The Juniper multicast Rendezvous Point (RP) router must be configured to filter Protocol Independent Multicast (PIM) Join messages received from the Designated Juniper router (DR) for any undesirable multicast groups.

From Juniper Router RTR Security Technical Implementation Guide

Part of SRG-NET-000019-RTR-000014

Associated with: CCI-001414

JUNI-RT-000830_rule The Juniper multicast Rendezvous Point (RP) router must be configured to filter Protocol Independent Multicast (PIM) Join messages received from the Designated Juniper router (DR) for any undesirable multicast groups.

Vulnerability discussion

Real-time multicast traffic can entail multiple large flows of data. An attacker can flood a network segment with multicast packets, over-using the available bandwidth and thereby creating a denial-of-service (DoS) condition. Hence, it is imperative that join messages are only accepted for authorized multicast groups.

Check content

Review the RP router configuration to determine if it filters PIM join messages for any reserved multicast groups. Verify that a PIM import statement has been configured as shown in the example below. protocols { … … … } pim { import MULTICAST_JOIN_POLICY; Verify that the join policy has defined both bad multicast groups and sources as shown in the example below. policy-options { … … … } policy-statement MULTICAST_JOIN_POLICY { term BAD_SOURCES { from { source-address-filter x.x.x.x/32 exact; source-address-filter x.x.x.x/24 orlonger; } then reject; } term BAD_GROUPS { from { route-filter 224.1.1.0/24 orlonger; route-filter 225.1.2.3/32 exact; route-filter 239.0.0.0/8 orlonger; … … … route-filter 232.0.0.0/8 orlonger; } then reject; } term ALLOW_OTHER { then accept; } } If the RP router peering with PIM-SM routers is not configured with a PIM import policy to block join messages for any undesirable multicast groups and sources, this is a finding.

Fix text

RP routers that are peering with customer PIM-SM routers must implement a PIM import policy to block join messages for any undesirable multicast groups and sources. Configure a multicast join policy to filter bad groups and sources as shown in the example below. [edit policy-options policy-statement MULTICAST_JOIN_POLICY] set term BAD_SOURCES from source-address-filter x.x.x.x/32 exact set term BAD_SOURCES from source-address-filter x.x.x.x/24 orlonger set term BAD_GROUPS from route-filter 224.1.1.0/24 orlonger set term BAD_GROUPS from route-filter 225.1.2.3/32 exact set term BAD_GROUPS from route-filter 239.0.0.0/8 orlonger set term BAD_GROUPS then reject set term ALLOW_OTHER then accept Configure PIM to enable the join policy as shown in the example below. [edit protocols pim] set import MULTICAST_JOIN_POLICY

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