The Cisco perimeter router 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-216674 | SRG-NET-000364-RTR-000111 | CISC-RT-000360 | SV-216674r855821_rule | 2024-11-25 | 3 |
| Description |
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| 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 |
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| This requirement is not applicable for the DODIN Backbone. Step 1: Verify LLDP is not enabled globally via the command. lldp run By default LLDP is not enabled globally. 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 GigabitEthernet0/1 ip address x.1.12.1 255.255.255.252 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 |
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| Disable LLDP transmit on all external interfaces as shown in the example below: R5(config)#int g0/1 R5(config-if)#no lldp transmit |