STIGQter STIGQter: STIG Summary: Cisco IOS Switch RTR Security Technical Implementation Guide Version: 2 Release: 1 Benchmark Date: 23 Apr 2021:

The Cisco switch must be configured to restrict traffic destined to itself.

DISA Rule

SV-220429r622190_rule

Vulnerability Number

V-220429

Group Title

SRG-NET-000205-RTR-000001

Rule Version

CISC-RT-000130

Severity

CAT I

CCI(s)

Weight

10

Fix Recommendation

Step 1: Configure the ACL for any external interfaces as shown in the example below:

SW1(config)#ip access-list extended EXTERNAL_ACL
SW1(config-ext-nacl)#permit icmp host x.11.1.1 host x.11.1.2 echo
SW1(config-ext-nacl)#permit icmp host x.11.1.1 host x.11.1.2 echo-reply
SW1(config-ext-nacl)#deny ip any host x.11.1.1 log-input
SW1(config-ext-nacl)#permit …
…
…
…
SW1(config-ext-nacl)#deny ip any any log-input

Step 2: Configure the ACL for any external interfaces as shown in the example below:

SW1(config)#ip access-list extended INTERNAL_ACL
SW1(config-ext-nacl)#permit ospf host 10.1.12.1 host 10.1.12.2
SW1(config-ext-nacl)#permit tcp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq 22
SW1(config-ext-nacl)#permit tcp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq tacacs
SW1(config-ext-nacl)#permit udp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq snmp
SW1(config-ext-nacl)#permit udp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq ntp
SW1(config-ext-nacl)#deny ip any host 10.1.12.2 log-input
SW1(config-ext-nacl)#permit …
…
…
…
SW1(config-ext-nacl)#permit ip any any log-input
SW1(config-ext-nacl)#exit

Note: Best practice is to configure the ACL statements relative to traffic destined to the switch first followed by ACL statements for transit traffic.

Step 3: Apply the ACLs to the appropriate interface as shown in the example below:

SW1(config)#int g0/2
SW1(config-if)#ip access-group EXTERNAL_ACL in
SW1(config)#int g0/3
SW1(config-if)#ip access-group INTERNAL_ACL in

Check Contents

Review the external and internal access control lists (ACLs) to verify that the switch is configured to only allow specific management and control plane traffic from specific sources destined to itself.

Step 1: Verify that ACLs have been configured as shown in the example below that matches expected control plane and management plane traffic. With the exception of Internet Control Message Protocol (ICMP), all other traffic destined to the switch should be dropped.

ip access-list extended EXTERNAL_ACL
permit icmp host x.11.1.1 host x.11.1.2 echo
permit icmp host x.11.1.1 host x.11.1.2 echo-reply
deny ip any host x.11.1.1 log-input
permit …
…
…
…
deny ip any any log-input

ip access-list extended INTERNAL_ACL
permit icmp any any
permit ospf host 10.1.12.1 host 10.1.12.2
permit tcp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq 22
permit tcp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq tacacs
permit udp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq snmp
permit udp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq ntp
deny ip any host 10.1.12.2 log-input
permit …
…
…
…
deny ip any any log-input

Note: For the internal ACL example, all switches within the hypothetical network (10.1.0.0/16) have been configured to use the loopback address to source all management traffic (not shown); hence, the loopbacks are the only allowable destination address for management traffic. In addition, all management traffic destined to the switch must originate from the management network (10.2.1.0/24). With the exception of link-local control plane traffic and ICMP, all other traffic destined to any physical interface address will be dropped.

Step 2: Verify that the ACL has been applied to the appropriate interface as shown in the example below:

interface GigabitEthernet0/2
no switchport
ip address x.11.1.2 255.255.255.254
ip access-group EXTERNAL_ACL in
interface GigabitEthernet0/3
no switchport
ip address 10.1.12.2 255.255.255.0
ip access-group INTERNAL_ACL in

If the switch is not configured to restrict traffic destined to itself, this is a finding.

Vulnerability Number

V-220429

Documentable

False

Rule Version

CISC-RT-000130

Severity Override Guidance

Review the external and internal access control lists (ACLs) to verify that the switch is configured to only allow specific management and control plane traffic from specific sources destined to itself.

Step 1: Verify that ACLs have been configured as shown in the example below that matches expected control plane and management plane traffic. With the exception of Internet Control Message Protocol (ICMP), all other traffic destined to the switch should be dropped.

ip access-list extended EXTERNAL_ACL
permit icmp host x.11.1.1 host x.11.1.2 echo
permit icmp host x.11.1.1 host x.11.1.2 echo-reply
deny ip any host x.11.1.1 log-input
permit …
…
…
…
deny ip any any log-input

ip access-list extended INTERNAL_ACL
permit icmp any any
permit ospf host 10.1.12.1 host 10.1.12.2
permit tcp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq 22
permit tcp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq tacacs
permit udp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq snmp
permit udp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq ntp
deny ip any host 10.1.12.2 log-input
permit …
…
…
…
deny ip any any log-input

Note: For the internal ACL example, all switches within the hypothetical network (10.1.0.0/16) have been configured to use the loopback address to source all management traffic (not shown); hence, the loopbacks are the only allowable destination address for management traffic. In addition, all management traffic destined to the switch must originate from the management network (10.2.1.0/24). With the exception of link-local control plane traffic and ICMP, all other traffic destined to any physical interface address will be dropped.

Step 2: Verify that the ACL has been applied to the appropriate interface as shown in the example below:

interface GigabitEthernet0/2
no switchport
ip address x.11.1.2 255.255.255.254
ip access-group EXTERNAL_ACL in
interface GigabitEthernet0/3
no switchport
ip address 10.1.12.2 255.255.255.0
ip access-group INTERNAL_ACL in

If the switch is not configured to restrict traffic destined to itself, this is a finding.

Check Content Reference

M

Target Key

4065

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