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The Juniper perimeter router must be configured to block inbound packets with source Bogon IP address prefixes.


Overview

Finding ID Version Rule ID IA Controls Severity
V-90849 JUNI-RT-000270 SV-101059r1_rule Medium
Description
Packets with Bogon IP source addresses should never be allowed to traverse the IP core. Bogon IP networks are RFC1918 addresses or address blocks that have never been assigned by the IANA or have been reserved.
STIG Date
Juniper Router RTR Security Technical Implementation Guide 2018-11-15

Details

Check Text ( C-90113r2_chk )
This requirement is not applicable for the DoDIN Backbone.

Review the router configuration to verify that an ingress filter applied to all external interfaces is blocking packets with Bogon source addresses.

Verify a prefix list has been configured containing the current Bogon prefixes as shown in the example below.

policy-options {
prefix-list BOGON_PREFIXES {
0.0.0.0/8;
10.0.0.0/8;
100.64.0.0/10;
127.0.0.0/8;
169.254.0.0/16;
172.16.0.0/12;
192.0.0.0/24;
192.0.2.0/24;
192.168.0.0/16;
198.18.0.0/15;
198.51.100.0/24;
203.0.113.0/24;
224.0.0.0/4;
240.0.0.0/4;
}
}

Verify that the inbound filter applied to all external interfaces will block all traffic from Bogon source addresses.

interfaces {
ge-0/0/0 {
unit 0 {
family inet {
filter {
input INBOUND_FILTER;
}
address 11.1.12.2/24;
}
}
}
…
…
…
firewall {
family inet {
filter INBOUND_FILTER {
term BLOCK_BOGONS {
from {
source-prefix-list {
BOGON_PREFIXES;
}
}
then {
syslog;
discard;
}
}
term ALLOW_BGP {
from {
protocol tcp;
destination-port bgp;
}
then accept;
}
term ALLOW_XYZ {
from {
protocol xyz;
}
then accept;
}
term DENY_ALL_OTHER {
then {
syslog;
reject;
}
}
}
}

If the router is not configured to block inbound packets with source Bogon IP address prefixes, this is a finding.
Fix Text (F-97157r2_fix)
This requirement is not applicable for the DoDIN Backbone.

Configure the perimeter to block inbound packets with Bogon source addresses.

Configure a prefix list containing the current Bogon prefixes as shown below.

[edit policy-options]
set prefix-list BOGON_PREFIXES 0.0.0.0/8
set prefix-list BOGON_PREFIXES 10.0.0.0/8
set prefix-list BOGON_PREFIXES 100.64.0.0/10
set prefix-list BOGON_PREFIXES 127.0.0.0/8
set prefix-list BOGON_PREFIXES 169.254.0.0/16
set prefix-list BOGON_PREFIXES 172.16.0.0/12
set prefix-list BOGON_PREFIXES 192.0.0.0/24
set prefix-list BOGON_PREFIXES 192.0.2.0/24
set prefix-list BOGON_PREFIXES 192.168.0.0/16
set prefix-list BOGON_PREFIXES 198.18.0.0/15
set prefix-list BOGON_PREFIXES 198.51.100.0/24
set prefix-list BOGON_PREFIXES 203.0.113.0/24
set prefix-list BOGON_PREFIXES 224.0.0.0/4
set prefix-list BOGON_PREFIXES 240.0.0.0/4

Add a term to the inbound filter to block the Bogon prefixes.

[edit firewall family inet filter INBOUND_FILTER]
set term BLOCK_BOGONS from source-prefix-list BOGON_PREFIXES
set term BLOCK_BOGONS then syslog discard
insert term BLOCK_BOGONS before term ALLOW_BGP