tracking-threat-actor-infrastructure

# 追踪威胁行为者基础设施

## 概述

威胁行为者基础设施追踪涉及监控和映射对手控制的资产，包括命令与控制（C2）服务器、钓鱼（Phishing）域名、漏洞利用工具包宿主、防弹托管（Bulletproof Hosting）和暂存服务器。本技能涵盖使用被动 DNS（Passive DNS）、证书透明度（Certificate Transparency）日志、Shodan/Censys 扫描、WHOIS 分析和网络指纹技术，随时间推移发现、追踪和跨威胁行为者基础设施进行关联分析。

## 前置条件

- Python 3.9+，安装 `shodan`、`censys`、`requests`、`stix2` 库
- API 密钥：Shodan、Censys、VirusTotal、SecurityTrails、PassiveTotal
- 理解 DNS、TLS/SSL 证书、IP 分配、ASN 结构
- 熟悉被动 DNS 和证书透明度概念
- 可访问域名注册（WHOIS）查询服务

## 核心概念

### 基础设施关联分析（Infrastructure Pivoting）
关联分析是利用一个已知指标发现相关基础设施的技术。从已知的 C2 IP 地址出发，分析师可通过以下方式进行关联：被动 DNS（发现域名）、反向 WHOIS（发现相关注册信息）、SSL 证书（发现共享证书）、SSH 密钥指纹、HTTP 响应指纹、JARM/JA3S 哈希，以及 WHOIS 注册人数据。

### 被动 DNS
被动 DNS 数据库记录在递归解析器处观测到的 DNS 查询/响应数据。这允许分析师查找历史域名到 IP 的映射、发现托管在已知 C2 IP 上的域名，以及识别快速流量（Fast-Flux）或域名生成算法（DGA）行为。

### 证书透明度
证书透明度（CT）日志公开记录 CA 机构签发的所有 SSL/TLS 证书。监控 CT 日志可以发现为可疑域名注册的新证书，有助于在 C2 基础设施激活前识别钓鱼站点。

### 网络指纹
- **JARM**：主动 TLS 服务器指纹（TLS 握手响应的哈希）
- **JA3S**：被动 TLS 服务器指纹（Server Hello 的哈希）
- **HTTP 头部**：服务器标识、自定义头部、响应模式
- **Favicon 哈希**：用于服务器识别的 HTTP favicon 哈希

## 实操步骤

### 步骤 1：Shodan 基础设施发现

```python
import shodan

api = shodan.Shodan("YOUR_SHODAN_API_KEY")

def discover_infrastructure(ip_address):
    """发现目标 IP 的服务和元数据。"""
    try:
        host = api.host(ip_address)
        return {
            "ip": host["ip_str"],
            "org": host.get("org", ""),
            "asn": host.get("asn", ""),
            "isp": host.get("isp", ""),
            "country": host.get("country_name", ""),
            "city": host.get("city", ""),
            "os": host.get("os"),
            "ports": host.get("ports", []),
            "vulns": host.get("vulns", []),
            "hostnames": host.get("hostnames", []),
            "domains": host.get("domains", []),
            "tags": host.get("tags", []),
            "services": [
                {
                    "port": svc.get("port"),
                    "transport": svc.get("transport"),
                    "product": svc.get("product", ""),
                    "version": svc.get("version", ""),
                    "ssl_cert": svc.get("ssl", {}).get("cert", {}).get("subject", {}),
                    "jarm": svc.get("ssl", {}).get("jarm", ""),
                }
                for svc in host.get("data", [])
            ],
        }
    except shodan.APIError as e:
        print(f"[-] Shodan 错误: {e}")
        return None

def search_c2_framework(framework_name):
    """搜索 Shodan 中已知 C2 框架的特征。"""
    c2_queries = {
        "cobalt-strike": 'product:"Cobalt Strike Beacon"',
        "metasploit": 'product:"Metasploit"',
        "covenant": 'http.html:"Covenant" http.title:"Covenant"',
        "sliver": 'ssl.cert.subject.cn:"multiplayer" ssl.cert.issuer.cn:"operators"',
        "havoc": 'http.html_hash:-1472705893',
    }

    query = c2_queries.get(framework_name.lower(), framework_name)
    results = api.search(query, limit=100)

    hosts = []
    for match in results.get("matches", []):
        hosts.append({
            "ip": match["ip_str"],
            "port": match["port"],
            "org": match.get("org", ""),
            "country": match.get("location", {}).get("country_name", ""),
            "asn": match.get("asn", ""),
            "timestamp": match.get("timestamp", ""),
        })

    return hosts
```

### 步骤 2：被动 DNS 关联分析

```python
import requests

def passive_dns_lookup(indicator, api_key, indicator_type="ip"):
    """通过 SecurityTrails 查询被动 DNS 记录。"""
    base_url = "https://api.securitytrails.com/v1"
    headers = {"APIKEY": api_key, "Accept": "application/json"}

    if indicator_type == "ip":
        url = f"{base_url}/search/list"
        payload = {
            "filter": {"ipv4": indicator}
        }
        resp = requests.post(url, json=payload, headers=headers, timeout=30)
    else:
        url = f"{base_url}/domain/{indicator}/subdomains"
        resp = requests.get(url, headers=headers, timeout=30)

    if resp.status_code == 200:
        return resp.json()
    return None


def query_passive_total(indicator, user, api_key):
    """通过 PassiveTotal 查询被动 DNS 和 WHOIS 数据。"""
    base_url = "https://api.passivetotal.org/v2"
    auth = (user, api_key)

    # 被动 DNS 查询
    pdns_resp = requests.get(
        f"{base_url}/dns/passive",
        params={"query": indicator},
        auth=auth,
        timeout=30,
    )

    # WHOIS 查询
    whois_resp = requests.get(
        f"{base_url}/whois",
        params={"query": indicator},
        auth=auth,
        timeout=30,
    )

    results = {}
    if pdns_resp.status_code == 200:
        results["passive_dns"] = pdns_resp.json().get("results", [])
    if whois_resp.status_code == 200:
        results["whois"] = whois_resp.json()

    return results
```

### 步骤 3：证书透明度监控

```python
import requests

def search_ct_logs(domain):
    """通过 crt.sh 搜索证书透明度日志。"""
    resp = requests.get(
        f"https://crt.sh/?q=%.{domain}&output=json",
        timeout=30,
    )

    if resp.status_code == 200:
        certs = resp.json()
        unique_domains = set()
        cert_info = []

        for cert in certs:
            name_value = cert.get("name_value", "")
            for name in name_value.split("\n"):
                unique_domains.add(name.strip())

            cert_info.append({
                "id": cert.get("id"),
                "issuer": cert.get("issuer_name", ""),
                "common_name": cert.get("common_name", ""),
                "name_value": name_value,
                "not_before": cert.get("not_before", ""),
                "not_after": cert.get("not_after", ""),
                "serial_number": cert.get("serial_number", ""),
            })

        return {
            "domain": domain,
            "total_certificates": len(certs),
            "unique_domains": sorted(unique_domains),
            "certificates": cert_info[:50],
        }
    return None


def monitor_new_certs(domains, interval_hours=1):
    """监控一组域名新签发的证书。"""
    from datetime import datetime, timedelta

    cutoff = (datetime.utcnow() - timedelta(hours=interval_hours)).isoformat()
    new_certs = []

    for domain in domains:
        result = search_ct_logs(domain)
        if result:
            for cert in result.get("certificates", []):
                if cert.get("not_before", "") > cutoff:
                    new_certs.append({
                        "domain": domain,
                        "cert": cert,
                    })

    return new_certs
```

### 步骤 4：基础设施关联与时间线

```python
from datetime import datetime

def build_infrastructure_timeline(indicators):
    """构建基础设施变化时间线。"""
    timeline = []

    for ind in indicators:
        if "passive_dns" in ind:
            for record in ind["passive_dns"]:
                timeline.append({
                    "timestamp": record.get("firstSeen", ""),
                    "event": "dns_resolution",
                    "source": record.get("resolve", ""),
                    "target": record.get("value", ""),
                    "record_type": record.get("recordType", ""),
                })

        if "certificates" in ind:
            for cert in ind["certificates"]:
                timeline.append({
                    "timestamp": cert.get("not_before", ""),
                    "event": "certificate_issued",
                    "domain": cert.get("common_name", ""),
                    "issuer": cert.get("issuer", ""),
                })

    timeline.sort(key=lambda x: x.get("timestamp", ""))
    return timeline
```

## 验证标准

- Shodan/Censys 查询返回目标 IP 的基础设施详情
- 被动 DNS 揭示历史域名-IP 映射关系
- 证书透明度搜索找到关联域名
- 基础设施关联分析发现新的相关指标
- 时间线显示基础设施随时间的演变
- 结果可导出为 STIX 2.1 基础设施对象

## 参考资料

- [Shodan API Documentation](https://developer.shodan.io/api)
- [Censys Search API](https://search.censys.io/api)
- [SecurityTrails API](https://securitytrails.com/corp/api)
- [crt.sh Certificate Transparency](https://crt.sh/)
- [PassiveTotal API](https://api.passivetotal.org/api/docs/)
- [JARM Fingerprinting](https://github.com/salesforce/jarm)