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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.2054 Advisory (icsa-21-159-10) Siemens SIMATIC TIM libcurl 9 June 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Siemens SIMATIC TIM libcurl Publisher: ICS-CERT Operating System: Network Appliance Impact/Access: Access Confidential Data -- Remote/Unauthenticated Reduced Security -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2020-8286 CVE-2020-8169 Reference: ASB-2021.0073 ESB-2021.1866 Original Bulletin: https://us-cert.cisa.gov/ics/advisories/icsa-21-159-10 - --------------------------BEGIN INCLUDED TEXT-------------------- ICS Advisory (ICSA-21-159-10) Siemens SIMATIC TIM libcurl Original release date: June 08, 2021 Legal Notice All information products included in https://us-cert.cisa.gov/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://us-cert.cisa.gov/tlp/ . 1. EXECUTIVE SUMMARY o CVSS v3 7.5 o ATTENTION: Exploitable remotely/low attack complexity o Vendor: Siemens o Equipment: SIMATIC TIM libcurl o Vulnerabilities: Exposure of Sensitive Information to an Unauthorized Actor, Improper Certificate Validation 2. RISK EVALUATION Successful exploitation of these third-party vulnerabilities could allow an attacker to extract sensitive information and pass a revoked certificate as valid. 3. TECHNICAL DETAILS 3.1 AFFECTED PRODUCTS The following devices are affected by the third-party component libcurl: o SIMATIC TIM 1531 IRC (incl. SIPLUS NET variants), All versions prior to v2.2 3.2 VULNERABILITY OVERVIEW 3.2.1 EXPOSURE OF SENSITIVE INFORMATION TO AN UNAUTHORIZED ACTOR CWE-200 The libcurl library Versions 7.62.0 to and including 7.70.0 are vulnerable to an information disclosure vulnerability that can lead to a partial password being leaked over the network and to DNS servers. CVE-2020-8169 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:N ). 3.2.2 IMPROPER CERTIFICATE VALIDATION CWE-295 The libcurl library Versions 7.41.0 to 7.73.0 are vulnerable to an improper check for certificate revocation due to insufficient verification of the OCSP response. This vulnerability could allow an attacker to pass a revoked certificate as valid. CVE-2020-8286 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:H/A:N ). 3.3 BACKGROUND o CRITICAL INFRASTRUCTURE SECTORS: Multiple o COUNTRIES/AREAS DEPLOYED: Worldwide o COMPANY HEADQUARTERS LOCATION: Germany 3.4 RESEARCHER Siemens reported these vulnerabilities to CISA. 4. MITIGATIONS Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk: o Update to v2.2 or later version o Restrict access to the device to the internal or VPN network and to trusted IP addresses only Additional information on industrial security by Siemens can be found at: https://www.siemens.com/industrialsecurity For more information see Siemens Security Advisory SSA-200951 CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities. Specifically, users should: o Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet . o Locate control system networks and remote devices behind firewalls, and isolate them from the business network. o When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as its 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 on the ICS webpage on us-cert.cisa.gov . 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 on the ICS webpage on us-cert.cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies . 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. CISA also recommends users take the following measures to protect themselves from social engineering attacks: o Do not click web links or open unsolicited attachments in email messages. o Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams. o Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks. No known public exploits specifically target these vulnerabilities. For any questions related to this report, please contact the CISA at: Email: CISAservicedesk@cisa.dhs.gov Toll Free: 1-888-282-0870 CISA 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 auscert@auscert.org.au 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: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au 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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