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The Cisco ASA must be configured to filter outbound traffic on all internal interfaces.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-239866CASA-FW-000240SV-239866r991798_ruleCCI-002403medium
Description
If outbound communications traffic is not filtered, hostile activity intended to harm other networks or packets from networks destined to unauthorized networks may not be detected and prevented. Access control policies and access control lists implemented on devices, such as firewalls, that control the flow of network traffic ensure the flow of traffic is only allowed from authorized sources to authorized destinations. Networks with different levels of trust (e.g., the Internet) must be kept separated. This requirement addresses the binding of the egress filter to the interface/zone rather than the content of the egress filter.
STIGDate
Cisco ASA Firewall Security Technical Implementation Guide2024-06-06

Related Frameworks

2 mappings across 3 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (5) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

CLD-03Cloud Infrastructure Security Subnet
0.50
NET-03Boundary Protection
0.50
NET-03.8Separate Subnet for Connecting to Different Security Domains
0.50
NET-04.1Deny Traffic by Default & Allow Traffic by Exception
0.50
NET-06.1Security Management Subnets
0.50
NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (11) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

AC-17(2)Protection of Confidentiality and Integrity Using Encryption
1.00
AC-3Access Enforcement
1.00
CM-6Configuration Settings
1.00
SC-24Fail in Known State
1.00
SC-47Alternate Communications Paths
1.00
SC-5Denial-of-service Protection
1.00
SC-7Boundary Protection
1.00
SC-7(11)Restrict Incoming Communications Traffic
1.00
SC-7(29)Separate Subnets to Isolate Functions
1.00
SC-7(5)Deny by Default — Allow by Exception
1.00

+1 more (top 10 by confidence shown)

CCI2 mappings
CCI-002403
1.00
CCI-004891
1.00

Details

Check Text (C-239866r991798_chk)

Step 1: Verify that an ingress ACL has been applied to the internal interface as shown in the example below. interface GigabitEthernet0/3 nameif INSIDE security-level 100 ip address 10.1.11.1 255.255.255.0 … … … access-group INSIDE_2_OUT in interface INSIDE Step 2: Verify that the ACL only allows outbound traffic using authorized ports and services as shown in the example below. access-list INSIDE_2_OUT extended permit tcp any any eq www access-list INSIDE_2_OUT extended permit tcp any any eq https access-list INSIDE_2_OUT extended permit tcp any any eq domain access-list INSIDE_2_OUT extended permit tcp any any eq ftp access-list INSIDE_2_OUT extended permit tcp any any eq ftp-data access-list INSIDE_2_OUT extended permit tcp any host 10.1.22.3 eq ssh access-list INSIDE_2_OUT extended deny ip any any log If the ASA is not configured to filter outbound traffic on all internal interfaces, this is a finding.

Fix Text (F-43058r665883_fix)

Step 1: Configure the egress ACL similar to the example below. ASA(config)# access-list INSIDE_2_OUT extended permit tcp any any eq https ASA(config)# access-list INSIDE_2_OUT extended permit tcp any any eq http ASA(config)# access-list INSIDE_2_OUT extended permit tcp any any eq domain ASA(config)# access-list INSIDE_2_OUT extended permit tcp any any eq ftp ASA(config)# access-list INSIDE_2_OUT extended permit tcp any any eq ftp-data ASA(config)# access-list INSIDE_2_OUT extended permit tcp any host 10.1.22.3 eq ssh ASA(config)# access-list INSIDE_2_OUT extended deny ip any any log Step 2: Apply the ACL inbound on the internal interfaces as shown in the example below. ASA(config)# access-group INSIDE_2_OUT in interface INSIDE ASA(config)# end