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Siemens has released an advisory to inform its users how to mitigate vulnerabilities that affect SIMATIC CP 1543-1. These vulnerabilities were coordinated directly with Siemens by SOGETI and Agence nationale de la sécurité des systèmes d’information (ANSSI). Siemens has produced a firmware to mitigate these vulnerabilities.
These vulnerabilities could be exploited remotely.
Siemens reports that the vulnerabilities affect the following versions of SIMATIC CP 1543-1:
- SIMATIC CP 1543-1: All versions prior to V2.0.28
An attacker who exploits these vulnerabilities may be able to elevate privileges on the affected devices or cause a denial-of-service condition.
Impact to individual organizations depends on many factors that are unique to each organization. NCCIC/ICS-CERT recommends that organizations evaluate the impact of these vulnerabilities based on their operational environment, architecture, and product implementation.
Siemens is a multinational company headquartered in Munich, Germany.
The affected product, SIMATIC CP 1543-1 communication processor, connects the S7-1500 controller to Ethernet networks. It provides integrated security functions, such as firewall and virtual private networks (VPNs), and supports other protocols with data encryption such as FTP. The communication processor protects S7-1500 stations against unauthorized access, as well as integrity and confidentiality of transmitted data. According to Siemens, this product is deployed across several sectors including Chemical, Energy, Food and Agriculture, and Water and Wastewater Systems. Siemens estimates that these products are used worldwide.
IMPROPER INPUT VALIDATIONa
Users with elevated privileges to TIA-Portal and project data on the engineering station could possibly get privileged access on affected devices.
IMPROPER PRIVILEGE MANAGEMENTd
Under special conditions, it may be possible to write SNMP variables on Port 161/UDP that should be read-only and should only be configured with TIA-Portal. A write to these variables could reduce the availability or cause a denial of service.
These vulnerabilities could be exploited remotely.
EXISTENCE OF EXPLOIT
No known public exploits specifically target these vulnerabilities.
Crafting a working exploit for these vulnerabilities would be difficult.
Siemens provides firmware update V2.0.28 for SIMATIC CP 1543-1 devices, which fixes the vulnerabilities, and recommends users update to the new version. This update can be found on the Siemens web site at the following location:
Siemens strongly recommends users protect network access to the management interface of perimeter devices with appropriate mechanisms. Siemens also advises that users configure the operational environment according to Siemens’ Operational Guidelines for Industrial Security:
For more information on this vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-672373 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. 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-20: Improper Input Validation, https://cwe.mitre.org/data/definitions/20.html, web site last accessed November 22, 2016.
- b. NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8561, web site last accessed November 22, 2016.
- c. CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H, web site last accessed November 22, 2016.
- d. CWE-269: Improper Privilege Management, https://cwe.mitre.org/data/definitions/269.html, web site last accessed November 22, 2016.
- e. NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8562, web site last accessed November 22, 2016.
- f. CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H, web site last accessed November 22, 2016.
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