WIP/POC: RAN Hardening (High): Top 5 SSHD

[sebrandon1]

Based on changes from: #339

I'm breaking down the high level compliance remediation objects into smaller and more manageable and reviewable YAML files. I asked AI to help me break down the 5 highest priority flags from #339 and put them in their own individual files.

Files Added

• 75-sshd_config-base.yaml - Enables the /etc/ssh/sshd_config.d/ include directory for modular SSH configuration management

• 76-sshd-disable-root-login.yaml - Disables direct root SSH access (PermitRootLogin no), forcing use of privilege escalation for administrative tasks

• 77-sshd-disable-password-auth.yaml - Disables password-based authentication (PasswordAuthentication no, PermitEmptyPasswords no) to prevent brute-force attacks, password spraying, and credential stuffing

• 78-sshd-session-timeout.yaml - Implements automatic session timeout after 5 minutes of inactivity (ClientAliveInterval 300, ClientAliveCountMax 0) to prevent abandoned session hijacking

• 79-sshd-enable-pubkey-auth.yaml - Explicitly enables public key authentication (PubkeyAuthentication yes) as the primary authentication method

[openshift-ci]

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[sebrandon1]

Closing in favor of: #466