Check: CISC-RT-000360
Cisco NX OS Switch RTR STIG:
CISC-RT-000360
(in versions v2 r3 through v1 r1)
Title
The Cisco perimeter switch must be configured to have Link Layer Discovery Protocol (LLDP) disabled on all external interfaces. (Cat III impact)
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.
Check Content
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 Text
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
Additional Identifiers
Rule ID: SV-221096r856650_rule
Vulnerability ID: V-221096
Group Title: SRG-NET-000364-RTR-000111
Expert Comments
CCIs
Number | Definition |
---|---|
CCI-002403 |
The information system only allows incoming communications from organization-defined authorized sources routed to organization-defined authorized destinations. |
Controls
Number | Title |
---|---|
SC-7 (11) |
Restrict Incoming Communications Traffic |