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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2020.4532.2 Cisco IP Phone TCP Packet Flood Denial of Service Vulnerability 21 January 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco IP Phone Products Publisher: Cisco Systems Operating System: Cisco Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2020-3574 Reference: ESB-2020.3834 Original Bulletin: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-voip-phone-flood-dos-YnU9EXOv Revision History: January 21 2021: Vendor updated Fixed Software section December 23 2020: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- Cisco IP Phone TCP Packet Flood Denial of Service Vulnerability Priority: High Advisory ID: cisco-sa-voip-phone-flood-dos-YnU9EXOv First Published: 2020 November 4 16:00 GMT Last Updated: 2021 January 19 17:34 GMT Version 1.2: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvs66815 CSCvt83239 CSCvu36012 CSCvu36026 CVE Names: CVE-2020-3574 CWEs: CWE-371 Summary o A vulnerability in the TCP packet processing functionality of Cisco IP Phones could allow an unauthenticated, remote attacker to cause the phone to stop responding to incoming calls, drop connected calls, or unexpectedly reload. The vulnerability is due to insufficient TCP ingress packet rate limiting. An attacker could exploit this vulnerability by sending a high and sustained rate of crafted TCP traffic to the targeted device. A successful exploit could allow the attacker to impact operations of the phone or cause the phone to reload, leading to a denial of service (DoS) condition. Cisco has released software updates that address this vulnerability. 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-voip-phone-flood-dos-YnU9EXOv Affected Products o Vulnerable Products This vulnerability affects the following Cisco IP Phones if they are running a vulnerable firmware release: IP DECT 210 Multi-Cell Base Station with Multiplatform Firmware IP DECT 6825 with Multiplatform Firmware IP Phone 8811 Series with Multiplatform Firmware IP Phone 8841 Series with Multiplatform Firmware IP Phone 8851 Series with Multiplatform Firmware IP Phone 8861 Series with Multiplatform Firmware Unified IP Conference Phone 8831 for Third-Party Call Control Webex Room Phone Note: The default configurations of these devices are vulnerable. 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: ATA 190 Analog Telephone Adapter ATA 191 Analog Telephone Adapter IP Conference Phone 7832 IP Conference Phone 7832 with Multiplatform Firmware IP Conference Phone 8832 IP Conference Phone 8832 with Multiplatform Firmware IP Phone 6800 Series with Multiplatform Firmware IP Phone 6821 with Multiplatform Firmware IP Phone 7800 Series IP Phone 7800 Series with Multiplatform Firmware IP Phone 8800 Series IP Phone 8845 IP Phone 8865 IP Phone 8865 with Multiplatform Firmware SPA112 2-Port Phone Adapter SPA122 Analog Telephone Adapter (ATA) with Router SPA232D Multi-Line DECT Analog Telephone Adapter (ATA) SPA525G 5-Line IP Phone Unified IP Phone 3905 Unified IP Phone 6901 Unified IP Phone 6911 Unified IP Phone 7900 Series Unified IP Conference Phone 8831 Wireless IP Phone 8821 Note : The devices listed may see a performance impact from the same attack traffic, but will recover without user intervention once the attack traffic is stopped. 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 Customers are advised to upgrade to an appropriate fixed firmware release as indicated in the following table: Cisco IP Phone Model Cisco Bug First Fixed Release ID IP DECT 210 Multi-Cell Base Station with Multiplatform Firmware CSCvt83239 4.8.1 IP DECT 6825 with Multiplatform Firmware IP Phone 8811 Series with Multiplatform Firmware IP Phone 8841 Series with Multiplatform Firmware CSCvs66815 11.3.2 IP Phone 8851 Series with Multiplatform Firmware IP Phone 8861 Series with Multiplatform Firmware Unified IP Conference Phone 8831 CSCvu36012 There is no fixed firmware for Third-Party Call Control available at this time. Webex Room Phone CSCvu36026 1.2.0 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 the resolution of a Cisco TAC support case. 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-voip-phone-flood-dos-YnU9EXOv Revision History o +---------+-----------------------------+----------+--------+-------------+ | Version | Description | Section | Status | Date | +---------+-----------------------------+----------+--------+-------------+ | | Updated the Fixed Software | | | | | 1.2 | section to indicate fix | Fixed | Final | 2021-JAN-19 | | | released for Webex Room | Software | | | | | Phone. | | | | +---------+-----------------------------+----------+--------+-------------+ | | Updated the Fixed Software | Fixed | | | | 1.1 | section for the Webex Room | Software | Final | 2020-DEC-22 | | | Phone. | | | | +---------+-----------------------------+----------+--------+-------------+ | 1.0 | Initial public release. | - | Final | 2020-NOV-04 | +---------+-----------------------------+----------+--------+-------------+ - --------------------------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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