiYwVHq2L971fkOfZh9exElEI3SzhVuMHBITI6mV cfh0l/PC+LvIDLXvLedLg4wz11mqhts9TNidtgQrD5MBJ5D415Vj1MywYSvqX6xX a7cyeNAuaNIZ74UkoS+0pqcsgaFPMFq+CDex2YJ/B+k9/19BBT44iitVjK8c6Vkv BpxePDBBQ6zCorsJb/XLl3TscG8fOg5EFERj76fEM7pm9fgNV2hLFv6NuOctKTGs foi6XLzVVuNT0bH0hbk54X6NIaDFHNkievOy+s1RBbZW+nrTbKVqPNWt92qw7rCU T9p+B1c61YsdkWrJzYz9U3QPfUqpfIUH4/qAGfk80rOpJ9vEsvezSIifkPQ2ROeo NxjLjy0KmC42XosorJxKxcJzhNb6Vi56Wo87gsSAOnBVxBmVgO7aOwIMgrsoAn5x d1zQ6E83US9Kn5kJmHD2T4sgi4V7uimUikEwVQnupnGtvJHfUVr0tKrOR7prby9L 64QJzqL7PYA/oVNnHfrLV5oLpH72aBSxiDGoJWRqgqpFozooWiSeIroJB4eYmS4W 1fP+69NxJk4= =FxQ2 -----END PGP SIGNATURE-----