使用 OpenCTI 构建 IOC 丰富化管道 是做什么的？
概述
OpenCTI 是一个用于管理网络威胁情报知识的开源平台，采用 STIX 2.1 作为其原生数据模型。本技能介绍如何利用 OpenCTI 的连接器生态系统构建自动化 IOC 丰富化管道，集成 VirusTotal、Shodan、AbuseIPDB、GreyNoise 等情报源，为新摄入的威胁指标添加上下文，并将其与已知威胁行为体和攻击活动关联，同时进行优先级评分以供分析师处理。
适用场景
- 在您的环境中部署或配置构建 IOC 丰富化管道能力时
- 建立符合合规要求的安全控制措施时
- 构建或改进此领域的安全架构时
- 实施需要此实现的安全评估时
前提条件
- Docker 和 Docker Compose（用于部署 OpenCTI）
- Python 3.9+ 及
pycti库 - 丰富化服务的 API 密钥：VirusTotal、Shodan、AbuseIPDB、GreyNoise
- 理解 STIX 2.1 数据模型及其关系
- ElasticSearch 或 OpenSearch（用于 OpenCTI 后端）
- RabbitMQ 或 Redis（用于连接器消息传递）
关键概念
OpenCTI 架构
OpenCTI 使用 GraphQL API 作为前端，后端由 ElasticSearch 提供存储支持，Redis/RabbitMQ 负责连接器通信。数据以 STIX 2.1 对象及其关系的原生形式存储。连接器分为以下几类：外部导入（订阅源摄取）、内部导入（文件解析）、内部丰富化（添加上下文）和流式导出（实时导出）。
丰富化连接器模型
内部丰富化连接器在新可观测对象创建时自动触发，也可由分析师手动激活。每个连接器接收 STIX 对象，查询外部服务，并返回一个 STIX 2.1 Bundle，其中包含对原始可观测对象的上下文补充、标签和关系。
置信度评分
OpenCTI 使用 0-100 的置信度评分体系。丰富化连接器可根据外部验证结果（如 VirusTotal 检测率、Shodan 暴露数据、AbuseIPDB 报告数量、GreyNoise 分类结果）更新指标的置信度分数。
工作流
步骤 1：使用 Docker Compose 部署 OpenCTI
# docker-compose.yml（关键服务）
version: '3'
services:
opencti:
image: opencti/platform:6.4.4
environment:
- APP__PORT=8080
- [email protected]
- APP__ADMIN__PASSWORD=ChangeMeNow
- APP__ADMIN__TOKEN=your-admin-token-uuid
- ELASTICSEARCH__URL=http://elasticsearch:9200
- MINIO__ENDPOINT=minio
- RABBITMQ__HOSTNAME=rabbitmq
ports:
- "8080:8080"
depends_on:
- elasticsearch
- minio
- rabbitmq
- redis
connector-virustotal:
image: opencti/connector-virustotal:6.4.4
environment:
- OPENCTI_URL=http://opencti:8080
- OPENCTI_TOKEN=your-admin-token-uuid
- CONNECTOR_ID=connector-virustotal-id
- CONNECTOR_NAME=VirusTotal
- CONNECTOR_SCOPE=StixFile,Artifact,IPv4-Addr,Domain-Name,Url
- CONNECTOR_AUTO=true
- VIRUSTOTAL_TOKEN=your-vt-api-key
- VIRUSTOTAL_MAX_TLP=TLP:AMBER
connector-shodan:
image: opencti/connector-shodan:6.4.4
environment:
- OPENCTI_URL=http://opencti:8080
- OPENCTI_TOKEN=your-admin-token-uuid
- CONNECTOR_ID=connector-shodan-id
- CONNECTOR_NAME=Shodan
- CONNECTOR_SCOPE=IPv4-Addr
- CONNECTOR_AUTO=true
- SHODAN_TOKEN=your-shodan-api-key
- SHODAN_MAX_TLP=TLP:AMBER
connector-abuseipdb:
image: opencti/connector-abuseipdb:6.4.4
environment:
- OPENCTI_URL=http://opencti:8080
- OPENCTI_TOKEN=your-admin-token-uuid
- CONNECTOR_ID=connector-abuseipdb-id
- CONNECTOR_NAME=AbuseIPDB
- CONNECTOR_SCOPE=IPv4-Addr
- CONNECTOR_AUTO=true
- ABUSEIPDB_API_KEY=your-abuseipdb-key
步骤 2：构建自定义丰富化连接器
import os
from pycti import OpenCTIConnectorHelper, get_config_variable
from stix2 import (
Bundle, Indicator, Note, Relationship,
IPv4Address, DomainName
)
import requests
class CustomEnrichmentConnector:
def __init__(self):
config = {
"opencti": {
"url": os.environ.get("OPENCTI_URL"),
"token": os.environ.get("OPENCTI_TOKEN"),
},
"connector": {
"id": os.environ.get("CONNECTOR_ID"),
"name": "CustomEnrichment",
"scope": "IPv4-Addr,Domain-Name,Url",
"auto": True,
"type": "INTERNAL_ENRICHMENT",
},
}
self.helper = OpenCTIConnectorHelper(config)
self.helper.listen(self._process_message)
def _process_message(self, data):
entity_id = data["entity_id"]
stix_object = self.helper.api.stix_cyber_observable.read(id=entity_id)
if not stix_object:
return "Observable not found"
observable_type = stix_object["entity_type"]
observable_value = stix_object.get("value", "")
enrichment_results = []
if observable_type == "IPv4-Addr":
enrichment_results = self._enrich_ip(observable_value, entity_id)
elif observable_type == "Domain-Name":
enrichment_results = self._enrich_domain(observable_value, entity_id)
if enrichment_results:
bundle = Bundle(objects=enrichment_results, allow_custom=True)
self.helper.send_stix2_bundle(bundle.serialize())
return "Enrichment completed"
def _enrich_ip(self, ip_address, entity_id):
"""使用 GreyNoise、AbuseIPDB 上下文丰富 IP 地址。"""
objects = []
# GreyNoise Community API
try:
gn_response = requests.get(
f"https://api.greynoise.io/v3/community/{ip_address}",
headers={"key": os.environ.get("GREYNOISE_API_KEY")},
timeout=30,
)
if gn_response.status_code == 200:
gn_data = gn_response.json()
classification = gn_data.get("classification", "unknown")
noise = gn_data.get("noise", False)
riot = gn_data.get("riot", False)
note_content = (
f"## GreyNoise Enrichment\n"
f"- Classification: {classification}\n"
f"- Internet Noise: {noise}\n"
f"- RIOT (Benign Service): {riot}\n"
f"- Name: {gn_data.get('name', 'N/A')}\n"
f"- Last Seen: {gn_data.get('last_seen', 'N/A')}"
)
note = Note(
content=note_content,
object_refs=[entity_id],
abstract=f"GreyNoise: {classification}",
allow_custom=True,
)
objects.append(note)
# 根据分类添加标签
if classification == "malicious":
self.helper.api.stix_cyber_observable.add_label(
id=entity_id, label_name="greynoise:malicious"
)
elif riot:
self.helper.api.stix_cyber_observable.add_label(
id=entity_id, label_name="greynoise:benign-service"
)
except Exception as e:
self.helper.log_error(f"GreyNoise enrichment failed: {e}")
return objects
def _enrich_domain(self, domain, entity_id):
"""使用 WHOIS 和 DNS 上下文丰富域名。"""
objects = []
try:
# 使用 SecurityTrails API 进行域名丰富
st_response = requests.get(
f"https://api.securitytrails.com/v1/domain/{domain}",
headers={"APIKEY": os.environ.get("SECURITYTRAILS_API_KEY")},
timeout=30,
)
if st_response.status_code == 200:
st_data = st_response.json()
current_dns = st_data.get("current_dns", {})
a_records = [
r.get("ip") for r in current_dns.get("a", {}).get("values", [])
]
note_content = (
f"## SecurityTrails Enrichment\n"
f"- A Records: {', '.join(a_records)}\n"
f"- Alexa Rank: {st_data.get('alexa_rank', 'N/A')}\n"
f"- Hostname: {st_data.get('hostname', 'N/A')}"
)
note = Note(
content=note_content,
object_refs=[entity_id],
abstract=f"SecurityTrails: {domain}",
allow_custom=True,
)
objects.append(note)
except Exception as e:
self.helper.log_error(f"SecurityTrails enrichment failed: {e}")
return objects
if __name__ == "__main__":
connector = CustomEnrichmentConnector()