The Cisco perimeter switch must be configured to have Link Layer Discovery Protocol (LLDP) disabled on all external interfaces.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| low | V-221096 | SRG-NET-000364-RTR-000111 | CISC-RT-000360 | SV-221096r999705_rule | 2024-12-20 | 3 |
| Description |
|---|
| LLDP is a neighbor discovery protocol used to advertise device capabilities, configuration information, and device identity. LLDP 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 LLDP 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 LLDP is not enabled globally via the command feature lldp. By default the LLDP feature is not enabled. If LLDP is enabled, proceed to Step 2. Step 2: Verify LLDP is not enabled on any external interface as shown in the example below: interface Ethernet2/2 description link to DISN no switchport no lldp transmit Note: LLDP is enabled by default on all interfaces once it is enabled globally; hence the command lldp transmit will not be visible on the interface configuration. If LLDP transmit is enabled on any external interface, this is a finding. |
| ✔️ Fix |
|---|
| Disable LLDP transmit on all external interfaces as shown in the example below: SW2(config)# int e2/2 SW2(config-if)# no lldp transmit SW2(config-if)# end |