APPL-13-000056 - The macOS system must implement approved Key Exchange Algorithms within the SSH server configuration.

Information

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

Solution

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.

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Apple_macOS_13_V1R3_STIG.zip

Item Details

References: CAT|I, CCI|CCI-000068, CCI|CCI-000803, CCI|CCI-000877, CCI|CCI-001453, CCI|CCI-002890, CCI|CCI-003123, Rule-ID|SV-257167r919355_rule, STIG-ID|APPL-13-000056, Vuln-ID|V-257167

Plugin: Unix

Control ID: 9bd766510fdfc8cabb27e256efe4fee406d22e388ab3b869917096f6a843c581