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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2021.1031 Cisco IOS XE ROM Monitor Software for Cisco Industrial Switches OS Command Injection Vulnerability 25 March 2021 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco IOS XE ROM Monitor Software Publisher: Cisco Systems Operating System: Cisco Impact/Access: Execute Arbitrary Code/Commands -- Console/Physical Resolution: Patch/Upgrade CVE Names: CVE-2021-1452 Original Bulletin: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-romvar-cmd-inj-N56fYbrw - --------------------------BEGIN INCLUDED TEXT-------------------- Cisco IOS XE ROM Monitor Software for Cisco Industrial Switches OS Command Injection Vulnerability Priority: High Advisory ID: cisco-sa-iosxe-romvar-cmd-inj-N56fYbrw First Published: 2021 March 24 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvu65039 CVE Names: CVE-2021-1452 CWEs: CWE-78 Summary o A vulnerability in the ROM Monitor (ROMMON) of Cisco IOS XE Software for Cisco Catalyst IE3200, IE3300, and IE3400 Rugged Series Switches, Cisco Catalyst IE3400 Heavy Duty Series Switches, and Cisco Embedded Services 3300 Series Switches could allow an unauthenticated, physical attacker to execute unsigned code at system boot time. This vulnerability is due to incorrect validations of specific function arguments passed to a boot script when specific ROMMON variables are set. An attacker could exploit this vulnerability by setting malicious values for a specific ROMMON variable. A successful exploit could allow the attacker to execute unsigned code and bypass the image verification check during the secure boot process of an affected device. To exploit this vulnerability, the attacker would need to have unauthenticated, physical access to the device or obtain privileged access to the root shell 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-iosxe-romvar-cmd-inj-N56fYbrw Affected Products o Vulnerable Products This vulnerability affects the following Cisco routers if they are running a Cisco IOS XE ROMMON Software release earlier than Release 7.0: Catalyst IE3200 Rugged Series Switches Catalyst IE3300 Rugged Series Switches Catalyst IE3400 Rugged Series Switches Catalyst IE3400 Heavy Duty Series Switches Embedded Services 3300 Series Switches (ESS 3300) Determine the Cisco IOS XE ROMMON Software Release To determine which Cisco IOS XE ROMMON Software release is running on a device, log in to the device and use the show rom-monitor rp active command in the CLI. The following example shows the output of this command for a device that is running Cisco IOS XE ROMMON Software Release 7.1.1: Switch# show rom-monitor rp active Version 7.1.1 [RELEASE SOFTWARE] 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 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 The ROMMON software is a bootstrap program that initializes the hardware and boots Cisco IOS XE Software when a device is powered on or reloaded. The ROMMON software is bundled with the Cisco IOS XE binary, which can be downloaded from the Software Center on Cisco.com. Customers are advised to upgrade to an appropriate fixed software release as indicated in the following table: Affected Cisco Devices First Fixed Cisco IOS XE First Fixed Cisco IOS ROMMON Software Release XE Software Release Catalyst IE3200 Rugged 7.0 and later 17.3.1 and later Series Switches Catalyst IE3300 Rugged 7.0 and later 17.3.1 and later Series Switches Catalyst IE3400 Rugged 7.0 and later 17.3.1 and later Series Switches Catalyst IE3400 Heavy 7.0 and later 17.3.1 and later Duty Series Switches Embedded Service 3300 7.0 and later 17.3.1 and later Series Switches ROMMON code is included as part of a Cisco IOS XE Software binary image, and it is not available as a standalone binary. Customers looking to upgrade their ROMMON to a fixed version will need to upgrade the Cisco IOS XE Software that is running on a device to Release 17.3.1 or later. On first boot, Cisco IOS XE Software will check the installed ROMMON version and upgrade it to Release 7.0 if the device is running an older version. Note: If the device is downgraded to an older Cisco IOS XE Software release, the ROMMON will be rewritten with a previous ROMMON version, which may make the device vulnerable. 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 by X.B. of Cisco. 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-romvar-cmd-inj-N56fYbrw Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2021-MAR-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. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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