The Juniper router must be configured to have Internet Control Message Protocol (ICMP) mask reply messages disabled on all external interfaces.
An XCCDF Rule
Description
The ICMP supports IP traffic by relaying information about paths, routes, and network conditions. Routers automatically send ICMP messages under a wide variety of conditions. Mask Reply ICMP messages are commonly used by attackers for network mapping and diagnosis.
- ID
- SV-217023r855891_rule
- Version
- JUNI-RT-000180
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Configure the filter protecting the routing engine to silently drop all ICMP Mask Request messages destined to the router.
[edit firewall family inet filter DESTINED_TO_RP]
set term DENY_MASK_REQUEST from protocol icmp icmp-type mask-request
insert term DENY_MASK_REQUEST before term ALLOW_ICMP