The Cisco router must be configured to log all packets that have been dropped at interfaces via ACL.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-216749	CISC-RT-000200	SV-216749r531087_rule		Low

Description
Auditing and logging are key components of any security architecture. It is essential for security personnel to know what is being done or attempted to be done, and by whom, to compile an accurate risk assessment. Auditing the actions on network devices provides a means to recreate an attack or identify a configuration mistake on the device.

STIG	Date
Cisco IOS XR Router RTR Security Technical Implementation Guide	2020-09-23

Details

Check Text ( C-17981r288636_chk )

Review all ACLs used to filter traffic and verify that packets being dropped are logged as shown in the configuration 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 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 60 permit tcp any any established … … … 140 deny ipv4 any any log If packets being dropped at interfaces are not logged, this is a finding.

Fix Text (F-17979r288637_fix)
Configure ACLs to log packets that are dropped as shown in the example below. RP/0/0/CPU0:R3(config)#ipv4 access-list EXTERNAL_ACL_INBOUND … … … RP/0/0/CPU0:R3(config-ipv4-acl)#deny ip any any log