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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.3022.5 Cisco IOS XR Software Vulnerabilities 21 October 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco IOS XR Software Publisher: Cisco Systems Operating System: Cisco Impact/Access: Root Compromise -- Existing Account Execute Arbitrary Code/Commands -- Existing Account Overwrite Arbitrary Files -- Existing Account Denial of Service -- Remote/Unauthenticated Access Confidential Data -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2021-34771 CVE-2021-34737 CVE-2021-34728 CVE-2021-34722 CVE-2021-34721 CVE-2021-34720 CVE-2021-34719 CVE-2021-34718 CVE-2021-34713 CVE-2021-34709 CVE-2021-34708 CVE-2021-1440 Original Bulletin: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-scp-inject-QwZOCv2 https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-privescal-dZYMrKf https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xrbgp-rpki-dos-gvmjqxbk https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-cmd-inj-wbZKvPxc https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dhcp-dos-pjPVReLU https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ipsla-ZA3SRrpP https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-infodisc-CjLdGMc5 https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-npspin-QYpwdhFD https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lnt-QN9mCzwn Revision History: October 21 2021: Clarified vulnerable releases September 20 2021: Added SMU Table. September 17 2021: Vendor added additional SMUs. September 16 2021: Added additional SMUs September 9 2021: Initial Release - --------------------------BEGIN INCLUDED TEXT-------------------- Cisco IOS XR Software Arbitrary File Read and Write Vulnerability Priority: High Advisory ID: cisco-sa-iosxr-scp-inject-QwZOCv2 First Published: 2021 September 8 16:00 GMT Last Updated: 2021 September 16 18:27 GMT Version 1.1: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvx48017 CVE Names: CVE-2021-34718 CWEs: CWE-88 Summary o A vulnerability in the SSH Server process of Cisco IOS XR Software could allow an authenticated, remote attacker to overwrite and read arbitrary files on the local device. This vulnerability is due to insufficient input validation of arguments that are supplied by the user for a specific file transfer method. An attacker with lower-level privileges could exploit this vulnerability by specifying Secure Copy Protocol (SCP) parameters when authenticating to a device. A successful exploit could allow the attacker to elevate their privileges and retrieve and upload files on a device that they should not have access to. 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-iosxr-scp-inject-QwZOCv2 This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication . Affected Products o Vulnerable Products This vulnerability affects Cisco IOS XR Software releases earlier than Release 7.3.2 and Release 7.4.1. 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: IOS Software IOS XE Software NX-OS Software 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 IOS XR Software releases 7.3.2 and 7.4.1. Cisco has released the following SMUs to address this vulnerability. Customers who require SMUs for platforms or releases that are not listed are advised to contact their support organization. Cisco IOS XR Software Release Platform SMU Name 6.2.3 ASR9K-PX asr9k-px-6.2.3.CSCvx48017 6.3.3 ASR9K-PX asr9k-px-6.3.3.CSCvx48017 6.3.15 NCS5500 ncs5500-6.3.15.CSCvx48017 6.4.2 ASR9K-PX asr9k-px-6.4.2.CSCvx48017 6.5.2 NCS5500 ncs5500-6.5.2.CSCvx48017 6.5.3 ASR9K-PX asr9k-px-6.5.3.CSCvx48017 6.5.3 XRV9K xrv9k-6.5.3.CSCvx48017 6.6.12 IOSXRWBD iosxrwbd-6.6.12.CSCvx48017 6.6.25 NCS5500 ncs5500-6.6.25.CSCvx48017 6.6.3 IOSXRWBD iosxrwbd-6.6.3.CSCvx48017 6.6.3 NCS5500 ncs5500-6.6.3.CSCvx48017 6.7.3 ASR9K-PX asr9k-px-6.7.3.CSCvx48017 6.7.4 CRS-PX hfr-px-6.7.4.CSCvx48017 7.0.1 NCS5500 ncs5500-7.0.1.CSCvx48017 7.2.1 IOSXRWBD iosxrwbd-7.2.1.CSCvx48017 7.2.1 NCS1001 ncs1001-7.2.1.CSCvx48017 7.2.2 IOSXRWBD iosxrwbd-7.2.2.CSCvx48017 7.2.2 NCS5500 ncs5500-7.2.2.CSCvx48017 7.2.2 XRV9K xrv9k-7.2.2.CSCvx48017 7.1.2 XRV9K xrv9k-7.1.2.CSCvx48017 7.1.2 NCS5500 ncs5500-7.1.2.CSCvx48017 7.1.2 NCS560 ncs560-7.1.2.CSCvx48017 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. Related to This Advisory o Cisco Event Response: September 2021 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-scp-inject-QwZOCv2 Revision History o +---------+------------------------+---------------+--------+-------------+ | Version | Description | Section | Status | Date | +---------+------------------------+---------------+--------+-------------+ | 1.1 | Added additional SMUs. | Fixed | Final | 2021-SEP-16 | | | | Software | | | +---------+------------------------+---------------+--------+-------------+ | 1.0 | Initial public | - | Final | 2021-SEP-08 | | | release. | | | | +---------+------------------------+---------------+--------+-------------+ - -------------------------------------------------------------------------------- Cisco IOS XR Software Authenticated User Privilege Escalation Vulnerabilities Priority: High Advisory ID: cisco-sa-iosxr-privescal-dZYMrKf First Published: 2021 September 8 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvx48004 CSCvx48007 CVE Names: CVE-2021-34719 CVE-2021-34728 CWEs: CWE-78 Summary o Multiple vulnerabilities in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker with a low-privileged account to elevate privileges on an affected device. For more information about these vulnerabilities, see the Details section of this advisory. Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-privescal-dZYMrKf This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication . Affected Products o Vulnerable Products These vulnerabilities affect Cisco IOS XR Software releases earlier than Release 7.3.2 and earlier than Release 7.4.1. Products Confirmed Not Vulnerable Only products listed in the Vulnerable Products section of this advisory are known to be affected by these vulnerabilities. Cisco has confirmed that these vulnerabilities do not affect the following Cisco products: IOS Software IOS XE Software NX-OS Software Details o The vulnerabilities are not dependent on one another. Exploitation of one of the vulnerabilities is not required to exploit another vulnerability. In addition, a software release that is affected by one of the vulnerabilities may not be affected by the other vulnerabilities. Details about the vulnerabilities are as follows: CVE-2021-34728: Cisco IOS XR Software Privilege Escalation Vulnerability A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to elevate privileges on an affected device. The vulnerability is due to insufficient input validation of commands that are supplied by a user. An attacker with a low-privileged account could exploit this vulnerability by using crafted commands at the prompt. A successful exploit could allow the attacker to elevate privileges to root . Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. Bug ID(s): CSCvx48007 CVE ID: CVE-2021-34728 Security Impact Rating (SIR): High CVSS Base Score: 7.8 CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVE-2021-34719: Cisco IOS XR Software Privilege Escalation Vulnerability A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to elevate privileges to root on an affected device. This vulnerability is due to insufficient validation of command line arguments. An attacker could exploit this vulnerability by authenticating to an affected device and submitting crafted input to a specific command on the device. A successful exploit could allow the attacker to execute arbitrary commands as root . Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. Bug ID(s): CSCvx48004 CVE ID: CVE-2021-34719 Security Impact Rating (SIR): High CVSS Base Score: 7.8 CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Workarounds o There are no workarounds that address these vulnerabilities. Fixed Software o Cisco has released free software updates that address the vulnerabilities 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 these vulnerabilities in the following Cisco IOS XR Software releases: 7.3.2 and later 7.4.1 and later 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 vulnerabilities that are described in this advisory. Source o These vulnerabilities were 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. Related to This Advisory o Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-privescal-dZYMrKf Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2021-SEP-08 | +----------+---------------------------+----------+--------+--------------+ - -------------------------------------------------------------------------------- Cisco IOS XR Software Border Gateway Protocol Resource Public Key Infrastructure Denial of Service Vulnerability Priority: Medium Advisory ID: cisco-sa-xrbgp-rpki-dos-gvmjqxbk First Published: 2021 September 8 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvx04451 CVE Names: CVE-2021-1440 CWEs: CWE-617 Summary o A vulnerability in the implementation of the Resource Public Key Infrastructure (RPKI) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause the Border Gateway Protocol (BGP) process to crash, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of a specific RPKI to Router (RTR) Protocol packet header. An attacker could exploit this vulnerability by compromising the RPKI validator server and sending a specifically crafted RTR packet to an affected device. Alternatively, the attacker could use man-in-the-middle techniques to impersonate the RPKI validator server and send a specifically crafted RTR response packet over the established RTR TCP connection to the affected device. A successful exploit could allow the attacker to cause a DoS condition because the BGP process could constantly restart and BGP routing could become unstable. 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-xrbgp-rpki-dos-gvmjqxbk This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication . Affected Products o Vulnerable Products At the time of publication, this vulnerability affected Cisco devices if they were running Cisco IOS XR Software releases 4.3.0 through 7.3.0 and had RPKI configured and in use. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information. Determine the RPKI Device Configuration To determine if an RPKI server is configured, issue the show running-config router bgp CLI command. If the rpki server command is displayed, as shown in the following example, the device could be vulnerable: iosxr# show running-config router bgp . . . rpki server 192.168.1.100 Then, to determine if there is an active RPKI server, issue the show bgp rpki server summary CLI command. If an RPKI server TCP connection is in ESTAB state, as shown in the following example, the device is affected by this vulnerability: iosxr# show bgp rpki server summary Wed Aug 13 13:25:04.368 utc Hostname/Address Transport State Time ROAs (IPv4/IPv6) 10.112.255.14 TCP:323 CONNECT 00:00:06 N/A 2001:400:6:1::1 TCP:323 ESTAB 01:06:51 181152/30503 Note : If the command does not return output, RPKI is not configured. However, if the command returns output but none of the RPKI servers have a connection in ESTAB state, the device could become vulnerable if the connection becomes established. 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: IOS Software IOS XE Software NX-OS Software Workarounds o There are no workarounds that address this vulnerability. However, administrators can remove the RPKI configuration as a mitigation. If RPKI servers are either not in use or removed from the configuration, the device is considered not vulnerable. The decision to remove the RPKI configuration needs careful consideration. While this mitigation has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment. 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 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, the following Cisco IOS XR Software releases contained the fix for this vulnerability: 7.3.1 and later 7.3.15 and later 7.4.1 and later At the time of publication, Cisco had released the following SMUs to address this vulnerability. Customers who require SMUs for platforms or releases that are not listed are advised to contact their support organization. Cisco IOS XR Software Release Platform SMU Name 6.5.3 ASR9K-PX asr9k-px-6.5.3.CSCvx04451 6.7.4 CRS-PX hfr-px-6.7.4.CSCvx04451 7.0.2 ASR9K-X64 asr9k-x64-7.0.2.CSCvx04451 7.1.2 ASR9K-X64 asr9k-x64-7.1.2.CSCvx04451 See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information, including SMU availability. 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. Related to This Advisory o Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xrbgp-rpki-dos-gvmjqxbk Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2021-SEP-08 | +----------+---------------------------+----------+--------+--------------+ - -------------------------------------------------------------------------------- Cisco IOS XR Software Command Injection Vulnerabilities Priority: Medium Advisory ID: cisco-sa-iosxr-cmd-inj-wbZKvPxc First Published: 2021 September 8 16:00 GMT Last Updated: 2021 September 17 17:22 GMT Version 1.1: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvx48001 CSCvx48002 CVE Names: CVE-2021-34721 CVE-2021-34722 CWEs: CWE-78 CWE-88 Summary o Multiple vulnerabilities in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to gain access to the underlying root shell of an affected device and execute arbitrary commands with root privileges. For more information about these vulnerabilities, see the Details section of this advisory. Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-cmd-inj-wbZKvPxc This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication . Affected Products o Vulnerable Products At the time of publication, CVE-2021-34721 affected Cisco IOS XR Software releases earlier than Release 7.3.2 if the xml agent feature was configured. At the time of publication, CVE-2021-34722 affected Cisco IOS XR Software releases 7.1.1 through 7.3.1. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information. Determine the Device Configuration To determine if the xml agent is enabled, use the following command: RP/0/RP0/CPU0: router# show running-config | include xml agent xml agent tty Products Confirmed Not Vulnerable Only products listed in the Vulnerable Products section of this advisory are known to be affected by these vulnerabilities. Cisco has confirmed that these vulnerabilities do not affect the following Cisco products: IOS Software IOS XE Software NX-OS Software Details o The vulnerabilities are not dependent on one another. Exploitation of one of the vulnerabilities is not required to exploit another vulnerability. In addition, a software release that is affected by one of the vulnerabilities may not be affected by the other vulnerabilities. Details about the vulnerabilities are as follows: CVE-2021-34721: Cisco IOS XR Software Command Injection Vulnerability A vulnerability in the XML configuration manager of Cisco IOS XR Software could allow an authenticated, local attacker to inject arbitrary commands that are executed with root privileges on the underlying Linux operating system (OS) of an affected device. This vulnerability is due to insufficient input validation of commands that are supplied by a user. An attacker could exploit this vulnerability by authenticating to a device and submitting crafted input to affected commands. A successful exploit could allow an attacker to gain access to the underlying root shell of the affected device and execute arbitrary commands as root . Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. Bug ID(s): CSCvx48002 CVE ID: CVE-2021-34721 Security Impact Rating (SIR): Medium CVSS Base Score: 6.7 CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H CVE-2021-34722: Cisco IOS XR Software Command Injection Vulnerability A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to gain access to the root shell of an affected device and execute arbitrary commands with root privileges. The vulnerability exists because the affected software improperly sanitizes command arguments. An attacker could exploit this vulnerability by authenticating to the device and using CLI commands that contain crafted arguments. A successful exploit could allow the attacker to gain access to the underlying root shell of the affected device and execute arbitrary commands with root privileges. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. Bug ID(s): CSCvx48001 CVE ID: CVE-2021-34722 Security Impact Rating (SIR): Medium CVSS Base Score: 6.7 CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H Workarounds o There are no workarounds that address these vulnerabilities. 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 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, the following Cisco IOS XR Software releases contained the fix for these vulnerabilities: 7.3.2 and later 7.4.1 and later Cisco has released the following SMUs to address these vulnerabilities. Customers who require SMUs for platforms or releases that are not listed are advised to contact their support organization. The SMUs in the following table address Cisco Bug ID CSCvx48002 . Cisco IOS XR Software Release Platform SMU Name 6.6.3 IOSXRWBD iosxrwbd-6.6.3.CSCvx48002 7.0.1 NCS5500 ncs5500-7.0.1.CSCvx48002 7.2.1 ASR9K-X64 asr9k-x64-7.1.3.CSCvw95930 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 vulnerabilities that are described in this advisory. Source o These vulnerabilities were 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. Related to This Advisory o Cisco Event Response: September 2021 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-cmd-inj-wbZKvPxc Revision History o +---------+------------------------+---------------+--------+-------------+ | Version | Description | Section | Status | Date | +---------+------------------------+---------------+--------+-------------+ | 1.1 | Added SMU table. | Fixed | Final | 2021-SEP-17 | | | | Software | | | +---------+------------------------+---------------+--------+-------------+ | 1.0 | Initial public | - | Final | 2021-SEP-08 | | | release. | | | | +---------+------------------------+---------------+--------+-------------+ - -------------------------------------------------------------------------------- Cisco IOS XR Software DHCP Version 4 Server Denial of Service Vulnerability Priority: Medium Advisory ID: cisco-sa-iosxr-dhcp-dos-pjPVReLU First Published: 2021 September 8 16:00 GMT Last Updated: 2021 October 20 17:55 GMT Version 1.1: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvw95930 CVE Names: CVE-2021-34737 CWEs: CWE-476 Summary o A vulnerability in the DHCP version 4 (DHCPv4) server feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to trigger a crash of the dhcpd process, resulting in a denial of service (DoS) condition. This vulnerability exists because certain DHCPv4 messages are improperly validated when they are processed by an affected device. An attacker could exploit this vulnerability by sending a malformed DHCPv4 message to an affected device. A successful exploit could allow the attacker to cause a NULL pointer dereference, resulting in a crash of the dhcpd process. While the dhcpd process is restarting, which may take up to approximately two minutes, DHCPv4 server services are unavailable on the affected device. This could temporarily prevent network access to clients that join the network during that time period. Note: Only the dhcpd process crashes and eventually restarts automatically. The router does not reload. 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-iosxr-dhcp-dos-pjPVReLU This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication . Affected Products o Vulnerable Products At the time of publication, this vulnerability affected the following Cisco products if they were running Cisco IOS XR Software releases 6.7.2 and later, 7.1.2 and later, or 7.2.1 and later but earlier than Release 7.3.2 or earlier than Release 7.4.1 and had the DHCPv4 server feature or the DHCPv4 proxy feature enabled: ASR 9000 Series Aggregation Services Routers IOS XRv 9000 Routers Network Convergence System (NCS) 540 Series Routers NCS 560 Series Routers NCS 5000 Series Routers NCS 5500 Series Routers See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information. Determine the DHCPv4 Configuration To determine whether the DHCPv4 server feature or the DHCPv4 proxy feature is enabled on a device, run the show running-config dhcp ipv4 command in privileged EXEC mode on the device CLI and check for a server profile that is either directly or indirectly (through a base profile) bound to at least one interface. The following example shows the output of the show running-config dhcp ipv4 command on a device that has the DHCPv4 server profile TEST directly bound to interface GigabitEthernet0/0/0/0: dhcp ipv4 profile TEST server . . . ! interface GigabitEthernet0/0/0/0 server profile TEST The following example shows the output of the show running-config dhcp ipv4 command on a device that has the DHCPv4 server profiles DHCP_SERVER and DEFAULT_PROFILE indirectly bound to interface GigabitEthernet0/0/0/0 through base profile DHCP_BASE : dhcp ipv4 profile DHCP_BASE base match option 60 41424355 profile DHCP_SERVER server default profile DEFAULT_PROFILE server . . . ! profile DHCP_SERVER server . . . ! profile DEFAULT_PROFILE server . . . ! interface GigabitEthernet0/0/0/0 base profile DHCP_BASE The following example shows the output of the show running-config dhcp ipv4 command on a device that has the DHCPv4 proxy profile PROXY directly bound to interface GigabitEthernet0/0/0/0: dhcp ipv4 profile PROXY proxy helper-address vrf default 192.168.23.7 giaddr 192.168.23.11 ! interface GigabitEthernet0/0/0/0 proxy profile PROXY 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: IOS Software IOS XE Software NX-OS 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 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, the following Cisco IOS XR Software releases contained the fix for this vulnerability: 7.3.2 and later 7.4.1 and later Cisco has released the following SMU to address this vulnerability. Customers who require SMUs for platforms or releases that are not listed are advised to contact their support organization. Cisco IOS XR Software Release Platform SMU Name 7.1.3 ASR9K-X64 asr9k-x64-7.1.3.CSCvw95930 See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information, including SMU availability. 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. Related to This Advisory o Cisco Event Response: September 2021 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dhcp-dos-pjPVReLU Revision History o +---------+-----------------------+----------------+--------+-------------+ | Version | Description | Section | Status | Date | +---------+-----------------------+----------------+--------+-------------+ | 1.1 | Clarified vulnerable | Vulnerable | Final | 2021-OCT-20 | | | releases. | Products | | | +---------+-----------------------+----------------+--------+-------------+ | 1.0 | Initial public | - | Final | 2021-SEP-08 | | | release. | | | | +---------+-----------------------+----------------+--------+-------------+ - -------------------------------------------------------------------------------- Cisco IOS XR Software IP Service Level Agreements and Two-Way Active Measurement Protocol Denial of Service Vulnerability Priority: High Advisory ID: cisco-sa-ipsla-ZA3SRrpP First Published: 2021 September 8 16:00 GMT Last Updated: 2021 September 15 15:02 GMT Version 1.1: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvw32825 CSCvw61840 CVE Names: CVE-2021-34720 CWEs: CWE-771 Summary o A vulnerability in the IP Service Level Agreements (IP SLA) responder and Two-Way Active Measurement Protocol (TWAMP) features of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause device packet memory to become exhausted or cause the IP SLA process to crash, resulting in a denial of service (DoS) condition. This vulnerability exists because socket creation failures are mishandled during the IP SLA and TWAMP processes. An attacker could exploit this vulnerability by sending specific IP SLA or TWAMP packets to an affected device. A successful exploit could allow the attacker to exhaust the packet memory, which will impact other processes, such as routing protocols, or crash the IP SLA process. 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-ipsla-ZA3SRrpP This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication . Affected Products o Vulnerable Products This vulnerability affects Cisco devices if they are running a vulnerable release of Cisco IOS XR Software and have the IP SLA responder feature enabled. For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory. Determine the IP SLA Responder Configuration To determine whether the IP SLA responder is enabled on a device, use the show running-config ipsla CLI command. If the IP SLA feature is configured with the keywords responder or responder twamp , the device is affected by this vulnerability. The following example shows the output for a device that has the IP SLA responder enabled: RP/0/RP0/CPU0:IOSXR# show running-config ipsla ipsla responder ! RP/0/RP0/CPU0:IOSXR# The following example shows the output for a device that has the IP SLA responder enabled with TWAMP: RP/0/RP0/CPU0:IOSXR# show running-config ipsla ipsla responder twamp ! RP/0/RP0/CPU0:IOSXR# Note: Devices that are configured purely as initiators in the IP SLA process with the ipsla operation are not affected unless they also have the responder or responder twamp configured. 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: IOS Software IOS XE Software NX-OS Software Workarounds o There are no workarounds that address this vulnerability. However, administrators may choose to do the following as a mitigation: If IP SLA responder is configured with a key chain and a key-string password, then only authenticated attackers can exploit this vulnerability. To enable authentication on the IP SLA responder, use the show running-config ipsla and the show run key chain commands, as shown in the following example: RP/0/RP0/CPU0:IOSXR# show running-config ipsla ipsla key-chain 1 responder ! ! RP/0/RP0/CPU0:IOSXR# RP/0/RP0/CPU0:IOSXR#show run key chain key chain 1 key 1 key-string password 060506324F41584B56 ! ! While this mitigation has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment. 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 In the following table, the left column lists Cisco software release trains. The center column indicates which specific releases are affected by this vulnerability. The right column indicates the first fixed release. Cisco IOS XR Affected First Fixed Release for This Vulnerability Software Releases Release 5.3 and All Migrate to a fixed release. earlier 6.0 All Migrate to a fixed release. 6.1 All Migrate to a fixed release. 6.2 6.2.1, 6.2.3 6.2.2 6.3 6.3.1 6.3.2, 6.3.3 6.4 Not Not vulnerable. vulnerable. 6.5 6.5.2, Migrate to a fixed release. 6.5.3 6.6 All Migrate to a fixed release. Fixed in 6.7.4 for ip sla responder 6.7 All configurations. ip sla responder twamp configurations are vulnerable; migrate to a fixed release. 7.0 All Migrate to a fixed release. 7.1 All Migrate to a fixed release. 7.2 All 7.2.2 7.3 and Not Not affected. later affected. Cisco has released the following SMUs to address this vulnerability. Customers who require SMUs for platforms or releases that are not listed are advised to contact their support organization. The SMUs in the following table address Cisco Bug ID CSCvw32825 (for ip sla responder configurations). Cisco IOS XR Software Release Platform SMU Name 6.4.2 ASR9K-X64 asr9k-x64-6.4.2.CSCvw32825 ASR9K-PX asr9k-px-6.6.3.CSCvw32825 6.6.3 ASR9K-X64 asr9k-x64-6.6.3.CSCvw32825 NCS5500 ncs5500-6.6.3.CSCvw32825 NCS540 ncs540-7.1.2.CSCvw32825 7.1.2 NCS560 ncs560-7.1.2.CSCvw32825 NCS5500 ncs5500-7.1.2.CSCvw32825 7.1.3 ASR9K-X64 asr9k-x64-7.1.3.CSCvw32825 The SMUs in the following table address Cisco Bug ID CSCvw61840 (for ip sla responder twamp configurations). Cisco IOS XR Software Release Platform SMU Name 6.5.3 NCS5500 ncs5500-6.5.3.CSCvw61840 6.6.3 ASR9K-PX asr9k-px-6.6.3.CSCvw61840 ASR9K-PX asr9k-x64-6.6.3.CSCvw61840 7.1.3 ASR9K-X64 asr9k-x64-7.1.3.CSCvw61840 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. Related to This Advisory o Cisco Event Response: September 2021 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ipsla-ZA3SRrpP Revision History o +---------+------------------------+---------------+--------+-------------+ | Version | Description | Section | Status | Date | +---------+------------------------+---------------+--------+-------------+ | 1.1 | Added additional SMUs. | Fixed | Final | 2021-SEP-15 | | | | Software | | | +---------+------------------------+---------------+--------+-------------+ | 1.0 | Initial public | - | Final | 2021-SEP-08 | | | release. | | | | +---------+------------------------+---------------+--------+-------------+ - -------------------------------------------------------------------------------- Cisco IOS XR Software Unauthorized Information Disclosure Vulnerability Priority: Medium Advisory ID: cisco-sa-iosxr-infodisc-CjLdGMc5 First Published: 2021 September 8 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvy33646 CVE Names: CVE-2021-34771 CWEs: CWE-201 Summary o A vulnerability in the Cisco IOS XR Software CLI could allow an authenticated, local attacker to view more information than their privileges allow. This vulnerability is due to insufficient application of restrictions during the execution of a specific command. An attacker could exploit this vulnerability by running a specific command. A successful exploit could allow the attacker to view sensitive configuration information that their privileges might not otherwise allow them to access. 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-iosxr-infodisc-CjLdGMc5 This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication . Affected Products o Vulnerable Products At the time of publication, this vulnerability affected Cisco IOS XR Software releases earlier than Release 7.3.2. 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 the following Cisco products: IOS Software IOS XE Software NX-OS 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 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, the following Cisco IOS XR Software releases contained the fix for this vulnerability: 7.3.2 and later 7.4.1 and later See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information, including SMU availability. 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. Related to This Advisory o Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-infodisc-CjLdGMc5 Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2021-SEP-08 | +----------+---------------------------+----------+--------+--------------+ - -------------------------------------------------------------------------------- Cisco IOS XR Software for ASR 9000 Series Routers Denial of Service Vulnerability Priority: High Advisory ID: cisco-sa-npspin-QYpwdhFD First Published: 2021 September 8 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvq33187 CVE Names: CVE-2021-34713 CWEs: CWE-399 Summary o A vulnerability in the Layer 2 punt code of Cisco IOS XR Software running on Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, adjacent attacker to cause the affected line card to reboot. This vulnerability is due to incorrect handling of specific Ethernet frames that cause a spin loop that can make the network processors unresponsive. An attacker could exploit this vulnerability by sending specific types of Ethernet frames on the segment where the affected line cards are attached. A successful exploit could allow the attacker to cause the affected line card to reboot. 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-npspin-QYpwdhFD This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication . Affected Products o Vulnerable Products This vulnerability affects Cisco IOS XR Software when all the following conditions apply: The Cisco IOS XR Software release is Release 6.4.0 or later but earlier than a first fixed release. The software is running on Cisco ASR 9000 Series Aggregation Services Routers. These routers have either a Typhoon or Tomahawk Ethernet line card installed. To determine which line cards are installed in the device, use the show platform command at the CLI. The following line cards are Typhoon based: A9K-1X100GE-SE A9K-1X100GE-TR A9K-24X10GE-SE A9K-24X10GE-TR A9K-2X100GE-SE A9K-2X100GE-TR A9K-36X10GE-SE A9K-36X10GE-TR A9K-40GE-SE A9K-40GE-TR A9K-4T16GE-SE A9K-4T16GE-TR A9K-MOD160-SE A9K-MOD160-TR A9K-MOD80-SE A9K-MOD80-TR Note: Cisco ASR 9001 and ASR 9001-S Routers have Typhoon-based line cards built into the standalone chassis. The following line cards are Tomahawk based: A99-12X100GE A99-12X100GE-CM A99-48X10GE-1G-SE A99-48X10GE-1G-TR A99-8X100GE-CM A99-8X100GE-SE A99-8X100GE-TR A9K-24X10GE-1G-CM A9K-24X10GE-1G-SE A9K-24X10GE-1G-TR A9K-400G-DWDM-TR A9K-48X10GE-1G-CM A9K-48X10GE-1G-SE A9K-48X10GE-1G-TR A9K-4X100GE A9K-4X100GE-SE A9K-4X100GE-TR A9K-8X100GE-CM A9K-8X100GE-SE A9K-8X100GE-TR A9K-8X100G-LB-SE A9K-8X100G-LB-TR A9K-MOD200-SE A9K-MOD200-TR A9K-MOD400-CM A9K-MOD400-SE A9K-MOD400-TR For additional information about line card type identification, see ASR 9000 Series Line Card Types . 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: IOS Software IOS XE Software IOS XRv 9000 Routers NX-OS Software 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 In the following table(s), the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability described in this advisory and the first release that includes the fix for this vulnerability. Customers are advised to upgrade to an appropriate fixed software release as indicated in this section. Cisco IOS XR Software Release First Fixed Release for This Vulnerability Earlier than 6.4 Not vulnerable. 6.4 Vulnerable; migrate to a fixed release. 6.5 Vulnerable; migrate to a fixed release. 6.6 6.6.3 6.7 6.7.1 7.0 7.0.2 7.1 7.1.1 7.2 and later Not affected. Cisco has released the following SMUs to address this vulnerability. Customers who require SMUs for platforms or releases that are not listed are advised to contact their support organization. Cisco IOS XR Software Release Platform SMU Name 6.4.2 ASR9K-X64 asr9k-x64-6.4.2.CSCvq33187 6.5.3 ASR9K-X64 asr9k-x64-6.5.3.CSCvq33187 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. Related to This Advisory o Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-npspin-QYpwdhFD Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2021-SEP-08 | +----------+---------------------------+----------+--------+--------------+ - -------------------------------------------------------------------------------- Cisco IOS XR Software for Cisco 8000 and Network Convergence System 540 Series Routers Image Verification Vulnerabilities Priority: Medium Advisory ID: cisco-sa-lnt-QN9mCzwn First Published: 2021 September 8 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvx38902 CSCvx53064 CVE Names: CVE-2021-34708 CVE-2021-34709 CWEs: CWE-347 Summary o Multiple vulnerabilities in image verification checks of Cisco Network Convergence System (NCS) 540 Series Routers, only when running Cisco IOS XR NCS540L software images, and Cisco IOS XR Software for Cisco 8000 Series Routers could allow an authenticated, local attacker to execute arbitrary code on the underlying operating system. For more information about these vulnerabilities, see the Details section of this advisory. Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lnt-QN9mCzwn This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication . Affected Products o Vulnerable Products At the time of publication, these vulnerabilities affected the following Cisco devices if they were running a vulnerable release of Cisco IOS XR Software: 8000 Series Routers NCS 540 Series Routers that are running the NCS540L images For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information. Determine the Software Version To determine whether the device is running a NCS540L software image, use the show version command in the device CLI. If the output indicates LNT, as shown in the following example, then the device is affected by these vulnerabilities: Router#show version Cisco IOS XR Software, Version 7.0.1 LNT Copyright (c) 2013-2019 by Cisco Systems, Inc.Build Information: Products Confirmed Not Vulnerable Only products listed in the Vulnerable Products section of this advisory are known to be affected by these vulnerabilities. Cisco has confirmed that these vulnerabilities do not affect the following Cisco products: IOS Software IOS XE Software NX-OS Software Details o The vulnerabilities are not dependent on one another. Exploitation of one of the vulnerabilities is not required to exploit the other vulnerability. In addition, a software release that is affected by one of the vulnerabilities may not be affected by the other vulnerability. Details about the vulnerabilities are as follows: CVE-2021-34708: Cisco IOS XR Software for Cisco 8000 and Network Convergence System 540 Series Routers Image Verification Vulnerability A vulnerability in image verification checks of Cisco NCS 540 Series Routers, only when running Cisco IOS XR NCS540L software images, and Cisco IOS XR Software for Cisco 8000 Series Routers could allow an authenticated, local attacker to execute arbitrary code on the underlying operating system. This vulnerability is due to an unsigned script within the ISO that is not verified when the install request is being processed. An attacker could exploit this vulnerability by modifying an ISO image and then either installing that image as an administrator or placing that image on a file server, which an unsuspecting administrator could then use when upgrading the device. A successful exploit could allow the attacker to execute arbitrary code on the affected device. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. Bug ID(s): CSCvx38902 CVE ID: CVE-2021-34708 Security Impact Rating (SIR): Medium CVSS Base Score: 6.0 CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N CVE-2021-34709: Cisco IOS XR Software for Cisco 8000 and Network Convergence System 540 Series Routers Image Verification Vulnerability A vulnerability in image verification checks of Cisco NCS 540 Series Routers, only when running Cisco IOS XR NCS540L software images, and Cisco IOS XR Software for Cisco 8000 Series Routers could allow an authenticated, local attacker to execute arbitrary code on the underlying operating system. This vulnerability is due to a race condition that occurs when the install request is being processed, which may allow another authenticated administrator to alter the certificate used to validate whether the installation image has a certificate that is not issued by Cisco. An attacker could exploit this vulnerability by modifying an ISO image and then either installing that image as an administrator or placing that image on a file server, which an unsuspecting administrator could then use when upgrading the device. A successful exploit could allow the attacker to execute arbitrary code on the affected device. Note: During the installation process, the attacker would need to beat the race condition to change the validated certificate. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. Bug ID(s): CSCvx53064 CVE ID: CVE-2021-34709 Security Impact Rating (SIR): Medium CVSS Base Score: 6.0 CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N Workarounds o There are no workarounds that address these vulnerabilities. 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 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, the release information in the following table (s) was accurate. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information, including SMU availability. Affected Devices First Fixed Release for These Vulnerabilities Cisco 8000 Series Routers 7.3.15 7.3.2 Cisco NCS 540 Series Routers 7.3.2 7.4.1 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 vulnerabilities that are described in this advisory. Source o These vulnerabilities were 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. Related to This Advisory o Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lnt-QN9mCzwn Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2021-SEP-08 | +----------+---------------------------+----------+--------+--------------+ - --------------------------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. 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