A vulnerability in the CLI console login authentication of Cisco Nexus 9300-FX3 Series Fabric Extender (FEX) when used in UCS Fabric Interconnect deployments could allow an unauthenticated attacker with physical access to bypass authentication. This vulnerability is due to the improper implementation of the password validation function. An attacker could exploit this vulnerability by logging in to the console port on an affected device. A successful exploit could allow the attacker to bypass authentication and execute a limited set of commands local to the FEX, which could cause a device reboot and denial of service (DoS) condition. 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://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-elyfex-dos-gfvcByx This advisory is part of the February 2023 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: February 2023 Semiannual Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.
A vulnerability in the CLI console login authentication of Cisco Nexus 9300-FX3 Series Fabric Extender (FEX) when used in UCS Fabric Interconnect deployments could allow an unauthenticated attacker with physical access to bypass authentication.
This vulnerability is due to the improper implementation of the password validation function. An attacker could exploit this vulnerability by logging in to the console port on an affected device. A successful exploit could allow the attacker to bypass authentication and execute a limited set of commands local to the FEX, which could cause a device reboot and denial of service (DoS) condition.
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://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-elyfex-dos-gfvcByx
This advisory is part of the February 2023 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: February 2023 Semiannual Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.
This vulnerability affects Cisco Nexus 9300-FX3 Series FEX when used with the following Cisco products if they are running a vulnerable release of Cisco UCS Software:
Only the following Cisco Nexus 9000 Series PIDs when configured in FEX mode are vulnerable:
Note: These PIDs are not vulnerable if they are used in FEX mode with a Cisco Nexus 9000 parent switch or if they are configured as a standalone Top of Rack (TOR) switch.
For information about which Cisco software releases were vulnerable at the time of publication, 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.
To verify the FEX PID in Intersight Management Mode (IMM), use the show fex command as shown in the following example:
IMM:
6500-FI# show fex
FEX 23:
Name: FEX0023
Model: N9K-C93180YC-FX3
Serial: FDO250.....
State: Online
To verify the FEX PID in UCSM Management Mode (UMM), use the show fex detail | grep PID command in the CLI as shown in the following example:
UMM:
6400-FI# show fex detail | grep PID
PID: N9K-C93180YC-FX3
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:
There are no workarounds that address 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.
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.
The left column lists Cisco software releases, and the right column indicates whether a release was affected by the vulnerability described in this advisory and which release included the fix for this vulnerability.
| Cisco UCS Software Release | First Fixed Release for This Vulnerability |
|---|---|
| 4.0 | Not vulnerable1 |
| 4.1 | Not vulnerable1 |
| 4.2 | 4.2(2d) |
The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
This vulnerability was found during internal security testing.
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.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.0 | Initial public release. | - | Final | 2023-FEB-22 |
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