The NSX-T Tier-0 Gateway must be configured to use its loopback address as the source address for iBGP peering sessions.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-251757	T0RT-3X-000084	SV-251757r810155_rule		Low

Description
Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of the BGP routers. It is easier to construct appropriate ingress filters for router management plane traffic destined to the network management subnet since the source addresses will be from the range used for loopback interfaces instead of a larger range of addresses used for physical interfaces. Log information recorded by authentication and syslog servers will record the router’s loopback address instead of the numerous physical interface addresses. When the loopback address is used as the source for eBGP peering, the BGP session will be harder to hijack since the source address to be used is not known globally—making it more difficult for a hacker to spoof an eBGP neighbor. By using traceroute, a hacker can easily determine the addresses for an eBGP speaker when the IP address of an external interface is used as the source address. The routers within the iBGP domain should also use loopback addresses as the source address when establishing BGP sessions.

Description

Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of the BGP routers. It is easier to construct appropriate ingress filters for router management plane traffic destined to the network management subnet since the source addresses will be from the range used for loopback interfaces instead of a larger range of addresses used for physical interfaces. Log information recorded by authentication and syslog servers will record the router’s loopback address instead of the numerous physical interface addresses. When the loopback address is used as the source for eBGP peering, the BGP session will be harder to hijack since the source address to be used is not known globally—making it more difficult for a hacker to spoof an eBGP neighbor. By using traceroute, a hacker can easily determine the addresses for an eBGP speaker when the IP address of an external interface is used as the source address. The routers within the iBGP domain should also use loopback addresses as the source address when establishing BGP sessions.

STIG	Date
VMware NSX-T Tier-0 Gateway RTR Security Technical Implementation Guide	2022-09-01

Details

Check Text ( C-55194r810153_chk )
If the Tier-0 Gateway is not using iBGP, this is Not Applicable. From the NSX-T Manager web interface, go to Networking >> Tier-0 Gateways. For every Tier-0 Gateway with BGP enabled, expand the Tier-0 Gateway. Expand BGP, click on the number next to BGP Neighbors, then view the source address for each neighbor. If the Source Address is not configured as the NSX-T Tier-0 Gateway loopback address for the iBGP session, this is a finding.

Check Text ( C-55194r810153_chk )

If the Tier-0 Gateway is not using iBGP, this is Not Applicable.

From the NSX-T Manager web interface, go to Networking >> Tier-0 Gateways.

For every Tier-0 Gateway with BGP enabled, expand the Tier-0 Gateway.

Expand BGP, click on the number next to BGP Neighbors, then view the source address for each neighbor.

If the Source Address is not configured as the NSX-T Tier-0 Gateway loopback address for the iBGP session, this is a finding.

Fix Text (F-55148r810154_fix)
To configure a loopback interface do the following: From the NSX-T Manager web interface, go to Networking >> Tier-0 Gateways and expand the target Tier-0 gateway. Expand interfaces and click "Add Interface". Enter a name, select "Loopback" as the Type, enter an IP address, select an Edge Node for the interface, and then click "Save". Note: More than one loopback may need to be configured depending on the routing architecture. To set the source address for BGP neighbors do the following: From the NSX-T Manager web interface, go to Networking >> Tier-0 Gateways >> expand the target Tier-0 gateway. Expand BGP >> next to BGP Neighbors click on the number present to open the dialog >> select Edit on the target BGP Neighbor. Under Source Addresses configure the source address with the loopback address and click Save.

Fix Text (F-55148r810154_fix)

To configure a loopback interface do the following:

From the NSX-T Manager web interface, go to Networking >> Tier-0 Gateways and expand the target Tier-0 gateway.

Expand interfaces and click "Add Interface".

Enter a name, select "Loopback" as the Type, enter an IP address, select an Edge Node for the interface, and then click "Save".

Note: More than one loopback may need to be configured depending on the routing architecture.

To set the source address for BGP neighbors do the following:

From the NSX-T Manager web interface, go to Networking >> Tier-0 Gateways >> expand the target Tier-0 gateway.

Expand BGP >> next to BGP Neighbors click on the number present to open the dialog >> select Edit on the target BGP Neighbor.

Under Source Addresses configure the source address with the loopback address and click Save.