Check: CISC-RT-000350
Cisco NX OS Switch RTR STIG:
CISC-RT-000350
(in versions v2 r3 through v1 r0.1)
Title
The Cisco perimeter switch must be configured to block all packets with any IP options. (Cat II impact)
Discussion
Packets with IP options are not fast switched and henceforth must be punted to the switch processor. Hackers who initiate denial-of-service (DoS) attacks on switches commonly send large streams of packets with IP options. Dropping the packets with IP options reduces the load of IP options packets on the switch. The end result is a reduction in the effects of the DoS attack on the switch and on downstream switches.
Check Content
In Cisco NX-OS, all packets with any header option other than the “source-route” header option are dropped. By default, ipv4 source routing is enabled. Verify that source routing is disabled via the following command: no ip source-route If the switch is not configured to drop all packets with IP option source routing, this is a finding.
Fix Text
Configure the switch to drop all packets with IP option source routing. SW1(config)# no ip source-route SW1(config)# end
Additional Identifiers
Rule ID: SV-221095r856656_rule
Vulnerability ID: V-221095
Group Title: SRG-NET-000205-RTR-000015
Expert Comments
CCIs
Number | Definition |
---|---|
CCI-002403 |
The information system only allows incoming communications from organization-defined authorized sources routed to organization-defined authorized destinations. |
Controls
Number | Title |
---|---|
SC-7 (11) |
Restrict Incoming Communications Traffic |