firewall

Firewall (egress advisor)

LuLu is the OSS per-process outbound firewall. Its rules live in /Library/Objective-See/LuLu/rules.plist (NSKeyedArchiver). lulu-cli (MIT, built for AI agents) reads/writes them from the command line; Netiquette snapshots live connections as JSON. This skill drives both — read-first, write only on approval.

Preflight

bash ${CLAUDE_PLUGIN_ROOT}/bin/install-tools.sh   # confirms lulu, lulu-cli, Netiquette

LuLu must have been launched once and its system extension approved. lulu-cli writes require sudo; surface the command, let the user run it.

Modes

Invocation	What it does
firewall (default)	Review posture: list current rules + snapshot live egress, attribute each destination, flag anything unexpected vs references/egress_baseline.md.
firewall rules	lulu-cli list — dump the current allow/block rule set, grouped by process.
firewall connections	Netiquette -list -names -pretty -skipApple → parse JSON, diff vs baseline, surface NEW listeners/flows.
firewall recent	lulu-cli recent 50 — most recently prompted/created rules (catches "what did I just approve").

Run

bash ${CLAUDE_PLUGIN_ROOT}/skills/firewall/scripts/firewall.sh

One read-only snapshot: LuLu status + rules + recent, live connections (Netiquette, lsof fallback), and app-firewall posture. Then diff against the baseline per the procedure below.

Procedure

1. Snapshot live egress (read-only, no sudo):

   Netiquette -list -names -pretty -skipApple
   

   Parse the JSON. For each process→remote, attribute the destination (cloud AI APIs, browser push, vendor telemetry, etc. — see references/egress_baseline.md).
2. List current LuLu rules:

   lulu-cli list
   

3. Diff both against references/egress_baseline.md. Surface only NEW destinations / processes. A flow to an unrecognized IP from an unexpected process is the finding.
4. For anything suspicious, hand the hash/destination to the malware-triage skill or run vt ip <addr> for reputation.
5. Propose rule changes as concrete commands; do NOT run writes yourself:

   sudo lulu-cli add --process "/path/bin" --action block --endpoint "1.2.3.4:443"
   sudo lulu-cli reload      # rules only load at ext startup; batch writes, then ONE reload
   

   Warn: reload restarts the system extension → ~8s filtering gap. Batch all changes, reload once.

Guardrails

• Read before write. Default mode never mutates rules.
• Batch + single reload. Never reload per-rule.
• Attribution over alarm. Most egress is legit vendor telemetry; name it, don't flag it.
• When confirmed-legit, append the destination to references/egress_baseline.md so it stops surfacing. See [[security-scan]] baseline pattern.

Files

• references/egress_baseline.md — known-good destinations + processes (diff target).