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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2020.3296 Cisco IOS XE Software vulnerabilities 25 September 2020 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco IOS XE Software Publisher: Cisco Systems Operating System: Cisco Impact/Access: Root Compromise -- Existing Account Execute Arbitrary Code/Commands -- Existing Account Overwrite Arbitrary Files -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2020-3476 CVE-2020-3404 CVE-2020-3403 Original Bulletin: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-file-overwrite-Ynu5PrJD https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-cmdinj-2MzhjM6K https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-ctbypass-7QHAfHkK Comment: This bulletin contains three (3) Cisco Systems security advisories. - --------------------------BEGIN INCLUDED TEXT-------------------- Cisco IOS XE Software Arbitrary File Overwrite Vulnerability Priority: Medium Advisory ID: cisco-sa-file-overwrite-Ynu5PrJD First Published: 2020 September 24 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvn18213 CVE-2020-3476 CWE-552 CVSS Score: 4.4 AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N/E:X/RL:X/RC:X Summary o A vulnerability in the CLI implementation of a specific command of Cisco IOS XE Software could allow an authenticated, local attacker to overwrite arbitrary files in the underlying host file system. The vulnerability is due to insufficient validation of the parameters of a specific CLI command. An attacker could exploit this vulnerability by issuing that command with specific parameters. A successful exploit could allow the attacker to overwrite the content of any arbitrary file that resides on the underlying host file system. 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-file-overwrite-Ynu5PrJD Affected Products o Vulnerable Products At the time of publication, this vulnerability affected Cisco devices if they were running an affected version of Cisco IOS XE Software. 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 XR 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. Cisco IOS Software To help customers determine their exposure to vulnerabilities in Cisco IOS Software, Cisco provides the Cisco Software Checker to identify any Cisco Security Advisories that impact a specific Cisco IOS Software release and the earliest release that fixes the vulnerabilities described in each advisory ("First Fixed"). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities described in all the advisories identified ("Combined First Fixed"). Customers can use the Cisco Software Checker to search advisories in the following ways: Choose the software and one or more releases Upload a .txt file that includes a list of specific releases Enter the output of the show version command After initiating a search, customers can customize the search to include all Cisco Security Advisories, a specific advisory, or all advisories in the most recent bundled publication. Customers can use the following form to determine whether a release is affected by any Cisco Security Advisory by entering a Cisco IOS Software release-for example, 15.1(4)M2 : [ ] [Check] By default, the Cisco Software Checker includes results only for vulnerabilities that have a Critical or High Security Impact Rating (SIR). To include results for Medium SIR vulnerabilities, customers can use the Cisco Software Checker on Cisco.com and check the Medium check box in the drop-down list under Impact Rating when customizing a search. For a mapping of Cisco IOS XE Software releases to Cisco IOS Software releases, refer to the Cisco IOS XE 2 Release Notes , Cisco IOS XE 3S Release Notes , or Cisco IOS XE 3SG Release Notes , depending on the Cisco IOS XE Software release. Exploitation and Public Announcements o The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory. Source o This vulnerability was found during internal security testing. Cisco Security Vulnerability Policy o To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy . This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco. URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/ cisco-sa-file-overwrite-Ynu5PrJD Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2020-SEP-24 | +----------+---------------------------+----------+--------+--------------+ - -------------------------------------------------------------------------------- Cisco IOS XE Software Command Injection Vulnerability Priority: Medium Advisory ID: cisco-sa-iosxe-cmdinj-2MzhjM6K First Published: 2020 September 24 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvs07077 CVE-2020-3403 CWE-78 CVSS Score: 6.7 AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X Summary o A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker to inject a command to the underlying operating system that will execute with root privileges upon the next reboot of the device. The authenticated user must have privileged EXEC permissions on the device. The vulnerability is due to insufficient protection of values passed to a script that executes during device startup. An attacker could exploit this vulnerability by writing values to a specific file. A successful exploit could allow the attacker to execute commands with root privileges each time the affected device is restarted. 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-iosxe-cmdinj-2MzhjM6K Affected Products o Vulnerable Products At the time of publication, this vulnerability affected devices if they were running a vulnerable release of Cisco IOS XE Software. 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 XR 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. Cisco IOS and IOS XE Software To help customers determine their exposure to vulnerabilities in Cisco IOS and IOS XE Software, Cisco provides the Cisco Software Checker to identify any Cisco Security Advisories that impact a specific software release and the earliest release that fixes the vulnerabilities described in each advisory ("First Fixed"). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities described in all the advisories identified ("Combined First Fixed"). Customers can use the Cisco Software Checker to search advisories in the following ways: Choose the software and one or more releases Upload a .txt file that includes a list of specific releases Enter the output of the show version command After initiating a search, customers can customize the search to include all Cisco Security Advisories, a specific advisory, or all advisories in the most recent bundled publication. Customers can also use the following form to determine whether a release is affected by any Cisco Security Advisory by entering a Cisco IOS or IOS XE Software release-for example, 15.1(4)M2 or 3.13.8S : [ ] [Check] By default, the Cisco Software Checker includes results only for vulnerabilities that have a Critical or High Security Impact Rating (SIR). To include results for Medium SIR vulnerabilities, customers can use the Cisco Software Checker on Cisco.com and check the Medium check box in the drop-down list under Impact Rating when customizing a search. For a mapping of Cisco IOS XE Software releases to Cisco IOS Software releases, refer to the Cisco IOS XE 2 Release Notes , Cisco IOS XE 3S Release Notes , or Cisco IOS XE 3SG Release Notes , depending on the Cisco IOS XE Software release. 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 by JG of Cisco ASIG during internal security testing. Cisco Security Vulnerability Policy o To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy . This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco. URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/ cisco-sa-iosxe-cmdinj-2MzhjM6K Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2020-SEP-24 | +----------+---------------------------+----------+--------+--------------+ - -------------------------------------------------------------------------------- Cisco IOS XE Software Consent Token Bypass Vulnerability Priority: Medium Advisory ID: cisco-sa-iosxe-ctbypass-7QHAfHkK First Published: 2020 September 24 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvq91055 CVE-2020-3404 CWE-863 CVSS Score: 6.7 AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X Summary o A vulnerability in the persistent Telnet/Secure Shell (SSH) CLI of Cisco IOS XE Software could allow an authenticated, local attacker to gain shell access on an affected device and execute commands on the underlying operating system (OS) with root privileges. The vulnerability is due to insufficient enforcement of the consent token in authorizing shell access. An attacker could exploit this vulnerability by authenticating to the persistent Telnet/SSH CLI on an affected device and requesting shell access. A successful exploit could allow the attacker to gain shell access on the affected device and execute commands on the underlying OS with root privileges. 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-iosxe-ctbypass-7QHAfHkK Affected Products o Vulnerable Products At the time of publication, this vulnerability affected devices if they were running a vulnerable release of Cisco IOS XE Software and had the persistent Telnet or persistent SSH feature configured. For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory. Determine the Device Configuration To determine whether the persistent Telnet feature is enabled for a device, administrators can log in to the device and use the show running-config | include transport type persistent telnet command in the CLI to check for the presence of the transport type persistent telnet input < name > command in the global configuration. To determine whether the persistent SSH feature is enabled for a device, administrators can log in to the device and use the show running-config | include transport type persistent ssh command in the CLI to check for the presence of the transport type persistent ssh input < name > command in the global configuration. If both commands return no output or an error message, persistent Telnet and persistent SSH are not configured on the device and it is not vulnerable. 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 XR 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. Cisco IOS and IOS XE Software To help customers determine their exposure to vulnerabilities in Cisco IOS and IOS XE Software, Cisco provides the Cisco Software Checker to identify any Cisco Security Advisories that impact a specific software release and the earliest release that fixes the vulnerabilities described in each advisory ("First Fixed"). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities described in all the advisories identified ("Combined First Fixed"). Customers can use the Cisco Software Checker to search advisories in the following ways: Choose the software and one or more releases Upload a .txt file that includes a list of specific releases Enter the output of the show version command After initiating a search, customers can customize the search to include all Cisco Security Advisories, a specific advisory, or all advisories in the most recent bundled publication. Customers can also use the following form to determine whether a release is affected by any Cisco Security Advisory by entering a Cisco IOS or IOS XE Software release-for example, 15.1(4)M2 or 3.13.8S : [ ] [Check] By default, the Cisco Software Checker includes results only for vulnerabilities that have a Critical or High Security Impact Rating (SIR). To include results for Medium SIR vulnerabilities, customers can use the Cisco Software Checker on Cisco.com and check the Medium check box in the drop-down list under Impact Rating when customizing a search. For a mapping of Cisco IOS XE Software releases to Cisco IOS Software releases, refer to the Cisco IOS XE 2 Release Notes , Cisco IOS XE 3S Release Notes , or Cisco IOS XE 3SG Release Notes , depending on the Cisco IOS XE Software release. 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 by XB of Cisco ASIG during internal security testing. Cisco Security Vulnerability Policy o To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy . This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco. URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/ cisco-sa-iosxe-ctbypass-7QHAfHkK Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2020-SEP-24 | +----------+---------------------------+----------+--------+--------------+ - --------------------------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. 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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). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBX21KsuNLKJtyKPYoAQi0sA//eKOw79F/ZPB8yjqdiirs8G2Webft5Jtl uaL93ZtKM+vpzmurzg9Nid3IGNgdgnmbP42B3fA6Nu3NobrrtPcR0YEKZ1EtLv7n ffiZgcpBL4jMZfOXugH9DjPboWMrJi3dV3Hev6ego/Y+Au2hUn02ULChqyF8m/K7 yNPLfYWIHLl+7F8HjpsnTmaAEbRl63fsKRAwuqwawrNUEFeR1BW/LAnURwvHxsag exBtzugW93E3tA12q5pcVlIndZlPdIssZO8KuRiZgieUVoeUy70laKAEQPBFEjgh QjGq2Jr/wr6+eooJ5cCw1HYZOPAtFMM+gvsLFd6Y6WGmswH1SfuiNOEcOQLMze6a BojzKtkz7jWFPXHXicminTlGA3fnv7yZtyzpRDW5KZ7WmATp+f+DRygV0XupnBue OEKfokEh5z8DAMbtVg4ODTCyips6Z8YNeAPayxbC2SEH8dzvZB+96DW5afYIz+Jy t3kxqD1rE5Qboko5O9qxKgJUUCnEM2ZFNE4c5rRgCEBphVQTXs9uX4FnisyRDbxU SM35jvgiz8sE+VWBauyIOjN8D3Xv16XvQjujiyQXkyWW/hzclPzcRiqeklfqcGLa bQA+/bdxkA0k3g+6Q2fKF3dd1uGkAWbNBr6VSRNtx2McZM6egDngNPi6G/mjLORV 26PzfKV1MnU= =MGEj -----END PGP SIGNATURE-----