V-216750

Discussion

Without establishing where events occurred, it is impossible to establish, correlate, and investigate the events leading up to an outage or attack. In order to compile an accurate risk assessment and provide forensic analysis, it is essential for security personnel to know where events occurred such as router components, modules, device identifiers, node names, and functionality. Associating information about where the event occurred within the network provides a means of investigating an attack, recognizing resource utilization or capacity thresholds, or identifying an improperly configured router.

Check Content

Review the router configuration to verify that events are logged containing information to establish where the events occurred as shown in the example below.

ipv4 access-list EXTERNAL_ACL_INBOUND
 10 permit tcp host x.11.1.1 eq bgp host x.11.1.2
 20 permit tcp host x.11.1.1 host x.11.1.2 eq bgp
 25 deny icmp any host x.11.1.2 fragments log-input 
 30 permit icmp host x.11.1.1 host x.11.1.2 echo
 40 permit icmp host x.11.1.1 host x.11.1.2 echo-reply
 50 deny ipv4 any host x.11.1.1 log-input
 60 permit tcp any any established
 …
 …
 …
 140 deny ipv4 any any log-input

Note: When the log-input parameter is configured on deny statements, the log record will contain the interface where ingress packet has been dropped.

If the router is not configured to produce audit records containing information to establish to establish where the events occurred, this is a finding.