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V-101655

The Cisco perimeter switch must be configured to have Link Layer Discovery Protocol (LLDP) disabled on all external interfaces.

Finding ID
CISC-RT-000360
Rule ID
SV-110759r1_rule
Severity
Cat III
CCE
(None)
Group Title
SRG-NET-000364-RTR-000111
CCI
CCI-002403
Target Key
(None)
Documentable
No
Discussion

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.

Fix Text

Disable LLDP transmit on all external interfaces as shown in the example below: SW1(config)#int g0/1 SW1(config-if)#no lldp transmit

Check Content

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.