Headline
CVE-2023-20234: Cisco Security Advisory: Cisco FXOS Software Arbitrary File Write Vulnerability
A vulnerability in the CLI of Cisco FXOS Software could allow an authenticated, local attacker to create a file or overwrite any file on the filesystem of an affected device, including system files. The vulnerability occurs because there is no validation of parameters when a specific CLI command is used. An attacker could exploit this vulnerability by authenticating to an affected device and using the command at the CLI. A successful exploit could allow the attacker to overwrite any file on the disk of the affected device, including system files. The attacker must have valid administrative credentials on the affected device to exploit this vulnerability.
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 FXOS Software
To help customers determine their exposure to vulnerabilities in Cisco FXOS 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 search for vulnerabilities that affect a specific software release. 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.
- Choose the appropriate platform. Note: Firepower 1000 Series and 2100 Series appliances and Secure Firewall 3100 Series appliances use Cisco FXOS Software as an underlying operating system, which is included in Cisco ASA Software unified image bundles or in Cisco FTD Software unified image bundles. Select either ASA or FTD software to get results for that platform.
- Enter a release number-for example, 2.9.1.158 for Cisco Firepower 4100 Series Security Appliances.
- Click Check.