Implementing Taxii Server With Opentaxii

Implementing TAXII Server with OpenTAXII

Overview

TAXII (Trusted Automated eXchange of Intelligence Information) is an OASIS standard protocol for exchanging cyber threat intelligence over HTTPS. OpenTAXII is an open-source TAXII server implementation by EclecticIQ that supports TAXII 1.x, while the OASIS cti-taxii-server provides a TAXII 2.1 reference implementation. This skill covers deploying a TAXII server, configuring collections for threat intelligence feeds, publishing STIX 2.1 bundles, and integrating with SIEM/SOAR platforms for automated indicator ingestion.

When to Use

• When deploying or configuring implementing taxii server with opentaxii capabilities in your environment
• When establishing security controls aligned to compliance requirements
• When building or improving security architecture for this domain
• When conducting security assessments that require this implementation

Common Misconfigurations & Verification

• Discovery/API-root URL mismatch: the discovery.default and api_roots URLs in the config must match the externally reachable HTTPS base, or clients discover endpoints they cannot reach. Verify with a real Server(...).api_roots call from outside the host.
• Collection IDs not stable: reusing or regenerating a collection id orphans published objects and breaks consumer poll state. Pin UUIDs in config and never recycle them.
• Permission flags wrong: a collection with can_write: false silently rejects publishes; can_read: false returns empty polls. Confirm read/write per collection against the intended sharing model (hub-and-spoke vs peer-to-peer).
• Media-type negotiation: medallion/OpenTAXII require application/taxii+json;version=2.1 and application/stix+json;version=2.1; wrong headers yield 406/415.
• Default credentials and volatile backend: the sample *_change_me passwords and MemoryBackend are not production-safe - data is lost on restart and auth is weak. Switch to a persistent backend and real TLS certs.
• Verification: hit /taxii2/ for discovery, list collections with the correct read/write flags, publish a bundle and confirm the Status response success_count, then poll it back and validate the IOCs forward into the SIEM.

Prerequisites

• Python 3.9+ with medallion, stix2, taxii2-client, opentaxii, cabby libraries
• Docker and Docker Compose for containerized deployment
• Understanding of STIX 2.1 objects (Indicator, Malware, Attack Pattern, Relationship)
• Familiarity with REST APIs and HTTPS configuration
• TLS certificates for production deployment

Key Concepts

TAXII 2.1 Architecture

TAXII 2.1 defines three services: Discovery (find available API roots), API Root (entry point for collections), and Collections (repositories of CTI objects). Collections support two access models: the Collection endpoint allows consumers to poll for objects, and the Status endpoint tracks the result of add operations. TAXII uses HTTP content negotiation with application/taxii+json;version=2.1.

Sharing Models

TAXII supports hub-and-spoke (central server distributes to consumers), peer-to-peer (bidirectional sharing between partners), and source-subscriber (producer publishes, consumers subscribe) models. Each collection can have read-only, write-only, or read-write access controls.

STIX 2.1 Content

TAXII transports STIX 2.1 bundles containing Structured Threat Information objects: Indicators (detection patterns), Observed Data, Malware, Attack Patterns, Threat Actors, Intrusion Sets, Campaigns, Relationships, and Sightings. Each object has a unique STIX ID, creation/modification timestamps, and optional TLP marking definitions.

Workflow

Step 1: Deploy TAXII 2.1 Server with Medallion

# Install medallion (OASIS reference implementation)
# pip install medallion

# medallion_config.json
import json

config = {
    "backend": {
        "module_class": "MemoryBackend",
        "filename": "taxii_data.json"
    },
    "users": {
        "admin": "admin_password_change_me",
        "analyst": "analyst_password_change_me",
        "readonly": "readonly_password_change_me"
    },
    "taxii": {
        "max_content_length": 10485760
    }
}

# Create initial data store
taxii_data = {
    "discovery": {
        "title": "Threat Intelligence TAXII Server",
        "description": "TAXII 2.1 server for sharing CTI indicators",
        "contact": "soc@organization.com",
        "default": "https://taxii.organization.com/api/",
        "api_roots": ["https://taxii.organization.com/api/"]
    },
    "api_roots": {
        "api": {
            "title": "Threat Intelligence API Root",
            "description": "Primary API root for threat intelligence sharing",
            "versions": ["application/taxii+json;version=2.1"],
            "max_content_length": 10485760,
            "collections": {
                "malware-iocs": {
                    "id": "91a7b528-80eb-42ed-a74d-c6fbd5a26116",
                    "title": "Malware IOCs",
                    "description": "Indicators of compromise from malware analysis",
                    "can_read": True,
                    "can_write": True,
                    "media_types": ["application/stix+json;version=2.1"]
                },
                "apt-intelligence": {
                    "id": "52892447-4d7e-4f70-b94a-5460e242dd23",
                    "title": "APT Intelligence",
                    "description": "Advanced persistent threat group intelligence",
                    "can_read": True,
                    "can_write": True,
                    "media_types": ["application/stix+json;version=2.1"]
                },
                "phishing-indicators": {
                    "id": "64993447-4d7e-4f70-b94a-5460e242ee34",
                    "title": "Phishing Indicators",
                    "description": "Phishing URLs, domains, and email indicators",
                    "can_read": True,
                    "can_write": True,
                    "media_types": ["application/stix+json;version=2.1"]
                }
            }
        }
    }
}

with open("medallion_config.json", "w") as f:
    json.dump(config, f, indent=2)
with open("taxii_data.json", "w") as f:
    json.dump(taxii_data, f, indent=2)
print("[+] TAXII server configuration created")

Step 2: Docker Deployment

# docker-compose.yml
version: '3.8'
services:
  taxii-server:
    image: python:3.11-slim
    container_name: taxii-server
    working_dir: /app
    volumes:
      - ./medallion_config.json:/app/medallion_config.json
      - ./taxii_data.json:/app/taxii_data.json
      - ./certs:/app/certs
    ports:
      - "6100:6100"
    command: >
      bash -c "pip install medallion &&
      medallion --host 0.0.0.0 --port 6100
      --config /app/medallion_config.json"
    restart: unless-stopped
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:6100/taxii2/"]
      interval: 30s
      timeout: 10s
      retries: 3

Step 3: Publish STIX 2.1 Objects to Collections

from stix2 import Indicator, Malware, Relationship, Bundle, TLP_WHITE
from taxii2client.v21 import Server, Collection, as_pages
import json
from datetime import datetime

class TAXIIPublisher:
    def __init__(self, server_url, username, password):
        self.server = Server(
            server_url,
            user=username,
            password=password,
        )

    def list_collections(self):
        """List all available collections."""
        api_root = self.server.api_roots[0]
        for collection in api_root.collections:
            print(f"  [{collection.id}] {collection.title} "
                  f"(read={collection.can_read}, write={collection.can_write})")
        return api_root.collections

    def publish_indicators(self, collection_id, indicators):
        """Publish STIX indicators to a TAXII collection."""
        api_root = self.server.api_roots[0]
        collection = Collection(
            f"{api_root.url}collections/{collection_id}/",
            user=self.server._user,
            password=self.server._password,
        )
        bundle = Bundle(objects=indicators)
        response = collection.add_objects(bundle.serialize())
        print(f"[+] Published {len(indicators)} objects to {collection_id}")
        print(f"    Status: {response.status}")
        return response

    def create_malware_indicators(self):
        """Create sample STIX malware indicators."""
        malware = Malware(
            name="SUNBURST",
            description="Backdoor used in SolarWinds supply chain attack (2020). "
                        "Trojanized SolarWinds.Orion.Core.BusinessLayer.dll module.",
            malware_types=["backdoor", "trojan"],
            is_family=True,
            object_marking_refs=[TLP_WHITE],
        )

        indicator_hash = Indicator(
            name="SUNBURST SHA-256 Hash",
            description="SHA-256 hash of trojanized SolarWinds Orion DLL",
            pattern="[file:hashes.'SHA-256' = "
                    "'32519b85c0b422e4656de6e6c41878e95fd95026267daab4215ee59c107d6c77']",
            pattern_type="stix",
            valid_from=datetime(2020, 12, 13),
            indicator_types=["malicious-activity"],
            object_marking_refs=[TLP_WHITE],
        )

        indicator_domain = Indicator(
            name="SUNBURST C2 Domain Pattern",
            description="DGA domain pattern used by SUNBURST for C2",
            pattern="[domain-name:value MATCHES "
                    "'^[a-z0-9]{4,}\\.appsync-api\\..*\\.avsvmcloud\\.com$']",
            pattern_type="stix",
            valid_from=datetime(2020, 12, 13),
            indicator_types=["malicious-activity"],
            object_marking_refs=[TLP_WHITE],
        )

        rel = Relationship(
            relationship_type="indicates",
            source_ref=indicator_hash.id,
            target_ref=malware.id,
        )

        return [malware, indicator_hash, indicator_domain, rel]

publisher = TAXIIPublisher(
    "https://taxii.organization.com/taxii2/",
    "admin", "admin_password_change_me"
)
collections = publisher.list_collections()
indicators = publisher.create_malware_indicators()
publisher.publish_indicators("91a7b528-80eb-42ed-a74d-c6fbd5a26116", indicators)

Step 4: Consume Intelligence from TAXII Collections

from taxii2client.v21 import Server, Collection, as_pages
import json

class TAXIIConsumer:
    def __init__(self, server_url, username, password):
        self.server = Server(server_url, user=username, password=password)

    def poll_collection(self, collection_id, added_after=None):
        """Poll a collection for new STIX objects."""
        api_root = self.server.api_roots[0]
        collection = Collection(
            f"{api_root.url}collections/{collection_id}/",
            user=self.server._user,
            password=self.server._password,
        )

        kwargs = {}
        if added_after:
            kwargs["added_after"] = added_after

        all_objects = []
        for bundle in as_pages(collection.get_objects, per_request=50, **kwargs):
            objects = json.loads(bundle).get("objects", [])
            all_objects.extend(objects)

        indicators = [o for o in all_objects if o.get("type") == "indicator"]
        malware = [o for o in all_objects if o.get("type") == "malware"]
        relationships = [o for o in all_objects if o.get("type") == "relationship"]

        print(f"[+] Polled {len(all_objects)} objects: "
              f"{len(indicators)} indicators, {len(malware)} malware, "
              f"{len(relationships)} relationships")
        return all_objects

    def extract_iocs_for_siem(self, stix_objects):
        """Extract IOCs from STIX objects for SIEM ingestion."""
        iocs = []
        for obj in stix_objects:
            if obj.get("type") == "indicator":
                pattern = obj.get("pattern", "")
                iocs.append({
                    "id": obj.get("id"),
                    "name": obj.get("name", ""),
                    "pattern": pattern,
                    "valid_from": obj.get("valid_from", ""),
                    "indicator_types": obj.get("indicator_types", []),
                    "confidence": obj.get("confidence", 0),
                })
        return iocs

consumer = TAXIIConsumer(
    "https://taxii.organization.com/taxii2/",
    "analyst", "analyst_password_change_me"
)
objects = consumer.poll_collection("91a7b528-80eb-42ed-a74d-c6fbd5a26116")
iocs = consumer.extract_iocs_for_siem(objects)

Step 5: Integrate with SIEM/SOAR

import requests

def push_to_splunk(iocs, splunk_url, hec_token):
    """Push extracted IOCs to Splunk via HEC."""
    headers = {"Authorization": f"Splunk {hec_token}"}
    for ioc in iocs:
        event = {
            "event": ioc,
            "sourcetype": "stix:indicator",
            "source": "taxii-server",
            "index": "threat_intel",
        }
        resp = requests.post(
            f"{splunk_url}/services/collector/event",
            headers=headers,
            json=event,
            verify=not os.environ.get("SKIP_TLS_VERIFY", "").lower() == "true",  # Set SKIP_TLS_VERIFY=true for self-signed certs in lab environments
        )
        if resp.status_code != 200:
            print(f"[-] Splunk HEC error: {resp.text}")
    print(f"[+] Pushed {len(iocs)} IOCs to Splunk")

def push_to_elasticsearch(iocs, es_url, index="threat-intel"):
    """Push IOCs to Elasticsearch."""
    for ioc in iocs:
        resp = requests.post(
            f"{es_url}/{index}/_doc",
            json=ioc,
            headers={"Content-Type": "application/json"},
        )
        if resp.status_code not in (200, 201):
            print(f"[-] ES error: {resp.text}")
    print(f"[+] Indexed {len(iocs)} IOCs in Elasticsearch")

Validation Criteria

• TAXII 2.1 server deployed and accessible via HTTPS
• Collections created with appropriate read/write permissions
• STIX 2.1 bundles published successfully to collections
• Consumer can poll and retrieve objects with filtering
• IOCs extracted and forwarded to SIEM platform
• Authentication and authorization enforced correctly

References

• TAXII 2.1 Specification
• OASIS CTI Documentation
• EclecticIQ OpenTAXII
• cti-taxii-server (Medallion)
• taxii2-client Python Library
• Kraven Security: STIX/TAXII Complete Guide