Title

The Juniper perimeter router must be configured to block all packets with any IP options. (Cat II impact)

Discussion

Packets with IP options are not fast switched and must be punted to the route engine (RE). Hackers who initiate denial-of-service (DoS) attacks on routers commonly send large streams of packets with IP options. Dropping the packets with IP options reduces the load of IP options packets on the router. The end result is a reduction in the effects of the DoS attack on the router and on downstream routers.

Check Content

This requirement is not applicable for the DODIN Backbone. Review the router configuration to determine if it will block all packets with IP options. [edit firewall family inet] filter <name> { term 1 { from { ip-options any; } then { log; syslog; discard; } } <additional accept terms> term default { then { log; syslog; discard; } } } [edit interfaces] <interface name> { unit <number> { family inet { filter input <filter name>; address <IPv4 address>/<mask>; } } } 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 to drop all packets with IP options, this is a finding.

Fix Text

This requirement is not applicable for the DODIN Backbone. Configure the router to drop all packets with IP options. set firewall family inet filter <filter name> term 1 from ip-options any set firewall family inet filter <filter name> term 1 then log set firewall family inet filter <filter name> term 1 then syslog set firewall family inet filter <filter name> term 1 then discard <additional accept terms> set firewall family inet filter default term 1 then log set firewall family inet filter default term 1 then syslog set firewall family inet filter default term 1 then discard set interfaces <interface name> unit <number> family inet filter input <filter name> set interfaces <interface name> unit <number> family inet address <IPv4 address>/<mask>

Additional Identifiers

Rule ID: SV-254023r844102_rule

Vulnerability ID: V-254023

Group Title: SRG-NET-000205-RTR-000015

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.