GEN007900 - The system must use an appropriate reverse-path filter for IPv6 network traffic, if the system uses IPv6.

Information

Reverse-path filtering provides protection against spoofed source addresses by causing the system to discard packets that have source addresses for which the system has no route or if the route does not point towards the interface on which the packet arrived. Depending on the role of the system, reverse-path filtering may cause legitimate traffic to be discarded and, therefore, should be used with a more permissive mode or filter, or not at all. Whenever possible, reverse-path filtering should be used.

Solution

Configure the system to use reverse-path filtering using IP Sec filters.

Add rules to block traffic with loopback network source addresses from being received on interfaces other than the loopback, such as other ethernet interfaces.

Use smitty or genfilt command to block loopback address from network interfaces.
# smitty ipsec6
# genfilt -v6 -a D -s <source address> -m <source netmask> -d <destination address> -M <Destination mask> -c all -o any -O any -p 0 -P 0 -w I -l y -a en0

If the system is multihomed and the attached networks are isolated or perform symmetric routing, add rules to block traffic with source addresses expected on one interface when received on another interface.

# smitty ipsec6

See Also

https://iasecontent.disa.mil/stigs/zip/U_AIX_6-1_V1R14_STIG.zip

Item Details

Category: ACCESS CONTROL

References: 800-53|AC-4, CAT|II, CCI|CCI-001551, Group-ID|V-22552, Rule-ID|SV-38964r1_rule, STIG-ID|GEN007900, Vuln-ID|V-22552

Plugin: Unix

Control ID: 93f312e55edbaebe09c342eb65939c2c19e0826bdb0cec5d97961f33588a5523