-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 # SSA-274900: Use of hardcoded key in Scalance X devices under certain conditions Publication Date: 2021-01-12 Last Update: 2021-01-12 Current Version: 1.0 CVSS v3.1 Base Score: 9.1 SUMMARY ======= Scalance X devices might not generate a unique random key after factory reset, and use a private key shipped with the firmware Siemens has released updates for some devices, is working on updates for the remaining affected products and recommends specific countermeasures until fixes are available. AFFECTED PRODUCTS AND SOLUTION ============================== * SCALANCE X-200 switch family (incl. SIPLUS NET variants) - Affected versions: All Versions - Affected by vulnerabilities: - CVE-2020-28391 - Remediation: See recommendations from section Workarounds and Mitigations * SCALANCE X-200IRT switch family (incl. SIPLUS NET variants) - Affected versions: All versions - Affected by vulnerabilities: - CVE-2020-28391 - Remediation: See recommendations from section Workarounds and Mitigations * SCALANCE X-300 switch family (incl. X408 and SIPLUS NET variants) - Affected versions: All versions < V4.1.0 - Affected by vulnerabilities: - CVE-2020-28395 - Remediation: Update to V4.1.0 or later (for supported devices) - Download: https://support.industry.siemens.com/cs/ww/en/view/109773547/ WORKAROUNDS AND MITIGATIONS =========================== Siemens has identified the following specific workarounds and mitigations that customers can apply to reduce the risk: * Update the default selfsigned device X.509 certificates with own trusted certificate * Update the default hardcoded X.509 certificates from the firmware image (fingerprints SHA-1: F2:C8:3B:8F:86:27:74:AA:60:EC:D4:A0:CF:0D:BE:A6:D1:FE:22:12 and SHA-256: 25:60:DB:B3: F9:07:9D:69:0E:DD:A9:EB:4E:1C:D5:8E:AF:79:16:C3:C8:13:A6:F6:59:AD:05:E4:6F:77:F7:72) GENERAL SECURITY RECOMMENDATIONS ================================ As a general security measure, Siemens strongly recommends to protect network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends to configure the environment according to Siemens' operational guidelines for Industrial Security (Download: https://www.siemens.com/cert/operational-guidelines-industrial-security), and to follow the recommendations in the product manuals. Additional information on Industrial Security by Siemens can be found at: https://www.siemens.com/industrialsecurity PRODUCT DESCRIPTION =================== SCALANCE X switches are used to connect industrial components like Programmable Logic Controllers (PLCs) or Human Machine Interfaces (HMIs). SIPLUS extreme products are designed for reliable operation under extreme conditions and are based on SIMATIC, LOGO!, SITOP, SINAMICS, SIMOTION, SCALANCE or other devices. SIPLUS devices use the same firmware as the product they are based on. VULNERABILITY CLASSIFICATION ============================ The vulnerability classification has been performed by using the CVSS scoring system in version 3.1 (CVSS v3.1) (https://www.first.org/cvss/). The CVSS environmental score is specific to the customer's environment and will impact the overall CVSS score. The environmental score should therefore be individually defined by the customer to accomplish final scoring. An additional classification has been performed using the CWE classification, a community-developed list of common software security weaknesses. This serves as a common language and as a baseline for weakness identification, mitigation, and prevention efforts. A detailed list of CWE classes can be found at: https://cwe.mitre.org/. * Vulnerability CVE-2020-28391 Devices create a new unique key upon factory reset, except when used with C-PLUG. When used with C-PLUG the devices use the hardcoded private RSA-key shipped with the firmware-image. An attacker could leverage this situation to a man-in-the-middle situation and decrypt previously captured traffic. CVSS v3.1 Base Score: 9.1 CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:P/RL:U/RC:C CWE: CWE-321: Use of Hard-coded Cryptographic Key * Vulnerability CVE-2020-28395 Devices do not create a new unique private key after factory reset. An attacker could leverage this situation to a man-in-the-middle situation and decrypt previously captured traffic. CVSS v3.1 Base Score: 9.1 CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:P/RL:U/RC:C CWE: CWE-321: Use of Hard-coded Cryptographic Key ADDITIONAL INFORMATION ====================== These vulnerabilities have been discovered internally by Siemens. For further inquiries on security vulnerabilities in Siemens products and solutions, please contact the Siemens ProductCERT: https://www.siemens.com/cert/advisories HISTORY DATA ============ V1.0 (2021-01-12): Publication Date TERMS OF USE ============ Siemens Security Advisories are subject to the terms and conditions contained in Siemens' underlying license terms or other applicable agreements previously agreed to with Siemens (hereinafter "License Terms"). To the extent applicable to information, software or documentation made available in or through a Siemens Security Advisory, the Terms of Use of Siemens' Global Website (https://www.siemens.com/terms_of_use, hereinafter "Terms of Use"), in particular Sections 8-10 of the Terms of Use, shall apply additionally. 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