R3303-HP HSR6800 Routers Security Configuration Guide

Configuring ND attack defense

Overview

The IPv6 Neighbor Discovery (ND) protocol provides rich functions, such as address resolution, neighbor

reachability detection, duplicate address detection, router/prefix discovery and address

autoconfiguration, and redirection. However, it does not provide any security mechanisms. Attackers can

easily exploit the ND protocol to attack hosts and gateways by sending forged packets.

The ND protocol implements its function by using five types of ICMPv6 messages:

• Neighbor Solicitation (NS)

• Neighbor Advertisement (NA)

• Router Solicitation (RS)

• Router Advertisement (RA)

• Redirect (RR)

An attacker can attack a network by sending forged ICMPv6 messages, as shown in Figure 145:

• S

ending forged NS/NA/RS packets with the IPv6 address of a victim host. The gateway and other

hosts update the ND entry for the victim host with incorrect address information. As a result, all

packets intended for the victim host are sent to the attacking host.

• Sending forged RA packets with the IPv6 address of a victim gateway. As a result, all hosts attached

to the victim gateway maintain incorrect IPv6 configuration parameters and ND entries.

Figure 145 ND attack diagram

All forged ND packets have two common features:

• The Ethernet frame header and the source link layer address option of the ND packet contain

different source MAC addresses.