The NSX Tier-0 Gateway router must be configured to restrict it from accepting outbound IP packets that contain an illegitimate address in the source address field by enabling Unicast Reverse Path Forwarding (uRPF).
An XCCDF Rule
Description
<VulnDiscussion>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.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-263302r977673_rule
- Severity
- High
- References
- Updated
Remediation - Manual Procedure
Enable strict URPF mode on interfaces by doing the following:
From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-0 Gateways and expand the target Tier-0 gateway.
Expand "Interfaces and GRE Tunnels", click on the number of interfaces present to open the interfaces dialog, and then select "Edit" on the target interface.