feat: add HASSHServer and TCP/IP stack fingerprinting to DECNET-PROBER

Extends the prober with two new active probe types alongside JARM: - HASSHServer: SSH server fingerprinting via KEX_INIT algorithm ordering (MD5 hash of kex;enc_s2c;mac_s2c;comp_s2c, pure stdlib) - TCP/IP stack: OS/tool fingerprinting via SYN-ACK analysis using scapy (TTL, window size, DF bit, MSS, TCP options ordering, SHA256 hash) Worker probe cycle now runs three phases per IP with independent per-type port tracking. Ingester extracts bounties for all three fingerprint types.
2026-04-14 12:53:55 -04:00
parent 5585e4ec58
commit 2dcf47985e
9 changed files with 1843 additions and 81 deletions
--- a/tests/test_prober_bounty.py
+++ b/tests/test_prober_bounty.py
@@ -1,8 +1,9 @@
 """
-Tests for JARM bounty extraction in the ingester.
+Tests for prober bounty extraction in the ingester.

-Verifies that _extract_bounty() correctly identifies and stores JARM
-fingerprints from prober events, and ignores JARM fields from other services.
+Verifies that _extract_bounty() correctly identifies and stores JARM,
+HASSH, and TCP/IP fingerprints from prober events, and ignores these
+fields when they come from other services.
 """

 from __future__ import annotations
@@ -112,3 +113,131 @@ async def test_jarm_bounty_missing_fields_dict():
    for call in repo.add_bounty.call_args_list:
        payload = call[0][0].get("payload", {})
        assert payload.get("fingerprint_type") != "jarm"
+
+
+# ─── HASSH bounty extraction ───────────────────────────────────────────────
+
+@pytest.mark.asyncio
+async def test_hassh_bounty_extracted():
+    """Prober event with hassh_server_hash should create a fingerprint bounty."""
+    repo = _make_repo()
+    log_data = {
+        "decky": "decnet-prober",
+        "service": "prober",
+        "event_type": "hassh_fingerprint",
+        "attacker_ip": "Unknown",
+        "fields": {
+            "target_ip": "10.0.0.1",
+            "target_port": "22",
+            "hassh_server_hash": "a" * 32,
+            "ssh_banner": "SSH-2.0-OpenSSH_8.9p1",
+            "kex_algorithms": "curve25519-sha256",
+            "encryption_s2c": "aes256-gcm@openssh.com",
+            "mac_s2c": "hmac-sha2-256-etm@openssh.com",
+            "compression_s2c": "none",
+        },
+        "msg": "HASSH 10.0.0.1:22 = ...",
+    }
+
+    await _extract_bounty(repo, log_data)
+
+    # Find the HASSH bounty call
+    hassh_calls = [
+        c for c in repo.add_bounty.call_args_list
+        if c[0][0].get("payload", {}).get("fingerprint_type") == "hassh_server"
+    ]
+    assert len(hassh_calls) == 1
+    payload = hassh_calls[0][0][0]["payload"]
+    assert payload["hash"] == "a" * 32
+    assert payload["ssh_banner"] == "SSH-2.0-OpenSSH_8.9p1"
+    assert payload["kex_algorithms"] == "curve25519-sha256"
+    assert payload["encryption_s2c"] == "aes256-gcm@openssh.com"
+    assert payload["mac_s2c"] == "hmac-sha2-256-etm@openssh.com"
+    assert payload["compression_s2c"] == "none"
+
+
+@pytest.mark.asyncio
+async def test_hassh_bounty_not_extracted_from_other_services():
+    """A non-prober event with hassh_server_hash should NOT trigger extraction."""
+    repo = _make_repo()
+    log_data = {
+        "decky": "decky-01",
+        "service": "ssh",
+        "event_type": "login_attempt",
+        "attacker_ip": "192.168.1.50",
+        "fields": {
+            "hassh_server_hash": "fake_hash",
+        },
+        "msg": "",
+    }
+
+    await _extract_bounty(repo, log_data)
+
+    for call in repo.add_bounty.call_args_list:
+        payload = call[0][0].get("payload", {})
+        assert payload.get("fingerprint_type") != "hassh_server"
+
+
+# ─── TCP/IP fingerprint bounty extraction ──────────────────────────────────
+
+@pytest.mark.asyncio
+async def test_tcpfp_bounty_extracted():
+    """Prober event with tcpfp_hash should create a fingerprint bounty."""
+    repo = _make_repo()
+    log_data = {
+        "decky": "decnet-prober",
+        "service": "prober",
+        "event_type": "tcpfp_fingerprint",
+        "attacker_ip": "Unknown",
+        "fields": {
+            "target_ip": "10.0.0.1",
+            "target_port": "443",
+            "tcpfp_hash": "d" * 32,
+            "tcpfp_raw": "64:65535:1:1460:7:1:1:M,N,W,N,N,T,S,E",
+            "ttl": "64",
+            "window_size": "65535",
+            "df_bit": "1",
+            "mss": "1460",
+            "window_scale": "7",
+            "sack_ok": "1",
+            "timestamp": "1",
+            "options_order": "M,N,W,N,N,T,S,E",
+        },
+        "msg": "TCPFP 10.0.0.1:443 = ...",
+    }
+
+    await _extract_bounty(repo, log_data)
+
+    tcpfp_calls = [
+        c for c in repo.add_bounty.call_args_list
+        if c[0][0].get("payload", {}).get("fingerprint_type") == "tcpfp"
+    ]
+    assert len(tcpfp_calls) == 1
+    payload = tcpfp_calls[0][0][0]["payload"]
+    assert payload["hash"] == "d" * 32
+    assert payload["raw"] == "64:65535:1:1460:7:1:1:M,N,W,N,N,T,S,E"
+    assert payload["ttl"] == "64"
+    assert payload["window_size"] == "65535"
+    assert payload["options_order"] == "M,N,W,N,N,T,S,E"
+
+
+@pytest.mark.asyncio
+async def test_tcpfp_bounty_not_extracted_from_other_services():
+    """A non-prober event with tcpfp_hash should NOT trigger extraction."""
+    repo = _make_repo()
+    log_data = {
+        "decky": "decky-01",
+        "service": "sniffer",
+        "event_type": "something",
+        "attacker_ip": "192.168.1.50",
+        "fields": {
+            "tcpfp_hash": "fake_hash",
+        },
+        "msg": "",
+    }
+
+    await _extract_bounty(repo, log_data)
+
+    for call in repo.add_bounty.call_args_list:
+        payload = call[0][0].get("payload", {})
+        assert payload.get("fingerprint_type") != "tcpfp"
--- a/tests/test_prober_hassh.py
+++ b/tests/test_prober_hassh.py
@@ -0,0 +1,357 @@
+"""
+Unit tests for the HASSHServer SSH fingerprinting module.
+
+Tests cover KEX_INIT parsing, HASSH hash computation, SSH connection
+handling, and end-to-end hassh_server() with mocked sockets.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import socket
+import struct
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from decnet.prober.hassh import (
+    _CLIENT_BANNER,
+    _SSH_MSG_KEXINIT,
+    _compute_hassh,
+    _parse_kex_init,
+    _read_banner,
+    _read_ssh_packet,
+    hassh_server,
+)
+
+
+# ─── Helpers ────────────────────────────────────────────────────────────────
+
+def _build_name_list(value: str) -> bytes:
+    """Encode a single SSH name-list (uint32 length + utf-8 string)."""
+    encoded = value.encode("utf-8")
+    return struct.pack("!I", len(encoded)) + encoded
+
+
+def _build_kex_init(
+    kex: str = "curve25519-sha256,diffie-hellman-group14-sha256",
+    host_key: str = "ssh-ed25519,rsa-sha2-512",
+    enc_c2s: str = "aes256-gcm@openssh.com,aes128-gcm@openssh.com",
+    enc_s2c: str = "aes256-gcm@openssh.com,chacha20-poly1305@openssh.com",
+    mac_c2s: str = "hmac-sha2-256-etm@openssh.com",
+    mac_s2c: str = "hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com",
+    comp_c2s: str = "none,zlib@openssh.com",
+    comp_s2c: str = "none,zlib@openssh.com",
+    lang_c2s: str = "",
+    lang_s2c: str = "",
+    cookie: bytes | None = None,
+) -> bytes:
+    """Build a complete SSH_MSG_KEXINIT payload for testing."""
+    if cookie is None:
+        cookie = b"\x00" * 16
+
+    payload = struct.pack("B", _SSH_MSG_KEXINIT) + cookie
+    for value in [kex, host_key, enc_c2s, enc_s2c, mac_c2s, mac_s2c,
+                  comp_c2s, comp_s2c, lang_c2s, lang_s2c]:
+        payload += _build_name_list(value)
+    # first_kex_packet_follows (bool) + reserved (uint32)
+    payload += struct.pack("!BI", 0, 0)
+    return payload
+
+
+def _wrap_ssh_packet(payload: bytes) -> bytes:
+    """Wrap payload into an SSH binary packet (header only, no MAC)."""
+    # Padding to 8-byte boundary (minimum 4 bytes)
+    block_size = 8
+    padding_needed = block_size - ((1 + len(payload)) % block_size)
+    if padding_needed < 4:
+        padding_needed += block_size
+    padding = b"\x00" * padding_needed
+    packet_length = 1 + len(payload) + len(padding)  # padding_length(1) + payload + padding
+    return struct.pack("!IB", packet_length, padding_needed) + payload + padding
+
+
+def _make_socket_with_data(data: bytes) -> MagicMock:
+    """Create a mock socket that yields data byte-by-byte or in chunks."""
+    sock = MagicMock()
+    pos = [0]
+
+    def recv(n):
+        if pos[0] >= len(data):
+            return b""
+        chunk = data[pos[0] : pos[0] + n]
+        pos[0] += n
+        return chunk
+
+    sock.recv = recv
+    return sock
+
+
+# ─── _parse_kex_init ────────────────────────────────────────────────────────
+
+class TestParseKexInit:
+
+    def test_parses_all_ten_fields(self):
+        payload = _build_kex_init()
+        result = _parse_kex_init(payload)
+        assert result is not None
+        assert len(result) == 10
+
+    def test_extracts_correct_field_values(self):
+        payload = _build_kex_init(
+            kex="curve25519-sha256",
+            enc_s2c="chacha20-poly1305@openssh.com",
+            mac_s2c="hmac-sha2-512-etm@openssh.com",
+            comp_s2c="none",
+        )
+        result = _parse_kex_init(payload)
+        assert result["kex_algorithms"] == "curve25519-sha256"
+        assert result["encryption_server_to_client"] == "chacha20-poly1305@openssh.com"
+        assert result["mac_server_to_client"] == "hmac-sha2-512-etm@openssh.com"
+        assert result["compression_server_to_client"] == "none"
+
+    def test_extracts_hassh_server_fields_at_correct_indices(self):
+        """HASSHServer uses indices 0(kex), 3(enc_s2c), 5(mac_s2c), 7(comp_s2c)."""
+        payload = _build_kex_init(
+            kex="KEX_FIELD",
+            host_key="HOSTKEY_FIELD",
+            enc_c2s="ENC_C2S_FIELD",
+            enc_s2c="ENC_S2C_FIELD",
+            mac_c2s="MAC_C2S_FIELD",
+            mac_s2c="MAC_S2C_FIELD",
+            comp_c2s="COMP_C2S_FIELD",
+            comp_s2c="COMP_S2C_FIELD",
+        )
+        result = _parse_kex_init(payload)
+        # Indices used by HASSHServer
+        assert result["kex_algorithms"] == "KEX_FIELD"               # index 0
+        assert result["encryption_server_to_client"] == "ENC_S2C_FIELD"  # index 3
+        assert result["mac_server_to_client"] == "MAC_S2C_FIELD"     # index 5
+        assert result["compression_server_to_client"] == "COMP_S2C_FIELD"  # index 7
+
+    def test_empty_name_lists(self):
+        payload = _build_kex_init(
+            kex="", host_key="", enc_c2s="", enc_s2c="",
+            mac_c2s="", mac_s2c="", comp_c2s="", comp_s2c="",
+        )
+        result = _parse_kex_init(payload)
+        assert result is not None
+        assert result["kex_algorithms"] == ""
+
+    def test_truncated_payload_returns_none(self):
+        # Just the type byte and cookie, no name-lists
+        payload = struct.pack("B", _SSH_MSG_KEXINIT) + b"\x00" * 16
+        assert _parse_kex_init(payload) is None
+
+    def test_truncated_name_list_returns_none(self):
+        # Type + cookie + length says 100 but only 2 bytes follow
+        payload = struct.pack("B", _SSH_MSG_KEXINIT) + b"\x00" * 16
+        payload += struct.pack("!I", 100) + b"ab"
+        assert _parse_kex_init(payload) is None
+
+    def test_too_short_returns_none(self):
+        assert _parse_kex_init(b"") is None
+        assert _parse_kex_init(b"\x14") is None
+
+    def test_large_algorithm_lists(self):
+        long_kex = ",".join(f"algo-{i}" for i in range(50))
+        payload = _build_kex_init(kex=long_kex)
+        result = _parse_kex_init(payload)
+        assert result is not None
+        assert result["kex_algorithms"] == long_kex
+
+
+# ─── _compute_hassh ─────────────────────────────────────────────────────────
+
+class TestComputeHashh:
+
+    def test_md5_correctness(self):
+        kex = "curve25519-sha256"
+        enc = "aes256-gcm@openssh.com"
+        mac = "hmac-sha2-256-etm@openssh.com"
+        comp = "none"
+        raw = f"{kex};{enc};{mac};{comp}"
+        expected = hashlib.md5(raw.encode("utf-8")).hexdigest()
+        assert _compute_hassh(kex, enc, mac, comp) == expected
+
+    def test_hash_length_is_32(self):
+        result = _compute_hassh("a", "b", "c", "d")
+        assert len(result) == 32
+
+    def test_deterministic(self):
+        r1 = _compute_hassh("kex1", "enc1", "mac1", "comp1")
+        r2 = _compute_hassh("kex1", "enc1", "mac1", "comp1")
+        assert r1 == r2
+
+    def test_different_inputs_different_hashes(self):
+        r1 = _compute_hassh("kex1", "enc1", "mac1", "comp1")
+        r2 = _compute_hassh("kex2", "enc2", "mac2", "comp2")
+        assert r1 != r2
+
+    def test_empty_fields(self):
+        result = _compute_hassh("", "", "", "")
+        expected = hashlib.md5(b";;;").hexdigest()
+        assert result == expected
+
+    def test_semicolon_delimiter(self):
+        """The delimiter is semicolon, not comma."""
+        result = _compute_hassh("a", "b", "c", "d")
+        expected = hashlib.md5(b"a;b;c;d").hexdigest()
+        assert result == expected
+
+
+# ─── _read_banner ───────────────────────────────────────────────────────────
+
+class TestReadBanner:
+
+    def test_reads_banner_with_crlf(self):
+        sock = _make_socket_with_data(b"SSH-2.0-OpenSSH_8.9p1\r\n")
+        result = _read_banner(sock)
+        assert result == "SSH-2.0-OpenSSH_8.9p1"
+
+    def test_reads_banner_with_lf(self):
+        sock = _make_socket_with_data(b"SSH-2.0-OpenSSH_8.9p1\n")
+        result = _read_banner(sock)
+        assert result == "SSH-2.0-OpenSSH_8.9p1"
+
+    def test_empty_data_returns_none(self):
+        sock = _make_socket_with_data(b"")
+        result = _read_banner(sock)
+        assert result is None
+
+    def test_no_newline_within_limit(self):
+        # 256 bytes with no newline — should stop at limit
+        sock = _make_socket_with_data(b"A" * 256)
+        result = _read_banner(sock)
+        assert result == "A" * 256
+
+
+# ─── _read_ssh_packet ───────────────────────────────────────────────────────
+
+class TestReadSSHPacket:
+
+    def test_reads_valid_packet(self):
+        payload = b"\x14" + b"\x00" * 20  # type 20 + some data
+        packet_data = _wrap_ssh_packet(payload)
+        sock = _make_socket_with_data(packet_data)
+        result = _read_ssh_packet(sock)
+        assert result is not None
+        assert result[0] == 0x14  # SSH_MSG_KEXINIT
+
+    def test_empty_socket_returns_none(self):
+        sock = _make_socket_with_data(b"")
+        assert _read_ssh_packet(sock) is None
+
+    def test_truncated_header_returns_none(self):
+        sock = _make_socket_with_data(b"\x00\x00")
+        assert _read_ssh_packet(sock) is None
+
+    def test_oversized_packet_returns_none(self):
+        # packet_length = 40000 (over limit)
+        sock = _make_socket_with_data(struct.pack("!I", 40000))
+        assert _read_ssh_packet(sock) is None
+
+    def test_zero_length_returns_none(self):
+        sock = _make_socket_with_data(struct.pack("!I", 0))
+        assert _read_ssh_packet(sock) is None
+
+
+# ─── hassh_server (end-to-end with mocked sockets) ─────────────────────────
+
+class TestHasshServerE2E:
+
+    @patch("decnet.prober.hassh._ssh_connect")
+    def test_success(self, mock_connect: MagicMock):
+        payload = _build_kex_init(
+            kex="curve25519-sha256",
+            enc_s2c="aes256-gcm@openssh.com",
+            mac_s2c="hmac-sha2-256-etm@openssh.com",
+            comp_s2c="none",
+        )
+        mock_connect.return_value = ("SSH-2.0-OpenSSH_8.9p1", payload)
+
+        result = hassh_server("10.0.0.1", 22, timeout=1.0)
+        assert result is not None
+        assert len(result["hassh_server"]) == 32
+        assert result["banner"] == "SSH-2.0-OpenSSH_8.9p1"
+        assert result["kex_algorithms"] == "curve25519-sha256"
+        assert result["encryption_s2c"] == "aes256-gcm@openssh.com"
+        assert result["mac_s2c"] == "hmac-sha2-256-etm@openssh.com"
+        assert result["compression_s2c"] == "none"
+
+    @patch("decnet.prober.hassh._ssh_connect")
+    def test_connection_failure_returns_none(self, mock_connect: MagicMock):
+        mock_connect.return_value = None
+        assert hassh_server("10.0.0.1", 22, timeout=1.0) is None
+
+    @patch("decnet.prober.hassh._ssh_connect")
+    def test_truncated_kex_init_returns_none(self, mock_connect: MagicMock):
+        # Payload too short to parse
+        payload = struct.pack("B", _SSH_MSG_KEXINIT) + b"\x00" * 16
+        mock_connect.return_value = ("SSH-2.0-OpenSSH_8.9p1", payload)
+        assert hassh_server("10.0.0.1", 22, timeout=1.0) is None
+
+    @patch("decnet.prober.hassh._ssh_connect")
+    def test_hash_is_deterministic(self, mock_connect: MagicMock):
+        payload = _build_kex_init()
+        mock_connect.return_value = ("SSH-2.0-OpenSSH_8.9p1", payload)
+
+        r1 = hassh_server("10.0.0.1", 22)
+        r2 = hassh_server("10.0.0.1", 22)
+        assert r1["hassh_server"] == r2["hassh_server"]
+
+    @patch("decnet.prober.hassh._ssh_connect")
+    def test_different_servers_different_hashes(self, mock_connect: MagicMock):
+        p1 = _build_kex_init(kex="curve25519-sha256", enc_s2c="aes256-gcm@openssh.com")
+        p2 = _build_kex_init(kex="diffie-hellman-group14-sha1", enc_s2c="aes128-cbc")
+
+        mock_connect.return_value = ("SSH-2.0-OpenSSH_8.9p1", p1)
+        r1 = hassh_server("10.0.0.1", 22)
+
+        mock_connect.return_value = ("SSH-2.0-Paramiko_3.0", p2)
+        r2 = hassh_server("10.0.0.2", 22)
+
+        assert r1["hassh_server"] != r2["hassh_server"]
+
+    @patch("decnet.prober.hassh.socket.create_connection")
+    def test_full_socket_mock(self, mock_create: MagicMock):
+        """Full integration: mock at socket level, verify banner exchange."""
+        kex_payload = _build_kex_init()
+        kex_packet = _wrap_ssh_packet(kex_payload)
+
+        banner_bytes = b"SSH-2.0-OpenSSH_8.9p1\r\n"
+        all_data = banner_bytes + kex_packet
+
+        mock_sock = _make_socket_with_data(all_data)
+        mock_sock.sendall = MagicMock()
+        mock_sock.settimeout = MagicMock()
+        mock_sock.close = MagicMock()
+        mock_create.return_value = mock_sock
+
+        result = hassh_server("10.0.0.1", 22, timeout=2.0)
+        assert result is not None
+        assert result["banner"] == "SSH-2.0-OpenSSH_8.9p1"
+        assert len(result["hassh_server"]) == 32
+
+        # Verify we sent our client banner
+        mock_sock.sendall.assert_called_once_with(_CLIENT_BANNER)
+
+    @patch("decnet.prober.hassh.socket.create_connection")
+    def test_non_ssh_banner_returns_none(self, mock_create: MagicMock):
+        mock_sock = _make_socket_with_data(b"HTTP/1.1 200 OK\r\n")
+        mock_sock.sendall = MagicMock()
+        mock_sock.settimeout = MagicMock()
+        mock_sock.close = MagicMock()
+        mock_create.return_value = mock_sock
+
+        assert hassh_server("10.0.0.1", 80, timeout=1.0) is None
+
+    @patch("decnet.prober.hassh.socket.create_connection")
+    def test_connection_refused(self, mock_create: MagicMock):
+        mock_create.side_effect = ConnectionRefusedError
+        assert hassh_server("10.0.0.1", 22, timeout=1.0) is None
+
+    @patch("decnet.prober.hassh.socket.create_connection")
+    def test_timeout(self, mock_create: MagicMock):
+        mock_create.side_effect = socket.timeout("timed out")
+        assert hassh_server("10.0.0.1", 22, timeout=1.0) is None
--- a/tests/test_prober_tcpfp.py
+++ b/tests/test_prober_tcpfp.py
@@ -0,0 +1,349 @@
+"""
+Unit tests for the TCP/IP stack fingerprinting module.
+
+Tests cover SYN-ACK parsing, options extraction, fingerprint computation,
+and end-to-end tcp_fingerprint() with mocked scapy packets.
+"""
+
+from __future__ import annotations
+
+import hashlib
+from types import SimpleNamespace
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from decnet.prober.tcpfp import (
+    _compute_fingerprint,
+    _extract_options_order,
+    _parse_synack,
+    tcp_fingerprint,
+)
+
+
+# ─── Helpers ────────────────────────────────────────────────────────────────
+
+def _make_synack(
+    ttl: int = 64,
+    flags: int = 0x02,  # IP flags (DF = 0x02)
+    ip_id: int = 0,
+    window: int = 65535,
+    tcp_flags: int = 0x12,  # SYN-ACK
+    options: list | None = None,
+    ack: int = 1,
+) -> SimpleNamespace:
+    """Build a fake scapy-like SYN-ACK packet for testing."""
+    if options is None:
+        options = [
+            ("MSS", 1460),
+            ("NOP", None),
+            ("WScale", 7),
+            ("NOP", None),
+            ("NOP", None),
+            ("Timestamp", (12345, 0)),
+            ("SAckOK", b""),
+            ("EOL", None),
+        ]
+
+    tcp_layer = SimpleNamespace(
+        flags=tcp_flags,
+        window=window,
+        options=options,
+        dport=12345,
+        ack=ack,
+    )
+    ip_layer = SimpleNamespace(
+        ttl=ttl,
+        flags=flags,
+        id=ip_id,
+    )
+
+    class FakePacket:
+        def __init__(self):
+            self._layers = {"IP": ip_layer, "TCP": tcp_layer}
+            self.ack = ack
+
+        def __getitem__(self, key):
+            # Support both class and string access
+            name = key.__name__ if hasattr(key, "__name__") else str(key)
+            return self._layers[name]
+
+        def haslayer(self, key):
+            name = key.__name__ if hasattr(key, "__name__") else str(key)
+            return name in self._layers
+
+    return FakePacket()
+
+
+# ─── _extract_options_order ─────────────────────────────────────────────────
+
+class TestExtractOptionsOrder:
+
+    def test_standard_linux_options(self):
+        options = [
+            ("MSS", 1460), ("NOP", None), ("WScale", 7),
+            ("NOP", None), ("NOP", None), ("Timestamp", (0, 0)),
+            ("SAckOK", b""), ("EOL", None),
+        ]
+        assert _extract_options_order(options) == "M,N,W,N,N,T,S,E"
+
+    def test_windows_options(self):
+        options = [
+            ("MSS", 1460), ("NOP", None), ("WScale", 8),
+            ("NOP", None), ("NOP", None), ("SAckOK", b""),
+        ]
+        assert _extract_options_order(options) == "M,N,W,N,N,S"
+
+    def test_empty_options(self):
+        assert _extract_options_order([]) == ""
+
+    def test_mss_only(self):
+        assert _extract_options_order([("MSS", 536)]) == "M"
+
+    def test_unknown_option(self):
+        options = [("MSS", 1460), ("UnknownOpt", 42)]
+        assert _extract_options_order(options) == "M,?"
+
+    def test_sack_variant(self):
+        options = [("SAck", (100, 200))]
+        assert _extract_options_order(options) == "S"
+
+
+# ─── _parse_synack ──────────────────────────────────────────────────────────
+
+class TestParseSynack:
+
+    def test_linux_64_ttl(self):
+        resp = _make_synack(ttl=64)
+        result = _parse_synack(resp)
+        assert result["ttl"] == 64
+
+    def test_windows_128_ttl(self):
+        resp = _make_synack(ttl=128)
+        result = _parse_synack(resp)
+        assert result["ttl"] == 128
+
+    def test_df_bit_set(self):
+        resp = _make_synack(flags=0x02)  # DF set
+        result = _parse_synack(resp)
+        assert result["df_bit"] == 1
+
+    def test_df_bit_unset(self):
+        resp = _make_synack(flags=0x00)
+        result = _parse_synack(resp)
+        assert result["df_bit"] == 0
+
+    def test_window_size(self):
+        resp = _make_synack(window=29200)
+        result = _parse_synack(resp)
+        assert result["window_size"] == 29200
+
+    def test_mss_extraction(self):
+        resp = _make_synack(options=[("MSS", 1460)])
+        result = _parse_synack(resp)
+        assert result["mss"] == 1460
+
+    def test_window_scale(self):
+        resp = _make_synack(options=[("WScale", 7)])
+        result = _parse_synack(resp)
+        assert result["window_scale"] == 7
+
+    def test_sack_ok(self):
+        resp = _make_synack(options=[("SAckOK", b"")])
+        result = _parse_synack(resp)
+        assert result["sack_ok"] == 1
+
+    def test_no_sack(self):
+        resp = _make_synack(options=[("MSS", 1460)])
+        result = _parse_synack(resp)
+        assert result["sack_ok"] == 0
+
+    def test_timestamp_present(self):
+        resp = _make_synack(options=[("Timestamp", (12345, 0))])
+        result = _parse_synack(resp)
+        assert result["timestamp"] == 1
+
+    def test_no_timestamp(self):
+        resp = _make_synack(options=[("MSS", 1460)])
+        result = _parse_synack(resp)
+        assert result["timestamp"] == 0
+
+    def test_options_order(self):
+        resp = _make_synack(options=[
+            ("MSS", 1460), ("NOP", None), ("WScale", 7),
+            ("SAckOK", b""), ("Timestamp", (0, 0)),
+        ])
+        result = _parse_synack(resp)
+        assert result["options_order"] == "M,N,W,S,T"
+
+    def test_ip_id(self):
+        resp = _make_synack(ip_id=12345)
+        result = _parse_synack(resp)
+        assert result["ip_id"] == 12345
+
+    def test_empty_options(self):
+        resp = _make_synack(options=[])
+        result = _parse_synack(resp)
+        assert result["mss"] == 0
+        assert result["window_scale"] == -1
+        assert result["sack_ok"] == 0
+        assert result["timestamp"] == 0
+        assert result["options_order"] == ""
+
+    def test_full_linux_fingerprint(self):
+        """Typical Linux 5.x+ SYN-ACK."""
+        resp = _make_synack(
+            ttl=64, flags=0x02, window=65535,
+            options=[
+                ("MSS", 1460), ("NOP", None), ("WScale", 7),
+                ("NOP", None), ("NOP", None), ("Timestamp", (0, 0)),
+                ("SAckOK", b""), ("EOL", None),
+            ],
+        )
+        result = _parse_synack(resp)
+        assert result["ttl"] == 64
+        assert result["df_bit"] == 1
+        assert result["window_size"] == 65535
+        assert result["mss"] == 1460
+        assert result["window_scale"] == 7
+        assert result["sack_ok"] == 1
+        assert result["timestamp"] == 1
+        assert result["options_order"] == "M,N,W,N,N,T,S,E"
+
+
+# ─── _compute_fingerprint ──────────────────────────────────────────────────
+
+class TestComputeFingerprint:
+
+    def test_hash_length_is_32(self):
+        fields = {
+            "ttl": 64, "window_size": 65535, "df_bit": 1,
+            "mss": 1460, "window_scale": 7, "sack_ok": 1,
+            "timestamp": 1, "options_order": "M,N,W,N,N,T,S,E",
+        }
+        raw, h = _compute_fingerprint(fields)
+        assert len(h) == 32
+
+    def test_deterministic(self):
+        fields = {
+            "ttl": 64, "window_size": 65535, "df_bit": 1,
+            "mss": 1460, "window_scale": 7, "sack_ok": 1,
+            "timestamp": 1, "options_order": "M,N,W,S,T",
+        }
+        _, h1 = _compute_fingerprint(fields)
+        _, h2 = _compute_fingerprint(fields)
+        assert h1 == h2
+
+    def test_different_inputs_different_hashes(self):
+        f1 = {
+            "ttl": 64, "window_size": 65535, "df_bit": 1,
+            "mss": 1460, "window_scale": 7, "sack_ok": 1,
+            "timestamp": 1, "options_order": "M,N,W,S,T",
+        }
+        f2 = {
+            "ttl": 128, "window_size": 8192, "df_bit": 1,
+            "mss": 1460, "window_scale": 8, "sack_ok": 1,
+            "timestamp": 0, "options_order": "M,N,W,N,N,S",
+        }
+        _, h1 = _compute_fingerprint(f1)
+        _, h2 = _compute_fingerprint(f2)
+        assert h1 != h2
+
+    def test_raw_format(self):
+        fields = {
+            "ttl": 64, "window_size": 65535, "df_bit": 1,
+            "mss": 1460, "window_scale": 7, "sack_ok": 1,
+            "timestamp": 1, "options_order": "M,N,W",
+        }
+        raw, _ = _compute_fingerprint(fields)
+        assert raw == "64:65535:1:1460:7:1:1:M,N,W"
+
+    def test_sha256_correctness(self):
+        fields = {
+            "ttl": 64, "window_size": 65535, "df_bit": 1,
+            "mss": 1460, "window_scale": 7, "sack_ok": 1,
+            "timestamp": 1, "options_order": "M,N,W",
+        }
+        raw, h = _compute_fingerprint(fields)
+        expected = hashlib.sha256(raw.encode("utf-8")).hexdigest()[:32]
+        assert h == expected
+
+
+# ─── tcp_fingerprint (end-to-end with mocked scapy) ────────────────────────
+
+class TestTcpFingerprintE2E:
+
+    @patch("decnet.prober.tcpfp._send_syn")
+    def test_success(self, mock_send: MagicMock):
+        mock_send.return_value = _make_synack(
+            ttl=64, flags=0x02, window=65535,
+            options=[
+                ("MSS", 1460), ("NOP", None), ("WScale", 7),
+                ("SAckOK", b""), ("Timestamp", (0, 0)),
+            ],
+        )
+        result = tcp_fingerprint("10.0.0.1", 443, timeout=1.0)
+        assert result is not None
+        assert len(result["tcpfp_hash"]) == 32
+        assert result["ttl"] == 64
+        assert result["window_size"] == 65535
+        assert result["df_bit"] == 1
+        assert result["mss"] == 1460
+        assert result["window_scale"] == 7
+        assert result["sack_ok"] == 1
+        assert result["timestamp"] == 1
+        assert result["options_order"] == "M,N,W,S,T"
+
+    @patch("decnet.prober.tcpfp._send_syn")
+    def test_no_response_returns_none(self, mock_send: MagicMock):
+        mock_send.return_value = None
+        assert tcp_fingerprint("10.0.0.1", 443, timeout=1.0) is None
+
+    @patch("decnet.prober.tcpfp._send_syn")
+    def test_windows_fingerprint(self, mock_send: MagicMock):
+        mock_send.return_value = _make_synack(
+            ttl=128, flags=0x02, window=8192,
+            options=[
+                ("MSS", 1460), ("NOP", None), ("WScale", 8),
+                ("NOP", None), ("NOP", None), ("SAckOK", b""),
+            ],
+        )
+        result = tcp_fingerprint("10.0.0.1", 443, timeout=1.0)
+        assert result is not None
+        assert result["ttl"] == 128
+        assert result["window_size"] == 8192
+        assert result["window_scale"] == 8
+
+    @patch("decnet.prober.tcpfp._send_syn")
+    def test_embedded_device_fingerprint(self, mock_send: MagicMock):
+        """Embedded devices often have TTL=255, small window, no options."""
+        mock_send.return_value = _make_synack(
+            ttl=255, flags=0x00, window=4096,
+            options=[("MSS", 536)],
+        )
+        result = tcp_fingerprint("10.0.0.1", 80, timeout=1.0)
+        assert result is not None
+        assert result["ttl"] == 255
+        assert result["df_bit"] == 0
+        assert result["window_size"] == 4096
+        assert result["mss"] == 536
+        assert result["window_scale"] == -1
+        assert result["sack_ok"] == 0
+
+    @patch("decnet.prober.tcpfp._send_syn")
+    def test_result_contains_raw_and_hash(self, mock_send: MagicMock):
+        mock_send.return_value = _make_synack()
+        result = tcp_fingerprint("10.0.0.1", 443)
+        assert "tcpfp_hash" in result
+        assert "tcpfp_raw" in result
+        assert ":" in result["tcpfp_raw"]
+
+    @patch("decnet.prober.tcpfp._send_syn")
+    def test_deterministic(self, mock_send: MagicMock):
+        pkt = _make_synack(ttl=64, window=65535)
+        mock_send.return_value = pkt
+
+        r1 = tcp_fingerprint("10.0.0.1", 443)
+        r2 = tcp_fingerprint("10.0.0.1", 443)
+        assert r1["tcpfp_hash"] == r2["tcpfp_hash"]
+        assert r1["tcpfp_raw"] == r2["tcpfp_raw"]
--- a/tests/test_prober_worker.py
+++ b/tests/test_prober_worker.py
@@ -1,6 +1,6 @@
 """
 Tests for the prober worker — target discovery from the log stream and
-probe cycle behavior.
+probe cycle behavior (JARM, HASSH, TCP/IP fingerprinting).
 """

 from __future__ import annotations
@@ -14,6 +14,8 @@ import pytest
 from decnet.prober.jarm import JARM_EMPTY_HASH
 from decnet.prober.worker import (
    DEFAULT_PROBE_PORTS,
+    DEFAULT_SSH_PORTS,
+    DEFAULT_TCPFP_PORTS,
    _discover_attackers,
    _probe_cycle,
    _write_event,
@@ -103,86 +105,357 @@ class TestDiscoverAttackers:
        assert "10.0.0.1" in ips


-# ─── _probe_cycle ────────────────────────────────────────────────────────────
+# ─── _probe_cycle: JARM phase ──────────────────────────────────────────────

-class TestProbeCycle:
+class TestProbeCycleJARM:

+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
    @patch("decnet.prober.worker.jarm_hash")
-    def test_probes_new_ips(self, mock_jarm: MagicMock, tmp_path: Path):
+    def test_probes_new_ips(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                            mock_tcpfp: MagicMock, tmp_path: Path):
        mock_jarm.return_value = "c0c" * 10 + "a" * 32  # fake 62-char hash
+        mock_hassh.return_value = None
+        mock_tcpfp.return_value = None
        log_path = tmp_path / "decnet.log"
        json_path = tmp_path / "decnet.json"

        targets = {"10.0.0.1"}
-        probed: dict[str, set[int]] = {}
+        probed: dict[str, dict[str, set[int]]] = {}

-        _probe_cycle(targets, probed, [443, 8443], log_path, json_path, timeout=1.0)
+        _probe_cycle(targets, probed, [443, 8443], [], [], log_path, json_path, timeout=1.0)

        assert mock_jarm.call_count == 2  # two ports
-        assert 443 in probed["10.0.0.1"]
-        assert 8443 in probed["10.0.0.1"]
+        assert 443 in probed["10.0.0.1"]["jarm"]
+        assert 8443 in probed["10.0.0.1"]["jarm"]

+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
    @patch("decnet.prober.worker.jarm_hash")
-    def test_skips_already_probed_ports(self, mock_jarm: MagicMock, tmp_path: Path):
+    def test_skips_already_probed_ports(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                        mock_tcpfp: MagicMock, tmp_path: Path):
        mock_jarm.return_value = "c0c" * 10 + "a" * 32
+        mock_hassh.return_value = None
+        mock_tcpfp.return_value = None
        log_path = tmp_path / "decnet.log"
        json_path = tmp_path / "decnet.json"

        targets = {"10.0.0.1"}
-        probed: dict[str, set[int]] = {"10.0.0.1": {443}}
+        probed: dict[str, dict[str, set[int]]] = {"10.0.0.1": {"jarm": {443}}}

-        _probe_cycle(targets, probed, [443, 8443], log_path, json_path, timeout=1.0)
+        _probe_cycle(targets, probed, [443, 8443], [], [], log_path, json_path, timeout=1.0)

        # Should only probe 8443 (443 already done)
        assert mock_jarm.call_count == 1
        mock_jarm.assert_called_once_with("10.0.0.1", 8443, timeout=1.0)

+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
    @patch("decnet.prober.worker.jarm_hash")
-    def test_empty_hash_not_logged(self, mock_jarm: MagicMock, tmp_path: Path):
-        """All-zeros JARM hash (no TLS server) should not be written as a jarm_fingerprint event."""
+    def test_empty_hash_not_logged(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                    mock_tcpfp: MagicMock, tmp_path: Path):
        mock_jarm.return_value = JARM_EMPTY_HASH
+        mock_hassh.return_value = None
+        mock_tcpfp.return_value = None
        log_path = tmp_path / "decnet.log"
        json_path = tmp_path / "decnet.json"

        targets = {"10.0.0.1"}
-        probed: dict[str, set[int]] = {}
+        probed: dict[str, dict[str, set[int]]] = {}

-        _probe_cycle(targets, probed, [443], log_path, json_path, timeout=1.0)
+        _probe_cycle(targets, probed, [443], [], [], log_path, json_path, timeout=1.0)

-        # Port should be marked as probed
-        assert 443 in probed["10.0.0.1"]
-        # But no jarm_fingerprint event should be written
+        assert 443 in probed["10.0.0.1"]["jarm"]
        if json_path.exists():
            content = json_path.read_text()
            assert "jarm_fingerprint" not in content

+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
    @patch("decnet.prober.worker.jarm_hash")
-    def test_exception_marks_port_probed(self, mock_jarm: MagicMock, tmp_path: Path):
+    def test_exception_marks_port_probed(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                          mock_tcpfp: MagicMock, tmp_path: Path):
        mock_jarm.side_effect = OSError("Connection refused")
+        mock_hassh.return_value = None
+        mock_tcpfp.return_value = None
        log_path = tmp_path / "decnet.log"
        json_path = tmp_path / "decnet.json"

        targets = {"10.0.0.1"}
-        probed: dict[str, set[int]] = {}
+        probed: dict[str, dict[str, set[int]]] = {}

-        _probe_cycle(targets, probed, [443], log_path, json_path, timeout=1.0)
+        _probe_cycle(targets, probed, [443], [], [], log_path, json_path, timeout=1.0)

-        # Port marked as probed to avoid infinite retries
-        assert 443 in probed["10.0.0.1"]
+        assert 443 in probed["10.0.0.1"]["jarm"]

+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
    @patch("decnet.prober.worker.jarm_hash")
-    def test_skips_ip_with_all_ports_done(self, mock_jarm: MagicMock, tmp_path: Path):
+    def test_skips_ip_with_all_ports_done(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                           mock_tcpfp: MagicMock, tmp_path: Path):
        log_path = tmp_path / "decnet.log"
        json_path = tmp_path / "decnet.json"

        targets = {"10.0.0.1"}
-        probed: dict[str, set[int]] = {"10.0.0.1": {443, 8443}}
+        probed: dict[str, dict[str, set[int]]] = {
+            "10.0.0.1": {"jarm": {443, 8443}, "hassh": set(), "tcpfp": set()},
+        }

-        _probe_cycle(targets, probed, [443, 8443], log_path, json_path, timeout=1.0)
+        _probe_cycle(targets, probed, [443, 8443], [], [], log_path, json_path, timeout=1.0)

        assert mock_jarm.call_count == 0


+# ─── _probe_cycle: HASSH phase ─────────────────────────────────────────────
+
+class TestProbeCycleHASSH:
+
+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
+    @patch("decnet.prober.worker.jarm_hash")
+    def test_probes_ssh_ports(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                               mock_tcpfp: MagicMock, tmp_path: Path):
+        mock_jarm.return_value = JARM_EMPTY_HASH
+        mock_hassh.return_value = {
+            "hassh_server": "a" * 32,
+            "banner": "SSH-2.0-OpenSSH_8.9p1",
+            "kex_algorithms": "curve25519-sha256",
+            "encryption_s2c": "aes256-gcm@openssh.com",
+            "mac_s2c": "hmac-sha2-256-etm@openssh.com",
+            "compression_s2c": "none",
+        }
+        mock_tcpfp.return_value = None
+        log_path = tmp_path / "decnet.log"
+        json_path = tmp_path / "decnet.json"
+
+        targets = {"10.0.0.1"}
+        probed: dict[str, dict[str, set[int]]] = {}
+
+        _probe_cycle(targets, probed, [], [22, 2222], [], log_path, json_path, timeout=1.0)
+
+        assert mock_hassh.call_count == 2
+        assert 22 in probed["10.0.0.1"]["hassh"]
+        assert 2222 in probed["10.0.0.1"]["hassh"]
+
+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
+    @patch("decnet.prober.worker.jarm_hash")
+    def test_hassh_writes_event(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                 mock_tcpfp: MagicMock, tmp_path: Path):
+        mock_jarm.return_value = JARM_EMPTY_HASH
+        mock_hassh.return_value = {
+            "hassh_server": "b" * 32,
+            "banner": "SSH-2.0-Paramiko_3.0",
+            "kex_algorithms": "diffie-hellman-group14-sha1",
+            "encryption_s2c": "aes128-cbc",
+            "mac_s2c": "hmac-sha1",
+            "compression_s2c": "none",
+        }
+        mock_tcpfp.return_value = None
+        log_path = tmp_path / "decnet.log"
+        json_path = tmp_path / "decnet.json"
+
+        targets = {"10.0.0.1"}
+        probed: dict[str, dict[str, set[int]]] = {}
+
+        _probe_cycle(targets, probed, [], [22], [], log_path, json_path, timeout=1.0)
+
+        assert json_path.exists()
+        content = json_path.read_text()
+        assert "hassh_fingerprint" in content
+        record = json.loads(content.strip())
+        assert record["fields"]["hassh_server_hash"] == "b" * 32
+        assert record["fields"]["ssh_banner"] == "SSH-2.0-Paramiko_3.0"
+
+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
+    @patch("decnet.prober.worker.jarm_hash")
+    def test_hassh_none_not_logged(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                    mock_tcpfp: MagicMock, tmp_path: Path):
+        mock_jarm.return_value = JARM_EMPTY_HASH
+        mock_hassh.return_value = None  # No SSH server
+        mock_tcpfp.return_value = None
+        log_path = tmp_path / "decnet.log"
+        json_path = tmp_path / "decnet.json"
+
+        targets = {"10.0.0.1"}
+        probed: dict[str, dict[str, set[int]]] = {}
+
+        _probe_cycle(targets, probed, [], [22], [], log_path, json_path, timeout=1.0)
+
+        assert 22 in probed["10.0.0.1"]["hassh"]
+        if json_path.exists():
+            content = json_path.read_text()
+            assert "hassh_fingerprint" not in content
+
+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
+    @patch("decnet.prober.worker.jarm_hash")
+    def test_hassh_skips_already_probed(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                         mock_tcpfp: MagicMock, tmp_path: Path):
+        mock_jarm.return_value = JARM_EMPTY_HASH
+        mock_tcpfp.return_value = None
+        log_path = tmp_path / "decnet.log"
+        json_path = tmp_path / "decnet.json"
+
+        targets = {"10.0.0.1"}
+        probed: dict[str, dict[str, set[int]]] = {"10.0.0.1": {"hassh": {22}}}
+
+        _probe_cycle(targets, probed, [], [22, 2222], [], log_path, json_path, timeout=1.0)
+
+        assert mock_hassh.call_count == 1  # only 2222
+        mock_hassh.assert_called_once_with("10.0.0.1", 2222, timeout=1.0)
+
+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
+    @patch("decnet.prober.worker.jarm_hash")
+    def test_hassh_exception_marks_probed(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                           mock_tcpfp: MagicMock, tmp_path: Path):
+        mock_jarm.return_value = JARM_EMPTY_HASH
+        mock_hassh.side_effect = OSError("Connection refused")
+        mock_tcpfp.return_value = None
+        log_path = tmp_path / "decnet.log"
+        json_path = tmp_path / "decnet.json"
+
+        targets = {"10.0.0.1"}
+        probed: dict[str, dict[str, set[int]]] = {}
+
+        _probe_cycle(targets, probed, [], [22], [], log_path, json_path, timeout=1.0)
+
+        assert 22 in probed["10.0.0.1"]["hassh"]
+
+
+# ─── _probe_cycle: TCPFP phase ─────────────────────────────────────────────
+
+class TestProbeCycleTCPFP:
+
+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
+    @patch("decnet.prober.worker.jarm_hash")
+    def test_probes_tcpfp_ports(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                 mock_tcpfp: MagicMock, tmp_path: Path):
+        mock_jarm.return_value = JARM_EMPTY_HASH
+        mock_hassh.return_value = None
+        mock_tcpfp.return_value = {
+            "tcpfp_hash": "d" * 32,
+            "tcpfp_raw": "64:65535:1:1460:7:1:1:M,N,W,N,N,T,S,E",
+            "ttl": 64, "window_size": 65535, "df_bit": 1,
+            "mss": 1460, "window_scale": 7, "sack_ok": 1,
+            "timestamp": 1, "options_order": "M,N,W,N,N,T,S,E",
+        }
+        log_path = tmp_path / "decnet.log"
+        json_path = tmp_path / "decnet.json"
+
+        targets = {"10.0.0.1"}
+        probed: dict[str, dict[str, set[int]]] = {}
+
+        _probe_cycle(targets, probed, [], [], [80, 443], log_path, json_path, timeout=1.0)
+
+        assert mock_tcpfp.call_count == 2
+        assert 80 in probed["10.0.0.1"]["tcpfp"]
+        assert 443 in probed["10.0.0.1"]["tcpfp"]
+
+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
+    @patch("decnet.prober.worker.jarm_hash")
+    def test_tcpfp_writes_event_with_all_fields(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                                  mock_tcpfp: MagicMock, tmp_path: Path):
+        mock_jarm.return_value = JARM_EMPTY_HASH
+        mock_hassh.return_value = None
+        mock_tcpfp.return_value = {
+            "tcpfp_hash": "e" * 32,
+            "tcpfp_raw": "128:8192:1:1460:8:1:0:M,N,W,N,N,S",
+            "ttl": 128, "window_size": 8192, "df_bit": 1,
+            "mss": 1460, "window_scale": 8, "sack_ok": 1,
+            "timestamp": 0, "options_order": "M,N,W,N,N,S",
+        }
+        log_path = tmp_path / "decnet.log"
+        json_path = tmp_path / "decnet.json"
+
+        targets = {"10.0.0.1"}
+        probed: dict[str, dict[str, set[int]]] = {}
+
+        _probe_cycle(targets, probed, [], [], [443], log_path, json_path, timeout=1.0)
+
+        content = json_path.read_text()
+        assert "tcpfp_fingerprint" in content
+        record = json.loads(content.strip())
+        assert record["fields"]["tcpfp_hash"] == "e" * 32
+        assert record["fields"]["ttl"] == "128"
+        assert record["fields"]["window_size"] == "8192"
+        assert record["fields"]["options_order"] == "M,N,W,N,N,S"
+
+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
+    @patch("decnet.prober.worker.jarm_hash")
+    def test_tcpfp_none_not_logged(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                    mock_tcpfp: MagicMock, tmp_path: Path):
+        mock_jarm.return_value = JARM_EMPTY_HASH
+        mock_hassh.return_value = None
+        mock_tcpfp.return_value = None
+        log_path = tmp_path / "decnet.log"
+        json_path = tmp_path / "decnet.json"
+
+        targets = {"10.0.0.1"}
+        probed: dict[str, dict[str, set[int]]] = {}
+
+        _probe_cycle(targets, probed, [], [], [443], log_path, json_path, timeout=1.0)
+
+        assert 443 in probed["10.0.0.1"]["tcpfp"]
+        if json_path.exists():
+            content = json_path.read_text()
+            assert "tcpfp_fingerprint" not in content
+
+
+# ─── Probe type isolation ───────────────────────────────────────────────────
+
+class TestProbeTypeIsolation:
+
+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
+    @patch("decnet.prober.worker.jarm_hash")
+    def test_jarm_does_not_mark_hassh(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                       mock_tcpfp: MagicMock, tmp_path: Path):
+        """JARM probing port 2222 should not mark HASSH port 2222 as done."""
+        mock_jarm.return_value = JARM_EMPTY_HASH
+        mock_hassh.return_value = None
+        mock_tcpfp.return_value = None
+        log_path = tmp_path / "decnet.log"
+        json_path = tmp_path / "decnet.json"
+
+        targets = {"10.0.0.1"}
+        probed: dict[str, dict[str, set[int]]] = {}
+
+        # Probe with JARM on 2222 and HASSH on 2222
+        _probe_cycle(targets, probed, [2222], [2222], [], log_path, json_path, timeout=1.0)
+
+        # Both should be called
+        assert mock_jarm.call_count == 1
+        assert mock_hassh.call_count == 1
+        assert 2222 in probed["10.0.0.1"]["jarm"]
+        assert 2222 in probed["10.0.0.1"]["hassh"]
+
+    @patch("decnet.prober.worker.tcp_fingerprint")
+    @patch("decnet.prober.worker.hassh_server")
+    @patch("decnet.prober.worker.jarm_hash")
+    def test_all_three_probes_run(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
+                                   mock_tcpfp: MagicMock, tmp_path: Path):
+        mock_jarm.return_value = JARM_EMPTY_HASH
+        mock_hassh.return_value = None
+        mock_tcpfp.return_value = None
+        log_path = tmp_path / "decnet.log"
+        json_path = tmp_path / "decnet.json"
+
+        targets = {"10.0.0.1"}
+        probed: dict[str, dict[str, set[int]]] = {}
+
+        _probe_cycle(targets, probed, [443], [22], [80], log_path, json_path, timeout=1.0)
+
+        assert mock_jarm.call_count == 1
+        assert mock_hassh.call_count == 1
+        assert mock_tcpfp.call_count == 1
+
+
 # ─── _write_event ────────────────────────────────────────────────────────────

 class TestWriteEvent: