Title

The Cisco ASA must be configured with only one local account to be used as the account of last resort in the event the authentication server is unavailable. (Cat II impact)

Discussion

Authentication for administrative (privileged level) access to the device is required at all times. An account can be created on the device's local database for use when the authentication server is down or connectivity between the device and the authentication server is not operable. This account is referred to as the account of last resort since it is intended to be used as a last resort and when immediate administrative access is absolutely necessary. The account of last resort logon credentials must be stored in a sealed envelope and kept in a safe. The safe must be periodically audited to verify the envelope remains sealed. The signature of the auditor and the date of the audit should be added to the envelope as a record. Administrators should secure the credentials and disable the root account (if possible) when not needed for system administration functions.

Check Content

Step 1: Review the Cisco ASA configuration to verify that a local account for last resort has been configured with a privilege level that will enable the administrator to troubleshoot connectivity to the authentication server. username LAST_RESORT password $sha512$5000$tb2eaIcI/Q5Q==$ScFJI1ChS4gIjXw== pbkdf2 privilege 15 Step 2: Verify the fallback to use local account has been configured as shown in the example below. user-identity default-domain LOCAL aaa authentication serial console RADIUS_GROUP LOCAL aaa authentication ssh console RADIUS_GROUP LOCAL If the Cisco ASA is not configured with only one local account to be used as the account of last resort in the event the authentication server is unavailable, this is a finding.

Fix Text

Step 1: Configure a local account with the necessary privilege level to troubleshoot network outage and restore operations as shown in the following example. ASA(config)# username LAST_RESORT privilege 15 ASA(config)# username LAST_RESORT password xxxxxxxxxxxxx Step 2: Define the AAA server. ASA(config)# aaa-server RADIUS_GROUP protocol radius ASA(config-aaa-server-group)# exit ASA(config)# aaa-server RADIUS_GROUP (NDM_INTERFACE) host 10.1.48.10 ASA(config-aaa-server-host)# key xxxxxxxxx ASA(config-aaa-server-host)# exit Step 3: Configure the authentication to use an AAA server with the fallback to use the local account if the authentication server is not reachable as shown in the following example. ASA(config)# aaa authentication serial console RADIUS_GROUP LOCAL ASA(config)# aaa authentication ssh console RADIUS_GROUP LOCAL ASA(config)# end

Additional Identifiers

Rule ID: SV-239912r879589_rule

Vulnerability ID: V-239912

Group Title: SRG-APP-000148-NDM-000346

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.