The Cisco perimeter router must be configured to have Link Layer Discovery Protocol (LLDP) disabled on all external interfaces.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-216764 | CISC-RT-000360 | SV-216764r856442_rule | CCI-002403 | low |
| 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. | ||||
| STIG | Date | |||
| Cisco IOS XR Router RTR Security Technical Implementation Guide | 2024-08-22 | |||
Details
Check Text (C-216764r856442_chk)
This requirement is not applicable for the DODIN Backbone.
Step 1: Verify LLDP is not enabled globally via the command
lldp
By default LLDP is not enabled globally. If LLDP is enabled, proceed to step 2.
Step 2: Verify LLDP transmit is disabled on any external interface as shown in the example below.
interface GigabitEthernet0/0/0/1
ipv4 address x.1.34.3 255.255.255.252
lldp
transmit disable
Note: LLDP is enabled by default on all interfaces once it is enabled globally; hence the commands lldp transmit and lldp receive will not be visible on the interface configuration.
If LLDP transmit is enabled on any external interface, this is a finding.
Fix Text (F-17994r288676_fix)
Disable LLDP transmit on all external interfaces as shown in the example below.
RP/0/0/CPU0:R3(config)#interface g0/0/0/1
RP/0/0/CPU0:R3(config-if)#lldp transmit disable