The Cisco perimeter switch must be configured to have Cisco Discovery Protocol (CDP) disabled on all external interfaces.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| low | V-221097 | SRG-NET-000364-RTR-000111 | CISC-RT-000370 | SV-221097r999706_rule | 2024-12-20 | 3 |
| Description |
|---|
| CDP is a Cisco proprietary neighbor discovery protocol used to advertise device capabilities, configuration information, and device identity. CDP is media-and-protocol-independent as it runs over layer 2; therefore, two network nodes that support different layer 3 protocols can still learn about each other. Allowing CDP messages to reach external network nodes provides an attacker a method to obtain information of the network infrastructure that can be useful to plan an attack. |
| ℹ️ Check |
|---|
| Step 1: Verify CDP is not enabled globally via the command no cdp enable By default CDP is enabled globally; hence, the command cdp enable will not be shown in the configuration. If CDP is enabled, proceed to Step 2. Step 2: Verify CDP is not enabled on any external interface as shown in the example below: interface Ethernet2/2 description link to DISN no switchport no cdp enable Note: By default CDP is enabled on all interfaces if CDP is enabled globally. If CDP is enabled on any external interface, this is a finding. |
| ✔️ Fix |
|---|
| Disable CDP on all external interfaces via no cdp enable interface command or disable CDP globally via no cdp enable command. |