The Cisco ASA must be configured to implement cryptographic mechanisms using a FIPS 140-2 approved algorithm to protect the confidentiality of remote maintenance sessions.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
high	V-239931	SRG-APP-000412-NDM-000331	CASA-ND-001150	SV-239931r961557_rule	2024-08-22	2

Description
This requires the use of secure protocols instead of their unsecured counterparts, such as SSH instead of telnet, SCP instead of FTP, and HTTPS instead of HTTP. If unsecured protocols (lacking cryptographic mechanisms) are used for sessions, the contents of those sessions will be susceptible to eavesdropping, potentially putting sensitive data (including administrator passwords) at risk of compromise and potentially allowing hijacking of maintenance sessions.

Description

This requires the use of secure protocols instead of their unsecured counterparts, such as SSH instead of telnet, SCP instead of FTP, and HTTPS instead of HTTP. If unsecured protocols (lacking cryptographic mechanisms) are used for sessions, the contents of those sessions will be susceptible to eavesdropping, potentially putting sensitive data (including administrator passwords) at risk of compromise and potentially allowing hijacking of maintenance sessions.

ℹ️ Check
Step 1: Verify FIPS mode is enabled as shown in the example below. fips enable Step 2: Verify that only SSH is configured to only use FIPS-compliant ciphers and that Diffie-Hellman Group 14 is used for the key exchange as shown in the example below. ssh version 2 ssh cipher encryption fips ssh key-exchange group dh-group14-sha1 Note: The ASA only supports SSHv2. If the ASA is not configured to implement cryptographic mechanisms to protect the confidentiality of remote maintenance sessions using a FIPS 140-2 approved algorithm, this is a finding.

ℹ️ Check

Step 1: Verify FIPS mode is enabled as shown in the example below. fips enable Step 2: Verify that only SSH is configured to only use FIPS-compliant ciphers and that Diffie-Hellman Group 14 is used for the key exchange as shown in the example below. ssh version 2 ssh cipher encryption fips ssh key-exchange group dh-group14-sha1 Note: The ASA only supports SSHv2. If the ASA is not configured to implement cryptographic mechanisms to protect the confidentiality of remote maintenance sessions using a FIPS 140-2 approved algorithm, this is a finding.

✔️ Fix
Step 1: Enable FIPS mode via the fips enable command. Step 2: Configure SSH to only use FIPS-compliant ciphers and Diffie-Hellman Group 14 for the key exchange. ASA(config)# ssh cipher encryption fips ASA(config)# ssh key-exchange group dh-group14-sha