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
<VulnDiscussion>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.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-217023r855891_rule
- Severity
- Medium
- References
- Updated
Remediation - 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