Headline
CVE-2022-20944: Cisco Security Advisory: Cisco IOS XE Software for Catalyst 9200 Series Switches Arbitrary Code Execution Vulnerability
A vulnerability in the software image verification functionality of Cisco IOS XE Software for Cisco Catalyst 9200 Series Switches could allow an unauthenticated, physical attacker to execute unsigned code at system boot time. This vulnerability is due to an improper check in the code function that manages the verification of the digital signatures of system image files during the initial boot process. An attacker could exploit this vulnerability by loading unsigned software on an affected device. A successful exploit could allow the attacker to boot a malicious software image or execute unsigned code and bypass the image verification check part of the boot process of the affected device. To exploit this vulnerability, the attacker needs either unauthenticated physical access to the device or privileged access to the root shell on the device. Note: In Cisco IOS XE Software releases 16.11.1 and later, root shell access is protected by the Consent Token mechanism. However, an attacker with level-15 privileges could easily downgrade the Cisco IOS XE Software running on a device to a release where root shell access is more readily available.
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.htmlAdditionally, 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.
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. This tool identifies any Cisco security advisories that impact a specific software release and the earliest release that fixes the vulnerabilities that are described in each advisory (“First Fixed”). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities that are described in all the advisories that the Software Checker identifies (“Combined First Fixed”).
To use the tool, go to the Cisco Software Checker page and follow the instructions. Alternatively, use the following form to determine whether a release is affected by any Cisco Security Advisory. To use the form, follow these steps:
- Choose which advisories the tool will search-only this advisory, only advisories with a Critical or High Security Impact Rating (SIR), or all advisories.
- Enter a release number-for example, 15.9(3)M2 or 17.3.3.
- Click Check.