STIGQter: STIG Summary: Juniper EX Series Switches Router Security Technical Implementation Guide Version: 2 Release: 1 Benchmark Date: 24 Jul 2024:

The Juniper router must be configured to drop all fragmented Internet Control Message Protocol (ICMP) packets destined to itself.

DISA Rule

SV-254011r997525_rule

Vulnerability Number

V-254011

Group Title

SRG-NET-000205-RTR-000002

Rule Version

JUEX-RT-000390

Severity

CAT II

CCI(s)

• CCI-001097 - Monitor and control communications at the external managed interfaces to the system and at key managed interfaces within the system.
• CCI-004866 - Employ organization-defined controls by type of denial-of-service to achieve the denial-of-service objective.

Weight

10

Fix Recommendation

Ensure all routers have their receive path filter configured to drop all fragmented ICMP packets.

set policy-options prefix-list router-addresses-ipv4 <interface IPv4 address>/32
set firewall family inet filter protect_re term 1 from destination-prefix-list router-addresses-ipv4
set firewall family inet filter protect_re term 1 from protocol icmp
set firewall family inet filter protect_re term 1 from is-fragment
set firewall family inet filter protect_re term 1 then log
set firewall family inet filter protect_re term 1 then syslog
set firewall family inet filter protect_re term 1 then discard
<additional terms to account for all traffic destined for the RE>

set interfaces lo0 unit 0 family inet filter input protect_re

Check Contents

Review the firewall filter for the router receive path. Firewall filters applied to the loopback interface affects traffic destined for the Route Engine (RE) regardless of ingress interface. Individual firewall filters are also supported on each ingress interface.
Note: Verify the firewall filter applied to the loopback interface addresses all traffic destined for the RE (e.g., BGP, OSPF, etc.).

Verify that it will drop all fragmented ICMP packets destined to itself. For example:
[edit policy-options]
prefix-list router-addresses-ipv4 {
<interface IPv4 address>/32;
<other router interface addresses>;
}
[edit firewall family inet]
filter protect_re {
term 1 {
from {
destination-prefix-list {
router-addresses-ipv4;
}
is-fragment;
protocol icmp;
}
then {
log;
syslog;
discard;
}
}
<additional terms for RE destined traffic>
}
[edit interfaces lo0 unit 0]
family inet {
filter {
input protect_re;
}
address <IPv4 address>/32;
}

Note: Some Juniper devices support both monolithic filters and filter lists. Filter lists separate each term, or set of terms, into a separate filter that is applied sequentially to an interface. If using filter lists, the keywords "input" or "output" change to "input-list" or "output-list". Verify the final list item is a deny-all filter. The deny-all filter is created once per family and can be reused across multiple lists. For example:

input-list [ permit_mgt permit_routing_protocols default-deny ];

If the router is not configured with a receive-path filter to drop all fragmented ICMP packets, this is a finding.

Note: If the platform does not support the receive path filter, verify that all layer 3 interfaces have an ingress filter to control what packets are allowed to be destined to the router for processing.

Vulnerability Number

V-254011

Documentable

False

Rule Version

JUEX-RT-000390

Severity Override Guidance

Review the firewall filter for the router receive path. Firewall filters applied to the loopback interface affects traffic destined for the Route Engine (RE) regardless of ingress interface. Individual firewall filters are also supported on each ingress interface.
Note: Verify the firewall filter applied to the loopback interface addresses all traffic destined for the RE (e.g., BGP, OSPF, etc.).

Verify that it will drop all fragmented ICMP packets destined to itself. For example:
[edit policy-options]
prefix-list router-addresses-ipv4 {
<interface IPv4 address>/32;
<other router interface addresses>;
}
[edit firewall family inet]
filter protect_re {
term 1 {
from {
destination-prefix-list {
router-addresses-ipv4;
}
is-fragment;
protocol icmp;
}
then {
log;
syslog;
discard;
}
}
<additional terms for RE destined traffic>
}
[edit interfaces lo0 unit 0]
family inet {
filter {
input protect_re;
}
address <IPv4 address>/32;
}

Note: Some Juniper devices support both monolithic filters and filter lists. Filter lists separate each term, or set of terms, into a separate filter that is applied sequentially to an interface. If using filter lists, the keywords "input" or "output" change to "input-list" or "output-list". Verify the final list item is a deny-all filter. The deny-all filter is created once per family and can be reused across multiple lists. For example:

input-list [ permit_mgt permit_routing_protocols default-deny ];

If the router is not configured with a receive-path filter to drop all fragmented ICMP packets, this is a finding.

Note: If the platform does not support the receive path filter, verify that all layer 3 interfaces have an ingress filter to control what packets are allowed to be destined to the router for processing.

Check Content Reference

M

Target Key

5479