Cisco Small Business Series Switches Stacked Reload ACL Bypass Vulnerability
cisco-sa-sb-bus-acl-bypass-5zn9hNJk · Medium · Published · Updated
A vulnerability with the access control list (ACL) management within a stacked switch configuration of Cisco Business 250 Series Smart Switches and Business 350 Series Managed Switches could allow an unauthenticated, remote attacker to bypass protection offered by a configured ACL on an affected device. This vulnerability is due to incorrect processing of ACLs on a stacked configuration when either the primary or backup switches experience a full stack reload or power cycle. An attacker could exploit this vulnerability by sending crafted traffic through an affected device. A successful exploit could allow the attacker to bypass configured ACLs, causing traffic to be dropped or forwarded in an unexpected manner. The attacker does not have control over the conditions that result in the device being in the vulnerable state. Note: In the vulnerable state, the ACL would be correctly applied on the primary devices but could be incorrectly applied to the backup devices. 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-sb-bus-acl-bypass-5zn9hNJk
Workarounds
There are no workarounds that address this vulnerability.
This vulnerability can leave the ACL configuration in an undefined state on the switch. As a mitigation, unbind the ACL from the non-working VLANs and then bind the ACL again. This is not a permanent mitigation. It would need to be reapplied if any switch stack member reloads or is power cycled.
For the specific steps for unbinding and rebinding non-working ACLs, see the Cisco Business Switches 350 Series CLI Guide https://www.cisco.com/c/en/us/td/docs/switches/lan/csbms/CBS_250_350/CLI/cbs-350-cli-.pdf (pages 105 to 107) and the Cisco Business 350 Series Switches Administration Guide https://www.cisco.com/c/en/us/td/docs/switches/lan/csbms/CBS_250_350/Administration-Guide/cbs-350.pdf (pages 325 to 326). Contact the Cisco Technical Assistance Center (TAC) if further guidance is needed.
While this mitigation has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.
| CVEs | CVE-2024-20263 |
|---|---|
| Cisco Bug IDs | CSCwf48882, CSCwh68993 |
| CVSS Score | Base 5.8 Base 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N/E:X/RL:X/RC:X |
| Product Names From Source | Cisco Small Business Smart and Managed Switches |
Related Products
| Product | CVE | Evidence |
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