Unicast Reverse Path Forwarding (uRPF) must be enabled on the NSX-T Tier-0 Gateway.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-251750	T0RT-3X-000051	SV-251750r810134_rule		High

Description
A compromised host in an enclave can be used by a malicious platform to launch cyber attacks on third parties. This is a common practice in "botnets", which are a collection of compromised computers using malware to attack other computers or networks. Distributed denial-of-service (DDoS) attacks frequently leverage IP source address spoofing to send packets to multiple hosts that in turn will then send return traffic to the hosts with the IP addresses that were forged. This can generate significant amounts of traffic. Therefore, protection measures to counteract IP source address spoofing must be taken. When uRPF is enabled in strict mode, the packet must be received on the interface that the device would use to forward the return packet; thereby mitigating IP source address spoofing.

Description

A compromised host in an enclave can be used by a malicious platform to launch cyber attacks on third parties. This is a common practice in "botnets", which are a collection of compromised computers using malware to attack other computers or networks. Distributed denial-of-service (DDoS) attacks frequently leverage IP source address spoofing to send packets to multiple hosts that in turn will then send return traffic to the hosts with the IP addresses that were forged. This can generate significant amounts of traffic. Therefore, protection measures to counteract IP source address spoofing must be taken. When uRPF is enabled in strict mode, the packet must be received on the interface that the device would use to forward the return packet; thereby mitigating IP source address spoofing.

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

Details

Check Text ( C-55187r810132_chk )
From the NSX-T Manager web interface, go to Networking >> Tier-0 Gateways. For every Tier-0 Gateway, expand Tier-0 Gateway >> Interfaces, and then click on the number of interfaces present to open the interfaces dialog. Expand each interface to view the URPF Mode configuration. If URPF Mode is not set to "Strict" on any interface, this is a finding.

Fix Text (F-55141r810133_fix)
Enable strict URPF mode on interfaces by doing the following: From the NSX-T Manager web interface, go to Networking >> Tier-0 Gateways and expand the target Tier-0 gateway. Expand Interfaces, then click on the number of interfaces present to open the interfaces dialog. Select "Edit" on the target interface. From the drop-down, set the URPF mode to "Strict" and then click "Save".