Cisco Small Business Smart and Managed Switches: Improper Access Control
CVE-2024-20263 is a high-severity improper access control vulnerability in Cisco Small Business Smart and Managed Switches from Cisco, with a CVSS 3.1 base score of 7.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Cisco Small Business Smart and Managed Switches versions: 2.0.0.73; 2.1.0.63; 2.2.0.63, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.45% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Cbs250-8t-d Firmware to 3.4.0.17 or 2.5.9.54, whichever matches your release line, or a later version.
- Update Cbs250-8pp-d Firmware to 3.4.0.17 or 2.5.9.54, whichever matches your release line, or a later version.
- Update Cbs250-8t-e-2g Firmware to 3.4.0.17 or 2.5.9.54, whichever matches your release line, or a later version.
- Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco Small Business Smart and Managed Switches | 2.0.0.73; 2.1.0.63; 2.2.0.63; 2.2.0.66; 2.2.5.68; 2.2.7.07; 2.2.8.04; 2.3.0.130; and 26 more ranges | Not stated |
| Cisco | Cbs250-8t-d Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-8pp-d Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-8t-e-2g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-8pp-e-2g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-8p-e-2g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-8fp-e-2g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-16t-2g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 through 2.5.9.54 | 3.4.0.17 |
| Cisco | Cbs250-16p-2g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-24t-4g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-24pp-4g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-24p-4g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-24fp-4g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-48t-4g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-48pp-4g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-48p-4g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-24t-4x Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-24p-4x Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-24fp-4x Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-48t-4x Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs250-48p-4x Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs350-8t-e-2g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs350-8p-2g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs350-8p-e-2g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
| Cisco | Cbs350-8fp-2g Firmware | 3.4 up to, but not including, 3.4.0.17; 2.5 up to, but not including, 2.5.9.54 | 3.4.0.17, 2.5.9.54 |
Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 5.8 | Medium | CNA (cisco.com) |
| CVSS 3.1 | 7.2 | High | NVD |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Access Control
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
How developers prevent this class of flaw
- Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
- Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Cisco Small Business Smart and Managed Switches
- 7.7 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Improper Access Control vulnerabilities
- 8.2 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.4 High severity
- 7.5 High severity
- 7.4 High severity
Spotted an error? Tell us.