Security & TLS · pro · solved in-browser (no VM needed) · 3 tiered hints
Write /home/player/v3.ext, an OpenSSL x509 v3 extension file used when signing a leaf certificate. Set basicConstraints to CA:FALSE, set keyUsage to 'digitalSignature, keyEncipherment', set extendedKeyUsage to serverAuth, and add a subjectAltName line referencing an alt_names section that defines DNS.1 = tmpfs.lab. (Authored config, graded structurally — the engine isn't run here.)
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Certificates, signatures, hardening sshd and verifying trust.
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How is it graded? Automatically and deterministically — your work is checked against the exact rules the live box would apply.