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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2019.4402.2 Cisco IOS XR Software NETCONF Over Secure Shell ACL Bypass Vulnerability 25 November 2019 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco IOS XR Publisher: Cisco Systems Operating System: Cisco Impact/Access: Unauthorised Access -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2019-15998 Original Bulletin: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20191120-iosxr-ssh-bypass Revision History: November 25 2019: Vendor updated affected versions & added instructions for requesting update November 21 2019: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- Cisco IOS XR Software NETCONF Over Secure Shell ACL Bypass Vulnerability Priority: Medium Advisory ID: cisco-sa-20191120-iosxr-ssh-bypass First Published: 2019 November 20 16:00 GMT Last Updated: 2019 November 23 02:24 GMT Version 1.1: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvp91299 CVE-2019-15998 CWE-284 CVSS Score: 5.3 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:X/RL:X/RC:X Summary o A vulnerability in the access-control logic of the NETCONF over Secure Shell (SSH) of Cisco IOS XR Software may allow connections despite an access control list (ACL) that is configured to deny access to the NETCONF over SSH of an affected device. The vulnerability is due to a missing check in the NETCONF over SSH access control list (ACL). An attacker could exploit this vulnerability by connecting to an affected device using NETCONF over SSH. A successful exploit could allow the attacker to connect to the device on the NETCONF port. Valid credentials are required to access the device. This vulnerability does not affect connections to the default SSH process on the 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-20191120-iosxr-ssh-bypass Affected Products o Vulnerable Products At the time of publication, this vulnerability affected Cisco IOS XR Software releases 6.5.1, 6.5.2, and 6.5.3. This vulnerability does not affect any other releases. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information. 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 Cisco IOS Software or Cisco IOS XE Software. Workarounds o There are no workarounds that address this vulnerability. Fixed Software o When considering software upgrades , customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts 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. Fixed Releases At the time of publication, Cisco IOS XR Software Release 6.5.3 with SMU and later contained the fix for this vulnerability. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information. Customers can download the SMU from the Software Center by doing the following: 1. Click Browse all . 2. Choose Routers > Service Provider Edge Routers . 3. Choose the specific router family from the right pane of the product selector. 4. Choose a specific product from the right pane of the product selector. 5. Choose Software on Chassis > IOS XR Software Maintenance Upgrades (SMU) - 6.5.3 . 6. Click the download link for the Hitless/Optional SMU, ACL under 'ssh server netconf' did not take effect release. If the SMU is not listed for your required platform, contact your account team or the Cisco TAC to request an SMU for your platform. 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-20191120-iosxr-ssh-bypass Revision History o +---------+---------------------+-------------+--------+------------------+ | Version | Description | Section | Status | Date | +---------+---------------------+-------------+--------+------------------+ | | Clarified affected | Vulnerable | | | | 1.1 | releases. Added | Products | Final | 2019-November-23 | | | instructions for | and Fixed | | | | | requesting an SMU. | Releases | | | +---------+---------------------+-------------+--------+------------------+ | 1.0 | Initial public | - | Final | 2019-November-20 | | | release. | | | | +---------+---------------------+-------------+--------+------------------+ - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. 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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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