feat(prober): add IcmpErrorProbe — ICMP error-leakage fingerprint

Sends four crafted stimuli (UDP/closed-port, TTL=1, DF+oversized,
bad IP option) and records which ICMP error classes come back, the
per-error RTT, and the bytes echoed in each ICMP body. Absence is
as informative as a reply — Linux rate-limiting is a fingerprint signal.

Returns None when no packets could be sent (no CAP_NET_RAW), so the
probe is a no-op in non-root test environments. Port-free ActiveProbe
subclass (priority=850), metaclass auto-registered in the registry.

Also fixes three sets of stale tests left over from the TlsCertProbe
migration (4b2759e0):
- test_active_probe_registry: closed name/order sets updated for
  tls_certificate and icmp_error
- test_prober_rotation: dead patches on worker.fetch_leaf_cert removed
- test_prober_worker (TestProbeCycleTLSCert): rewritten to test
  TlsCertProbe as an independent registry probe, patch target updated
  from worker.fetch_leaf_cert to probes.tlscert_probe.fetch_leaf_cert
This commit is contained in:
2026-05-21 14:52:49 -04:00
parent 4b2759e0fc
commit 56229a272b
7 changed files with 781 additions and 84 deletions

View File

@@ -110,13 +110,11 @@ class TestDiscoverAttackers:
class TestProbeCycleJARM:
@patch("decnet.prober.ipv6_leak._route_info", return_value=(False, None))
@patch("decnet.prober.worker.fetch_leaf_cert", return_value=None)
@patch("decnet.prober.probes.tcpfp.tcp_fingerprint")
@patch("decnet.prober.probes.hassh.hassh_server")
@patch("decnet.prober.probes.jarm.jarm_hash")
def test_probes_new_ips(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
mock_tcpfp: MagicMock, mock_cert: MagicMock,
mock_ipv6: MagicMock,
mock_tcpfp: MagicMock, mock_ipv6: MagicMock,
tmp_path: Path, monkeypatch: pytest.MonkeyPatch):
monkeypatch.setattr(JarmProbe, "default_ports", [443, 8443])
monkeypatch.setattr(HasshProbe, "default_ports", [])
@@ -137,13 +135,11 @@ class TestProbeCycleJARM:
assert 8443 in probed["10.0.0.1"]["jarm"]
@patch("decnet.prober.ipv6_leak._route_info", return_value=(False, None))
@patch("decnet.prober.worker.fetch_leaf_cert", return_value=None)
@patch("decnet.prober.probes.tcpfp.tcp_fingerprint")
@patch("decnet.prober.probes.hassh.hassh_server")
@patch("decnet.prober.probes.jarm.jarm_hash")
def test_skips_already_probed_ports(self, mock_jarm: MagicMock, mock_hassh: MagicMock,
mock_tcpfp: MagicMock, mock_cert: MagicMock,
mock_ipv6: MagicMock,
mock_tcpfp: MagicMock, mock_ipv6: MagicMock,
tmp_path: Path, monkeypatch: pytest.MonkeyPatch):
monkeypatch.setattr(JarmProbe, "default_ports", [443, 8443])
monkeypatch.setattr(HasshProbe, "default_ports", [])
@@ -560,16 +556,29 @@ class TestWriteEvent:
assert record["fields"]["target_ip"] == "10.0.0.1"
# ─── _probe_cycle: TLS certificate capture (after JARM) ───────────────────
# ─── _probe_cycle: TLS certificate capture ────────────────────────────────
# TlsCertProbe is now an independent registered probe (priority=200).
# It calls fetch_leaf_cert directly — not coupled to JARM outcome.
_CERT_STUB = {
"subject_cn": "evil.example.com",
"issuer": "CN=evil.example.com",
"self_signed": True,
"not_before": "2026-01-01T00:00:00Z",
"not_after": "2027-01-01T00:00:00Z",
"sans": ["evil.example.com", "c2.example.com"],
"cert_sha256": "ab" * 32,
}
class TestProbeCycleTLSCert:
@patch("decnet.prober.ipv6_leak._route_info", return_value=(False, None))
@patch("decnet.prober.worker.fetch_leaf_cert")
@patch("decnet.prober.probes.tlscert_probe.fetch_leaf_cert")
@patch("decnet.prober.probes.tcpfp.tcp_fingerprint")
@patch("decnet.prober.probes.hassh.hassh_server")
@patch("decnet.prober.probes.jarm.jarm_hash")
def test_cert_event_emitted_after_successful_jarm(
def test_cert_event_emitted_for_tls_port(
self,
mock_jarm: MagicMock,
mock_hassh: MagicMock,
@@ -579,52 +588,39 @@ class TestProbeCycleTLSCert:
tmp_path: Path,
monkeypatch: pytest.MonkeyPatch,
):
"""A non-empty JARM hash should trigger a follow-up cert fetch and
write a tls_certificate event with all parsed fields."""
monkeypatch.setattr(JarmProbe, "default_ports", [443])
"""TlsCertProbe runs independently; a successful fetch writes a tls_certificate event."""
from decnet.prober.probes.tlscert_probe import TlsCertProbe
monkeypatch.setattr(JarmProbe, "default_ports", [])
monkeypatch.setattr(HasshProbe, "default_ports", [])
monkeypatch.setattr(TcpfpProbe, "default_ports", [])
mock_jarm.return_value = "c0c" * 10 + "a" * 32
monkeypatch.setattr(TlsCertProbe, "default_ports", [443])
mock_jarm.return_value = JARM_EMPTY_HASH
mock_hassh.return_value = None
mock_tcpfp.return_value = None
mock_cert.return_value = {
"subject_cn": "evil.example.com",
"issuer": "CN=evil.example.com",
"self_signed": True,
"not_before": "2026-01-01T00:00:00Z",
"not_after": "2027-01-01T00:00:00Z",
"sans": ["evil.example.com", "c2.example.com"],
"cert_sha256": "ab" * 32,
}
mock_cert.return_value = _CERT_STUB
log_path = tmp_path / "decnet.log"
json_path = tmp_path / "decnet.json"
_probe_cycle({"10.0.0.1"}, {}, log_path, json_path, timeout=1.0)
mock_cert.assert_called_once_with("10.0.0.1", 443, timeout=1.0)
records = [
json.loads(line)
for line in json_path.read_text().splitlines() if line
]
records = [json.loads(line) for line in json_path.read_text().splitlines() if line]
cert_records = [r for r in records if r["event_type"] == "tls_certificate"]
assert len(cert_records) == 1
f = cert_records[0]["fields"]
assert f["target_ip"] == "10.0.0.1"
assert f["target_port"] == "443"
assert f["subject_cn"] == "evil.example.com"
assert f["issuer"] == "CN=evil.example.com"
assert f["self_signed"] == "true"
assert f["not_before"] == "2026-01-01T00:00:00Z"
assert f["not_after"] == "2027-01-01T00:00:00Z"
assert f["sans"] == "evil.example.com,c2.example.com"
assert f["cert_sha256"] == "ab" * 32
@patch("decnet.prober.ipv6_leak._route_info", return_value=(False, None))
@patch("decnet.prober.worker.fetch_leaf_cert")
@patch("decnet.prober.probes.tlscert_probe.fetch_leaf_cert", return_value=None)
@patch("decnet.prober.probes.tcpfp.tcp_fingerprint")
@patch("decnet.prober.probes.hassh.hassh_server")
@patch("decnet.prober.probes.jarm.jarm_hash")
def test_cert_fetch_skipped_on_empty_jarm(
def test_cert_skipped_when_fetch_returns_none(
self,
mock_jarm: MagicMock,
mock_hassh: MagicMock,
@@ -634,10 +630,12 @@ class TestProbeCycleTLSCert:
tmp_path: Path,
monkeypatch: pytest.MonkeyPatch,
):
"""JARM_EMPTY_HASH means the port doesn't speak TLS; skip cert fetch."""
monkeypatch.setattr(JarmProbe, "default_ports", [443])
"""fetch_leaf_cert returning None → no tls_certificate event."""
from decnet.prober.probes.tlscert_probe import TlsCertProbe
monkeypatch.setattr(JarmProbe, "default_ports", [])
monkeypatch.setattr(HasshProbe, "default_ports", [])
monkeypatch.setattr(TcpfpProbe, "default_ports", [])
monkeypatch.setattr(TlsCertProbe, "default_ports", [443])
mock_jarm.return_value = JARM_EMPTY_HASH
mock_hassh.return_value = None
mock_tcpfp.return_value = None
@@ -646,42 +644,13 @@ class TestProbeCycleTLSCert:
_probe_cycle({"10.0.0.1"}, {}, log_path, json_path, timeout=1.0)
mock_cert.assert_not_called()
@patch("decnet.prober.ipv6_leak._route_info", return_value=(False, None))
@patch("decnet.prober.worker.fetch_leaf_cert", return_value=None)
@patch("decnet.prober.probes.tcpfp.tcp_fingerprint")
@patch("decnet.prober.probes.hassh.hassh_server")
@patch("decnet.prober.probes.jarm.jarm_hash")
def test_cert_fetch_failure_silent(
self,
mock_jarm: MagicMock,
mock_hassh: MagicMock,
mock_tcpfp: MagicMock,
mock_cert: MagicMock,
mock_ipv6: MagicMock,
tmp_path: Path,
monkeypatch: pytest.MonkeyPatch,
):
"""fetch_leaf_cert returning None must not write a cert event."""
monkeypatch.setattr(JarmProbe, "default_ports", [443])
monkeypatch.setattr(HasshProbe, "default_ports", [])
monkeypatch.setattr(TcpfpProbe, "default_ports", [])
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"
_probe_cycle({"10.0.0.1"}, {}, log_path, json_path, timeout=1.0)
mock_cert.assert_called_once_with("10.0.0.1", 443, timeout=1.0)
if json_path.exists():
content = json_path.read_text()
assert "tls_certificate" not in content
@patch("decnet.prober.ipv6_leak._route_info", return_value=(False, None))
@patch("decnet.prober.worker.fetch_leaf_cert")
@patch("decnet.prober.probes.tlscert_probe.fetch_leaf_cert")
@patch("decnet.prober.probes.tcpfp.tcp_fingerprint")
@patch("decnet.prober.probes.hassh.hassh_server")
@patch("decnet.prober.probes.jarm.jarm_hash")
@@ -695,12 +664,13 @@ class TestProbeCycleTLSCert:
tmp_path: Path,
monkeypatch: pytest.MonkeyPatch,
):
"""If fetch_leaf_cert throws despite its contract, the JARM phase
must keep moving to the next port without crashing."""
monkeypatch.setattr(JarmProbe, "default_ports", [443, 8443])
"""fetch_leaf_cert crash is caught by _run_probe; both ports still marked probed."""
from decnet.prober.probes.tlscert_probe import TlsCertProbe
monkeypatch.setattr(JarmProbe, "default_ports", [])
monkeypatch.setattr(HasshProbe, "default_ports", [])
monkeypatch.setattr(TcpfpProbe, "default_ports", [])
mock_jarm.return_value = "c0c" * 10 + "a" * 32
monkeypatch.setattr(TlsCertProbe, "default_ports", [443, 8443])
mock_jarm.return_value = JARM_EMPTY_HASH
mock_hassh.return_value = None
mock_tcpfp.return_value = None
mock_cert.side_effect = RuntimeError("unexpected")
@@ -709,11 +679,10 @@ class TestProbeCycleTLSCert:
_probe_cycle({"10.0.0.1"}, {}, log_path, json_path, timeout=1.0)
# Both ports still marked probed despite the cert-side crash.
assert mock_cert.call_count == 2
@patch("decnet.prober.ipv6_leak._route_info", return_value=(False, None))
@patch("decnet.prober.worker.fetch_leaf_cert")
@patch("decnet.prober.probes.tlscert_probe.fetch_leaf_cert")
@patch("decnet.prober.probes.tcpfp.tcp_fingerprint")
@patch("decnet.prober.probes.hassh.hassh_server")
@patch("decnet.prober.probes.jarm.jarm_hash")
@@ -727,11 +696,13 @@ class TestProbeCycleTLSCert:
tmp_path: Path,
monkeypatch: pytest.MonkeyPatch,
):
"""publish_fn must receive a 'tls_certificate' event when capture succeeds."""
monkeypatch.setattr(JarmProbe, "default_ports", [443])
"""publish_fn receives a 'tls_certificate' event on successful cert capture."""
from decnet.prober.probes.tlscert_probe import TlsCertProbe
monkeypatch.setattr(JarmProbe, "default_ports", [])
monkeypatch.setattr(HasshProbe, "default_ports", [])
monkeypatch.setattr(TcpfpProbe, "default_ports", [])
mock_jarm.return_value = "c0c" * 10 + "a" * 32
monkeypatch.setattr(TlsCertProbe, "default_ports", [443])
mock_jarm.return_value = JARM_EMPTY_HASH
mock_hassh.return_value = None
mock_tcpfp.return_value = None
mock_cert.return_value = {
@@ -760,3 +731,36 @@ class TestProbeCycleTLSCert:
assert cert_pubs[0][1]["port"] == 443
assert cert_pubs[0][1]["cert_sha256"] == "cd" * 32
assert cert_pubs[0][1]["self_signed"] is True
@patch("decnet.prober.ipv6_leak._route_info", return_value=(False, None))
@patch("decnet.prober.probes.tlscert_probe.fetch_leaf_cert")
@patch("decnet.prober.probes.tcpfp.tcp_fingerprint")
@patch("decnet.prober.probes.hassh.hassh_server")
@patch("decnet.prober.probes.jarm.jarm_hash")
def test_cert_independent_of_jarm_result(
self,
mock_jarm: MagicMock,
mock_hassh: MagicMock,
mock_tcpfp: MagicMock,
mock_cert: MagicMock,
mock_ipv6: MagicMock,
tmp_path: Path,
monkeypatch: pytest.MonkeyPatch,
):
"""TlsCertProbe runs regardless of JARM outcome (independent registry probe)."""
from decnet.prober.probes.tlscert_probe import TlsCertProbe
monkeypatch.setattr(JarmProbe, "default_ports", [443])
monkeypatch.setattr(HasshProbe, "default_ports", [])
monkeypatch.setattr(TcpfpProbe, "default_ports", [])
monkeypatch.setattr(TlsCertProbe, "default_ports", [443])
mock_jarm.return_value = JARM_EMPTY_HASH # port doesn't speak TLS per JARM
mock_hassh.return_value = None
mock_tcpfp.return_value = None
mock_cert.return_value = _CERT_STUB
log_path = tmp_path / "decnet.log"
json_path = tmp_path / "decnet.json"
_probe_cycle({"10.0.0.1"}, {}, log_path, json_path, timeout=1.0)
# TlsCertProbe still called despite empty JARM hash
mock_cert.assert_called_once_with("10.0.0.1", 443, timeout=1.0)