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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2020.2698.2 Cisco Small Business Smart and Managed Switches Denial of Service Vulnerability 7 September 2020 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco Small Business Smart and Managed Switches Publisher: Cisco Systems Operating System: Cisco Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2020-3363 Original Bulletin: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sbss-ipv6-dos-3bLk6vA Revision History: September 7 2020: Removed Cisco Small Business 200, 300 and 500 Series Swiches from the list of vulnerable products August 6 2020: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- Cisco Small Business Smart and Managed Switches Denial of Service Vulnerability Priority: High Advisory ID: cisco-sa-sbss-ipv6-dos-3bLk6vA First Published: 2020 August 5 16:00 GMT Last Updated: 2020 September 4 14:34 GMT Version 1.1: Final Workarounds: No workarounds availableCisco Bug IDs: CSCvt45834 CVE-2020-3363 CVSS Score: 8.6 AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X Summary o A vulnerability in the IPv6 packet processing engine of Cisco Small Business Smart and Managed Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient validation of incoming IPv6 traffic. An attacker could exploit this vulnerability by sending a crafted IPv6 packet through an affected device. A successful exploit could allow the attacker to cause an unexpected reboot of the switch, leading to a DoS condition. This vulnerability is specific to IPv6 traffic. IPv4 traffic is not affected. Cisco has released software updates that address this vulnerability for devices that have not reached the end of software maintenance. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/ cisco-sa-sbss-ipv6-dos-3bLk6vA Affected Products o Vulnerable Products This vulnerability affects the following Cisco products if they are running a vulnerable software release: 250 Series Smart Switches 350 Series Managed Switches 350X Series Stackable Managed Switches 550X Series Stackable Managed Switches For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory. Products Confirmed Not Vulnerable Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability. Cisco has confirmed that this vulnerability does not affect the following Cisco products: Small Business 200 Series Smart Switches Small Business 300 Series Managed Switches Small Business 500 Series Stackable Managed Switches Workarounds o There are no workarounds that address this vulnerability. Fixed Software o Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license: https://www.cisco.com/c/en/us/products/ end-user-license-agreement.html Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades. When considering software upgrades , customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page , to determine exposure and a complete upgrade solution. In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers. Customers Without Service Contracts Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c /en/us/support/web/tsd-cisco-worldwide-contacts.html Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade. Fixed Releases Cisco fixed this vulnerability in Release 2.5.5.47 for the following Cisco products: 250 Series Smart Switches 350 Series Managed Switches 350X Series Stackable Managed Switches 550X Series Stackable Managed Switches Customers can download the firmware from the Software Center on Cisco.com by clicking Browse all and navigating to Switches > LAN Switches - Small Business . Exploitation and Public Announcements o The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory. Source o This vulnerability was found during internal security testing. Cisco Security Vulnerability Policy o To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy . This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco. URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/ cisco-sa-sbss-ipv6-dos-3bLk6vA Revision History o +---------+---------------------------+------------+--------+-------------+ | Version | Description | Section | Status | Date | +---------+---------------------------+------------+--------+-------------+ | | Removed Cisco Small | Affected | | | | | Business 200, 300, and | Products | | | | 1.1 | 500 Series Switches from | and Fixed | Final | 2020-SEP-04 | | | the list of vulnerable | Releases | | | | | products. | | | | +---------+---------------------------+------------+--------+-------------+ | 1.0 | Initial public release. | - | Final | 2020-AUG-05 | +---------+---------------------------+------------+--------+-------------+ - --------------------------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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