fix: wire prober tcpfp_fingerprint events into sniffer_rollup for OS/hop detection
The active prober emits tcpfp_fingerprint events with TTL, window, MSS etc. from the attacker's SYN-ACK. These were invisible to the behavioral profiler for two reasons: 1. target_ip (prober's field name for attacker IP) was not in _IP_FIELDS in collector/worker.py or correlation/parser.py, so the profiler re-parsed raw_lines and got attacker_ip=None, never attributing prober events to the attacker profile. 2. sniffer_rollup only handled tcp_syn_fingerprint (passive sniffer) and ignored tcpfp_fingerprint (active prober). Prober events use different field names: window_size/window_scale/sack_ok vs window/wscale/has_sack. Changes: - Add target_ip to _IP_FIELDS in collector and parser - Add _PROBER_TCPFP_EVENT and _INITIAL_TTL table to behavioral.py - sniffer_rollup now processes tcpfp_fingerprint: maps field names, derives OS from TTL via _os_from_ttl, computes hop_distance = initial_ttl - observed - Expand prober DEFAULT_TCPFP_PORTS to [22,80,443,8080,8443,445,3389] for better SYN-ACK coverage on attacker machines - Add 4 tests covering prober OS detection, hop distance, and field mapping
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@@ -114,7 +114,7 @@ _RFC5424_RE = re.compile(
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)
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_SD_BLOCK_RE = re.compile(r'\[decnet@55555\s+(.*?)\]', re.DOTALL)
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_PARAM_RE = re.compile(r'(\w+)="((?:[^"\\]|\\.)*)"')
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_IP_FIELDS = ("src_ip", "src", "client_ip", "remote_ip", "remote_addr", "ip")
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_IP_FIELDS = ("src_ip", "src", "client_ip", "remote_ip", "remote_addr", "target_ip", "ip")
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def parse_rfc5424(line: str) -> Optional[dict[str, Any]]:
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@@ -38,7 +38,7 @@ _SD_BLOCK_RE = re.compile(r'\[decnet@55555\s+(.*?)\]', re.DOTALL)
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_PARAM_RE = re.compile(r'(\w+)="((?:[^"\\]|\\.)*)"')
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# Field names to probe for attacker IP, in priority order
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_IP_FIELDS = ("src_ip", "src", "client_ip", "remote_ip", "remote_addr", "ip")
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_IP_FIELDS = ("src_ip", "src", "client_ip", "remote_ip", "remote_addr", "target_ip", "ip")
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@dataclass
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@@ -43,8 +43,9 @@ DEFAULT_PROBE_PORTS: list[int] = [
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# HASSHServer: common SSH server ports
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DEFAULT_SSH_PORTS: list[int] = [22, 2222, 22222, 2022]
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# TCP/IP stack: probe on common service ports
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DEFAULT_TCPFP_PORTS: list[int] = [80, 443]
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# TCP/IP stack: probe on ports commonly open on attacker machines.
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# Wide spread gives the best chance of a SYN-ACK for TTL/fingerprint extraction.
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DEFAULT_TCPFP_PORTS: list[int] = [22, 80, 443, 8080, 8443, 445, 3389]
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# ─── RFC 5424 formatting (inline, mirrors templates/*/decnet_logging.py) ─────
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@@ -35,8 +35,18 @@ from decnet.correlation.parser import LogEvent
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# ─── Event-type taxonomy ────────────────────────────────────────────────────
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# Sniffer-emitted packet events that feed into fingerprint rollup.
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_SNIFFER_SYN_EVENT: str = "tcp_syn_fingerprint"
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_SNIFFER_SYN_EVENT: str = "tcp_syn_fingerprint"
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_SNIFFER_FLOW_EVENT: str = "tcp_flow_timing"
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# Prober-emitted active-probe result (SYN-ACK fingerprint of attacker machine).
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_PROBER_TCPFP_EVENT: str = "tcpfp_fingerprint"
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# Canonical initial TTL for each coarse OS bucket. Used to derive hop
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# distance when only the observed TTL is available (prober path).
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_INITIAL_TTL: dict[str, int] = {
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"linux": 64,
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"windows": 128,
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"embedded": 255,
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}
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# Events that signal "recon" phase (scans, probes, auth attempts).
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_RECON_EVENT_TYPES: frozenset[str] = frozenset({
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@@ -461,6 +471,36 @@ def sniffer_rollup(events: list[LogEvent]) -> dict[str, Any]:
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except (TypeError, ValueError):
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pass
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elif e.event_type == _PROBER_TCPFP_EVENT:
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# Active-probe result: prober sent SYN to attacker, got SYN-ACK back.
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# Field names differ from the passive sniffer (different emitter).
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ttl_raw = e.fields.get("ttl")
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if ttl_raw:
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ttl_values.append(ttl_raw)
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# Derive hop distance from observed TTL vs canonical initial TTL.
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os_hint = _os_from_ttl(ttl_raw)
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if os_hint:
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initial = _INITIAL_TTL.get(os_hint)
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if initial:
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try:
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hop_val = initial - int(ttl_raw)
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if hop_val > 0:
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hops.append(hop_val)
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except (TypeError, ValueError):
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pass
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# Prober uses window_size/window_scale/options_order instead of
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# the sniffer's window/wscale/options_sig.
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tcp_fp = {
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"window": _int_or_none(e.fields.get("window_size")),
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"wscale": _int_or_none(e.fields.get("window_scale")),
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"mss": _int_or_none(e.fields.get("mss")),
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"options_sig": e.fields.get("options_order", ""),
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"has_sack": e.fields.get("sack_ok") == "1",
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"has_timestamps": e.fields.get("timestamp") == "1",
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}
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# Mode for the OS bucket — most frequently observed label.
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os_guess: str | None = None
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if os_guesses:
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@@ -423,6 +423,45 @@ class TestSnifferRollup:
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r = sniffer_rollup(events)
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assert r["os_guess"] == "macos_ios"
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def test_prober_tcpfp_os_from_ttl(self):
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# Active-probe event: TTL=121 → windows OS guess.
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events = [
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_mk(0, event_type="tcpfp_fingerprint",
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fields={"ttl": "121", "window_size": "64240", "mss": "1460",
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"window_scale": "8", "sack_ok": "1", "timestamp": "0",
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"options_order": "M,N,W,N,N,S"}),
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]
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r = sniffer_rollup(events)
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assert r["os_guess"] == "windows"
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def test_prober_tcpfp_hop_distance_derived(self):
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# TTL=121 with windows initial TTL=128 → hop_distance=7.
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events = [
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_mk(0, event_type="tcpfp_fingerprint",
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fields={"ttl": "121", "window_size": "64240", "mss": "1460",
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"window_scale": "8", "sack_ok": "1", "timestamp": "0",
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"options_order": "M,N,W,N,N,S"}),
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]
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r = sniffer_rollup(events)
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assert r["hop_distance"] == 7
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def test_prober_tcpfp_tcp_fingerprint_fields(self):
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# Prober field names (window_size, window_scale, etc.) are mapped correctly.
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events = [
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_mk(0, event_type="tcpfp_fingerprint",
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fields={"ttl": "60", "window_size": "29200", "mss": "1460",
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"window_scale": "7", "sack_ok": "1", "timestamp": "1",
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"options_order": "M,N,W,N,N,T,S,E"}),
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]
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r = sniffer_rollup(events)
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fp = r["tcp_fingerprint"]
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assert fp["window"] == 29200
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assert fp["wscale"] == 7
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assert fp["mss"] == 1460
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assert fp["has_sack"] is True
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assert fp["has_timestamps"] is True
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assert fp["options_sig"] == "M,N,W,N,N,T,S,E"
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# ─── build_behavior_record (composite) ──────────────────────────────────────
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