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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.2961 Cisco Enterprise NFV Infrastructure Software Authentication Bypass Vulnerability 2 September 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Enterprise NFV Infrastructure Software (NFVIS) Publisher: Cisco Systems Operating System: Cisco Impact/Access: Administrator Compromise -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2021-34746 Original Bulletin: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nfvis-g2DMVVh - --------------------------BEGIN INCLUDED TEXT-------------------- Cisco Enterprise NFV Infrastructure Software Authentication Bypass Vulnerability Priority: Critical Advisory ID: cisco-sa-nfvis-g2DMVVh First Published: 2021 September 1 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvz16015 CVE Names: CVE-2021-34746 CWEs: CWE-289 Summary o A vulnerability in the TACACS+ authentication, authorization and accounting (AAA) feature of Cisco Enterprise NFV Infrastructure Software (NFVIS) could allow an unauthenticated, remote attacker to bypass authentication and log in to an affected device as an administrator. This vulnerability is due to incomplete validation of user-supplied input that is passed to an authentication script. An attacker could exploit this vulnerability by injecting parameters into an authentication request. A successful exploit could allow the attacker to bypass authentication and log in as an administrator to the affected device. 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-nfvis-g2DMVVh Affected Products o Vulnerable Products This vulnerability affects Cisco Enterprise NFVIS Release 4.5.1 if the TACACS external authentication method is configured. Determine TACACS External Authentication Configuration To determine if a TACACS external authentication feature is enabled on a device, use the show running-config tacacs-server command. The following example shows the output of the show running-config tacacs-server command on Cisco Enterprise NFVIS when TACACS external authentication is enabled: nfvis# show running-config tacacs-server tacacs-server host 192.168.1.1 key 0 shared-secret "example!23" admin-priv 15 oper-priv 1 ! nfvis# If the output of the show running-config tacacs-server command is No entries found , the TACACS external authentication feature is not enabled. Alternatively, check the configuration through the GUI. Choose Configuration > Host > Security > User and Roles . If a TACACS+ host is defined under External Authentication , the device is considered to be vulnerable. Configurations that are using RADIUS or local authentication only are not affected. Products Confirmed Not Vulnerable Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability. 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 Cisco Enterprise NFVIS releases 4.6.1 and later. Exploitation and Public Announcements o The Cisco Product Security Incident Response Team (PSIRT) is aware that proof-of-concept exploit code is available for the vulnerability described in this advisory. The Cisco PSIRT is not aware of any malicious use of the vulnerability that is described in this advisory. Source o Cisco would like to thank Cyrille Chatras of Orange Group for reporting this vulnerability. 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-nfvis-g2DMVVh Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2021-SEP-01 | +----------+---------------------------+----------+--------+--------------+ - --------------------------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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