347 lines
12 KiB
Python
347 lines
12 KiB
Python
"""STIX 2.1 bundle builder for a DECNET attacker observation.
|
|
|
|
Pure function — no I/O. The caller (router) does all DB reads and
|
|
passes dicts; this module assembles the STIX bundle.
|
|
|
|
SDO/SRO mapping
|
|
---------------
|
|
DECNET data → STIX type
|
|
----------- ---------
|
|
Producer (DECNET) → identity (org, deterministic ID)
|
|
attacker.ip → ipv4-addr SCO
|
|
first/last seen + count → observed-data SDO
|
|
AttackerIdentity or IP → threat-actor SDO
|
|
Per-technique rollup → attack-pattern SDO + relationship(uses) SRO
|
|
Per ttp_tag row → sighting SRO
|
|
ObservedAttachment / Log → file SCO + observed-data SDO
|
|
SmtpTarget → domain-name SCO + observed-data SDO
|
|
AttackerIntel verdict → note SDO
|
|
|
|
Attack-pattern SDOs carry the canonical MITRE STIX IDs pulled from the
|
|
loaded enterprise bundle so the objects are deduplicated against the
|
|
public ATT&CK bundle by any consumer that already has it.
|
|
"""
|
|
from __future__ import annotations
|
|
|
|
import json
|
|
import uuid as _uuid
|
|
from datetime import datetime, timezone
|
|
from typing import Any
|
|
|
|
import stix2
|
|
|
|
from decnet.ttp import attack_stix
|
|
|
|
# Deterministic DECNET org identity ID — stable across all bundles this
|
|
# instance produces. Consumers can correlate across exports.
|
|
_NS = _uuid.UUID("b5d2c3a1-8f4e-4d1b-9a6c-0e7f5b3d2c1a")
|
|
_DECNET_ORG_STIX_ID = f"identity--{_uuid.uuid5(_NS, 'decnet-honeypot')}"
|
|
|
|
|
|
def _aware(dt: datetime | str | None) -> datetime | None:
|
|
if dt is None:
|
|
return None
|
|
if isinstance(dt, str):
|
|
dt = datetime.fromisoformat(dt.replace("Z", "+00:00"))
|
|
if dt.tzinfo is None:
|
|
return dt.replace(tzinfo=timezone.utc)
|
|
return dt
|
|
|
|
|
|
def _decnet_org() -> stix2.Identity:
|
|
return stix2.Identity(
|
|
id=_DECNET_ORG_STIX_ID,
|
|
name="DECNET",
|
|
identity_class="organization",
|
|
description="DECNET honeypot platform — automated threat observation",
|
|
)
|
|
|
|
|
|
def _threat_actor(
|
|
attacker: dict[str, Any],
|
|
identity: dict[str, Any] | None,
|
|
created_by: str,
|
|
) -> stix2.ThreatActor:
|
|
if identity:
|
|
name = f"DECNET-identity-{identity['uuid'][:8]}"
|
|
else:
|
|
name = f"DECNET-attacker-{attacker['uuid'][:8]}"
|
|
kwargs: dict[str, Any] = dict(
|
|
id=f"threat-actor--{_uuid.uuid5(_NS, attacker['uuid'])}",
|
|
name=name,
|
|
threat_actor_types=["unknown"],
|
|
created_by_ref=created_by,
|
|
allow_custom=True,
|
|
)
|
|
if attacker.get("country_code"):
|
|
kwargs["x_decnet_country_code"] = attacker["country_code"]
|
|
if attacker.get("asn"):
|
|
kwargs["x_decnet_asn"] = attacker["asn"]
|
|
if attacker.get("as_name"):
|
|
kwargs["x_decnet_as_name"] = attacker["as_name"]
|
|
if identity:
|
|
if identity.get("ja3_hashes"):
|
|
kwargs["x_decnet_ja3_hashes"] = identity["ja3_hashes"]
|
|
if identity.get("hassh_hashes"):
|
|
kwargs["x_decnet_hassh_hashes"] = identity["hassh_hashes"]
|
|
if identity.get("c2_endpoints"):
|
|
kwargs["x_decnet_c2_endpoints"] = identity["c2_endpoints"]
|
|
return stix2.ThreatActor(**kwargs)
|
|
|
|
|
|
def _attack_pattern_sdo(technique_id: str, created_by: str) -> stix2.AttackPattern | None:
|
|
obj = attack_stix._attack_pattern_by_id(technique_id)
|
|
if obj is None:
|
|
return None
|
|
ext_refs = obj.get("external_references", [])
|
|
mitre_ref = next(
|
|
(r for r in ext_refs if r.get("source_name") == "mitre-attack"), None,
|
|
)
|
|
er_args = [
|
|
stix2.ExternalReference(
|
|
source_name="mitre-attack",
|
|
external_id=mitre_ref["external_id"],
|
|
url=mitre_ref.get("url", ""),
|
|
)
|
|
] if mitre_ref else []
|
|
return stix2.AttackPattern(
|
|
id=obj["id"],
|
|
name=obj.get("name", technique_id),
|
|
external_references=er_args,
|
|
created_by_ref=created_by,
|
|
)
|
|
|
|
|
|
def _intel_note(
|
|
intel: dict[str, Any],
|
|
ta_id: str,
|
|
created_by: str,
|
|
) -> stix2.Note | None:
|
|
verdict = intel.get("aggregate_verdict") or "unknown"
|
|
lines: list[str] = [f"aggregate_verdict: {verdict}"]
|
|
if intel.get("abuseipdb_score") is not None:
|
|
lines.append(f"abuseipdb_score: {intel['abuseipdb_score']}")
|
|
if intel.get("greynoise_classification"):
|
|
tags = intel.get("greynoise_tags") or []
|
|
if isinstance(tags, str):
|
|
try:
|
|
tags = json.loads(tags)
|
|
except Exception:
|
|
tags = []
|
|
lines.append(f"greynoise: {intel['greynoise_classification']} ({', '.join(tags)})")
|
|
if intel.get("feodo_listed"):
|
|
lines.append(f"feodo: {intel.get('feodo_malware_family', 'listed')}")
|
|
if intel.get("threatfox_listed"):
|
|
tt = intel.get("threatfox_threat_types") or []
|
|
if isinstance(tt, str):
|
|
try:
|
|
tt = json.loads(tt)
|
|
except Exception:
|
|
tt = []
|
|
lines.append(f"threatfox: {', '.join(tt) if tt else 'listed'}")
|
|
return stix2.Note(
|
|
abstract="DECNET threat-intel verdict",
|
|
content="\n".join(lines),
|
|
object_refs=[ta_id],
|
|
created_by_ref=created_by,
|
|
)
|
|
|
|
|
|
def build_attacker_bundle(
|
|
attacker: dict[str, Any],
|
|
behavior: dict[str, Any] | None,
|
|
identity: dict[str, Any] | None,
|
|
intel: dict[str, Any] | None,
|
|
technique_rollup: list[dict[str, Any]],
|
|
raw_tags: list[dict[str, Any]],
|
|
artifacts: list[dict[str, Any]],
|
|
smtp_targets: list[dict[str, Any]],
|
|
commands: list[str] | None = None,
|
|
) -> stix2.Bundle:
|
|
"""Assemble a STIX 2.1 Bundle for *attacker*.
|
|
|
|
All arguments are plain dicts (the shape returned by the DECNET
|
|
repo). Never raises — unknown/missing data is silently omitted from
|
|
the bundle.
|
|
"""
|
|
objs: list[Any] = []
|
|
|
|
org = _decnet_org()
|
|
objs.append(org)
|
|
|
|
# ── IP observation ──────────────────────────────────────────────
|
|
ipv4 = stix2.IPv4Address(value=attacker["ip"])
|
|
objs.append(ipv4)
|
|
|
|
fs = _aware(attacker.get("first_seen"))
|
|
ls = _aware(attacker.get("last_seen"))
|
|
now = datetime.now(timezone.utc)
|
|
ip_obs = stix2.ObservedData(
|
|
first_observed=fs or now,
|
|
last_observed=ls or now,
|
|
number_observed=max(1, attacker.get("event_count") or 1),
|
|
object_refs=[ipv4.id],
|
|
created_by_ref=org.id,
|
|
)
|
|
objs.append(ip_obs)
|
|
|
|
# ── Threat actor ─────────────────────────────────────────────────
|
|
ta = _threat_actor(attacker, identity, org.id)
|
|
objs.append(ta)
|
|
|
|
# ── ATT&CK — attack-patterns + uses relationships + sightings ───
|
|
# Build per-technique once; sightings reference the same AP STIX ID.
|
|
ap_stix_ids: dict[str, str] = {} # technique_id → attack-pattern STIX id
|
|
for row in technique_rollup:
|
|
tid = row.get("sub_technique_id") or row.get("technique_id")
|
|
if not tid or tid in ap_stix_ids:
|
|
continue
|
|
ap = _attack_pattern_sdo(tid, org.id)
|
|
if ap is None:
|
|
continue
|
|
ap_stix_ids[tid] = ap.id
|
|
objs.append(ap)
|
|
objs.append(
|
|
stix2.Relationship(
|
|
source_ref=ta.id,
|
|
target_ref=ap.id,
|
|
relationship_type="uses",
|
|
created_by_ref=org.id,
|
|
)
|
|
)
|
|
|
|
for tag in raw_tags:
|
|
tid = tag.get("sub_technique_id") or tag.get("technique_id")
|
|
if not tid or tid not in ap_stix_ids:
|
|
continue
|
|
ts = _aware(tag.get("created_at"))
|
|
if ts is None:
|
|
ts = now
|
|
objs.append(
|
|
stix2.Sighting(
|
|
sighting_of_ref=ap_stix_ids[tid],
|
|
first_seen=ts,
|
|
last_seen=ts,
|
|
count=1,
|
|
where_sighted_refs=[org.id],
|
|
observed_data_refs=[ip_obs.id],
|
|
created_by_ref=org.id,
|
|
)
|
|
)
|
|
|
|
# ── Artifacts (file_captured log rows) ──────────────────────────
|
|
for art in artifacts:
|
|
fields = art.get("fields") or {}
|
|
if isinstance(fields, str):
|
|
try:
|
|
fields = json.loads(fields)
|
|
except Exception:
|
|
fields = {}
|
|
sha = fields.get("sha256") or fields.get("hash")
|
|
if not sha:
|
|
continue
|
|
file_kwargs: dict[str, Any] = {"hashes": {"SHA-256": sha.lower()}}
|
|
name = fields.get("filename") or fields.get("stored_as")
|
|
if name:
|
|
file_kwargs["name"] = name
|
|
f = stix2.File(**file_kwargs)
|
|
objs.append(f)
|
|
fts = _aware(art.get("timestamp"))
|
|
objs.append(
|
|
stix2.ObservedData(
|
|
first_observed=fts or now,
|
|
last_observed=fts or now,
|
|
number_observed=1,
|
|
object_refs=[f.id],
|
|
created_by_ref=org.id,
|
|
)
|
|
)
|
|
|
|
# ── SMTP targets ────────────────────────────────────────────────
|
|
for tgt in smtp_targets:
|
|
domain = tgt.get("domain")
|
|
if not domain:
|
|
continue
|
|
dn = stix2.DomainName(value=domain)
|
|
objs.append(dn)
|
|
s_fs = _aware(tgt.get("first_seen"))
|
|
s_ls = _aware(tgt.get("last_seen"))
|
|
objs.append(
|
|
stix2.ObservedData(
|
|
first_observed=s_fs or now,
|
|
last_observed=s_ls or now,
|
|
number_observed=max(1, tgt.get("count") or 1),
|
|
object_refs=[dn.id],
|
|
created_by_ref=org.id,
|
|
)
|
|
)
|
|
|
|
# ── Shell commands (process SCOs + observed-data) ────────────────
|
|
seen_cmds: set[str] = set()
|
|
for cmd_line in commands or []:
|
|
if not cmd_line or cmd_line in seen_cmds:
|
|
continue
|
|
seen_cmds.add(cmd_line)
|
|
proc = stix2.Process(command_line=cmd_line, is_hidden=False)
|
|
objs.append(proc)
|
|
objs.append(
|
|
stix2.ObservedData(
|
|
first_observed=fs or now,
|
|
last_observed=ls or now,
|
|
number_observed=1,
|
|
object_refs=[proc.id],
|
|
created_by_ref=org.id,
|
|
)
|
|
)
|
|
|
|
# ── Intel note ───────────────────────────────────────────────────
|
|
if intel:
|
|
note = _intel_note(intel, ta.id, org.id)
|
|
objs.append(note)
|
|
|
|
return stix2.Bundle(objects=objs, allow_custom=True)
|
|
|
|
|
|
def build_fleet_bundle(
|
|
rows: list[dict[str, Any]],
|
|
ttp_by_attacker: dict[str, list[dict[str, Any]]],
|
|
) -> stix2.Bundle:
|
|
"""Assemble a STIX 2.1 Bundle covering all attackers in *rows*.
|
|
|
|
Deduplicates by STIX ID — attack-pattern SDOs with the same canonical
|
|
MITRE UUID appear once regardless of how many attackers used the technique.
|
|
Per-tag Sightings, Artifacts, and SMTP targets are omitted in fleet mode
|
|
(too verbose; use the per-attacker endpoint for full fidelity).
|
|
"""
|
|
objs_by_id: dict[str, Any] = {}
|
|
|
|
for row in rows:
|
|
raw_cmds = row.get("commands") or []
|
|
if isinstance(raw_cmds, str):
|
|
try:
|
|
raw_cmds = json.loads(raw_cmds)
|
|
except Exception:
|
|
raw_cmds = []
|
|
cmds = [
|
|
str(e.get("command_text") or e.get("command") or "").strip()
|
|
for e in raw_cmds
|
|
if isinstance(e, dict) and (e.get("command_text") or e.get("command"))
|
|
]
|
|
|
|
intel = row.get("threat_intel")
|
|
bundle = build_attacker_bundle(
|
|
attacker=row,
|
|
behavior=None,
|
|
identity=None,
|
|
intel=intel,
|
|
technique_rollup=ttp_by_attacker.get(row["uuid"], []),
|
|
raw_tags=[],
|
|
artifacts=[],
|
|
smtp_targets=[],
|
|
commands=cmds,
|
|
)
|
|
for obj in bundle.objects:
|
|
objs_by_id[obj.id] = obj
|
|
|
|
return stix2.Bundle(objects=list(objs_by_id.values()), allow_custom=True)
|