Check: APPL-12-000056
Apple macOS 12 (Monterey) STIG:
APPL-12-000056
(in version v1 r8)
Title
The macOS system must implement approved Key Exchange Algorithms within the SSH server configuration. (Cat I impact)
Discussion
Operating systems using encryption are required to use FIPS-compliant mechanisms for authenticating to macOS. For OpenSSH to utilize the Apple Corecrypto FIPS-validated algorithms, a specific configuration is required to leverage the shim implemented by macOS to bypass the non-FIPS validated LibreSSL crypto module packaged with OpenSSH. Information regarding this configuration can be found in the manual page "apple_ssh_and_fips". Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00176
Check Content
Verify the macOS system is configured to use approved SSH Key Exchange Algorithms within the SSH server configuration with the following command: /usr/bin/sudo /usr/sbin/sshd -T | /usr/bin/grep "kexalgorithms" kexalgorithms ecdh-sha2-nistp256 If any algorithms other than "ecdh-sha2-nistp256" are listed, or the "kexalgorithms" keyword is missing, this is a finding.
Fix Text
Configure the macOS system to use approved SSH Key Exchange Algorithms by creating a plain text file in the /private/etc/ssh/sshd_config.d/ directory containing the following: KexAlgorithms ecdh-sha2-nistp256 The SSH service must be restarted for changes to take effect.
Additional Identifiers
Rule ID: SV-252461r922861_rule
Vulnerability ID: V-252461
Group Title: SRG-OS-000033-GPOS-00014
Expert Comments
CCIs
| Number | Definition |
|---|---|
| CCI-000068 |
The information system implements cryptographic mechanisms to protect the confidentiality of remote access sessions. |
| CCI-000803 |
The information system implements mechanisms for authentication to a cryptographic module that meet the requirements of applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance for such authentication. |
| CCI-002890 |
The information system implements cryptographic mechanisms to protect the integrity of nonlocal maintenance and diagnostic communications. |
| CCI-003123 |
The information system implements cryptographic mechanisms to protect the confidentiality of nonlocal maintenance and diagnostic communications. |