building-vulnerability-scanning-workflow

构建漏洞扫描工作流

何时使用

在以下情况下使用本技能：

• SOC 团队需要建立或改进周期性漏洞扫描计划
• 扫描结果需要借助资产上下文和威胁情报，在原始 CVSS 评分之外进行优先级排序
• 漏洞数据必须集成到 SIEM 中，以便与利用尝试进行关联
• 修复跟踪需要借助基于 SLA 的仪表盘和报告实现规范化

请勿使用于渗透测试或主动利用——漏洞扫描用于识别弱点，渗透测试用于验证可利用性。

前置条件

• 漏洞扫描器（Tenable Nessus Professional、Qualys VMDR 或 OpenVAS/Greenbone）
• 带有关键性分类的资产清单（业务关键、标准、开发）
• 从扫描器到所有目标网段的网络访问（基于 Agent 或网络扫描）
• 用于扫描结果摄取和关联的 SIEM 集成
• 用于修复跟踪的补丁管理系统（WSUS、SCCM、Intune）

工作流

步骤 1：定义扫描范围和计划

创建覆盖所有资产类型的扫描策略：

Nessus 扫描配置（API）：

import requests

nessus_url = "https://nessus.company.com:8834"
headers = {"X-ApiKeys": f"accessKey={access_key};secretKey={secret_key}"}

# Create scan policy
policy = {
    "uuid": "advanced",
    "settings": {
        "name": "SOC Weekly Infrastructure Scan",
        "description": "Weekly credentialed scan of all server and workstation segments",
        "scanner_id": 1,
        "policy_id": 0,
        "text_targets": "10.0.0.0/16, 172.16.0.0/12",
        "launch": "WEEKLY",
        "starttime": "20240315T020000",
        "rrules": "FREQ=WEEKLY;INTERVAL=1;BYDAY=SA",
        "enabled": True
    },
    "credentials": {
        "add": {
            "Host": {
                "Windows": [{
                    "domain": "company.local",
                    "username": "nessus_svc",
                    "password": "SCAN_SERVICE_PASSWORD",
                    "auth_method": "Password"
                }],
                "SSH": [{
                    "username": "nessus_svc",
                    "private_key": "/path/to/nessus_key",
                    "auth_method": "public key"
                }]
            }
        }
    }
}

response = requests.post(f"{nessus_url}/scans", headers=headers, json=policy,
                         verify=not os.environ.get("SKIP_TLS_VERIFY", "").lower() == "true")  # Set SKIP_TLS_VERIFY=true for self-signed certs in lab environments
scan_id = response.json()["scan"]["id"]
print(f"Scan created: ID {scan_id}")

通过 API 进行 Qualys VMDR 扫描：

import qualysapi

conn = qualysapi.connect(
    hostname="qualysapi.qualys.com",
    username="api_user",
    password="API_PASSWORD"
)

# Launch vulnerability scan
params = {
    "action": "launch",
    "scan_title": "Weekly_Infrastructure_Scan",
    "ip": "10.0.0.0/16",
    "option_id": "123456",  # Scan profile ID
    "iscanner_name": "Internal_Scanner_01",
    "priority": "0"
}

response = conn.request("/api/2.0/fo/scan/", params)
print(f"Scan launched: {response}")

步骤 2：处理扫描结果并确定优先级

下载结果并应用基于风险的优先级排序：

import requests
import csv

# Export Nessus results
response = requests.get(
    f"{nessus_url}/scans/{scan_id}/export",
    headers=headers,
    params={"format": "csv"},
    verify=not os.environ.get("SKIP_TLS_VERIFY", "").lower() == "true",  # Set SKIP_TLS_VERIFY=true for self-signed certs in lab environments
)

# Parse and prioritize
vulns = []
reader = csv.DictReader(response.text.splitlines())
for row in reader:
    cvss = float(row.get("CVSS v3.0 Base Score", 0))
    asset_criticality = get_asset_criticality(row["Host"])  # From asset inventory

    # Risk-based priority calculation
    risk_score = cvss * asset_criticality_multiplier(asset_criticality)

    # Boost score if actively exploited (check CISA KEV)
    if row.get("CVE") in cisa_kev_list:
        risk_score *= 1.5

    vulns.append({
        "host": row["Host"],
        "plugin_name": row["Name"],
        "severity": row["Risk"],
        "cvss": cvss,
        "cve": row.get("CVE", "N/A"),
        "risk_score": round(risk_score, 1),
        "asset_criticality": asset_criticality,
        "kev": row.get("CVE") in cisa_kev_list
    })

# Sort by risk score
vulns.sort(key=lambda x: x["risk_score"], reverse=True)

CISA KEV（已知被利用漏洞）检查：

import requests

kev_response = requests.get(
    "https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json"
)
kev_data = kev_response.json()
cisa_kev_list = {v["cveID"] for v in kev_data["vulnerabilities"]}

# Check if vulnerability is actively exploited
def is_actively_exploited(cve_id):
    return cve_id in cisa_kev_list

步骤 3：定义修复 SLA

应用基于 SLA 的修复时间线：

优先级	CVSS 范围	资产类型	SLA	示例
P1 严重	9.0-10.0 + KEV	所有资产	24 小时	生产服务器上的 Log4Shell、EternalBlue
P2 高	7.0-8.9 或 9.0+ 非 KEV	业务关键	7 天	无已知利用的 RCE
P3 中	4.0-6.9	业务关键	30 天	需认证的权限提升
P4 低	0.1-3.9	标准	90 天	信息泄露、低影响 DoS
P5 信息性	0.0	开发	下一周期	最佳实践发现、配置加固

步骤 4：与 SIEM 集成以检测利用行为

将漏洞扫描数据与 SIEM 告警关联，以检测主动利用行为：

index=vulnerability sourcetype="nessus:scan"
| eval vuln_key = Host.":".CVE
| join vuln_key type=left [
    search index=ids_ips sourcetype="snort" OR sourcetype="suricata"
    | eval vuln_key = dest_ip.":".cve_id
    | stats count AS exploit_attempts, latest(_time) AS last_exploit_attempt by vuln_key
  ]
| where isnotnull(exploit_attempts)
| eval risk = "CRITICAL — Vulnerability being actively exploited"
| sort - exploit_attempts
| table Host, CVE, plugin_name, cvss_score, exploit_attempts, last_exploit_attempt, risk

当在关键资产上检测到 KEV 漏洞时发出告警：

index=vulnerability sourcetype="nessus:scan" severity="Critical"
| lookup cisa_kev_lookup.csv cve_id AS CVE OUTPUT kev_status, due_date
| where kev_status="active"
| lookup asset_criticality_lookup.csv ip AS Host OUTPUT criticality
| where criticality IN ("business-critical", "mission-critical")
| table Host, CVE, plugin_name, cvss_score, kev_status, due_date, criticality

步骤 5：构建修复跟踪仪表盘

用于漏洞指标的 Splunk 仪表盘：

-- Open vulnerabilities by severity
index=vulnerability sourcetype="nessus:scan" status="open"
| stats count by severity
| eval order = case(severity="Critical", 1, severity="High", 2, severity="Medium", 3,
                    severity="Low", 4, 1=1, 5)
| sort order

-- SLA compliance tracking
index=vulnerability sourcetype="nessus:scan" status="open"
| eval sla_days = case(
    severity="Critical", 1,
    severity="High", 7,
    severity="Medium", 30,
    severity="Low", 90
  )
| eval days_open = round((now() - first_detected) / 86400)
| eval sla_status = if(days_open > sla_days, "OVERDUE", "Within SLA")
| stats count by severity, sla_status

-- Remediation trend over 90 days
index=vulnerability sourcetype="nessus:scan"
| eval is_open = if(status="open", 1, 0)
| eval is_closed = if(status="fixed", 1, 0)
| timechart span=1w sum(is_open) AS opened, sum(is_closed) AS remediated

步骤 6：自动化修复工单

为高优先级发现自动创建工单：

import requests

servicenow_url = "https://company.service-now.com/api/now/table/incident"
headers = {
    "Content-Type": "application/json",
    "Authorization": f"Bearer {snow_token}"
}

for vuln in vulns:
    if vuln["risk_score"] >= 8.0:
        ticket = {
            "short_description": f"[VULN] {vuln['cve']} — {vuln['plugin_name']} on {vuln['host']}",
            "description": (
                f"Vulnerability: {vuln['plugin_name']}\n"
                f"CVE: {vuln['cve']}\n"
                f"CVSS: {vuln['cvss']}\n"
                f"Host: {vuln['host']}\n"
                f"Asset Criticality: {vuln['asset_criticality']}\n"
                f"CISA KEV: {'YES' if vuln['kev'] else 'NO'}\n"
                f"Risk Score: {vuln['risk_score']}\n"
                f"Remediation SLA: {'24 hours' if vuln['kev'] else '7 days'}"
            ),
            "urgency": "1" if vuln["kev"] else "2",
            "impact": "1" if vuln["asset_criticality"] == "business-critical" else "2",
            "assignment_group": "IT Infrastructure",
            "category": "Vulnerability"
        }
        response = requests.post(servicenow_url, headers=headers, json=ticket)
        print(f"Ticket created: {response.json()['result']['number']}")

关键概念

术语	定义
CVSS	通用漏洞评分系统——漏洞的标准化严重性评级（0-10）
CISA KEV	已知被利用漏洞目录——CISA 维护的已确认存在主动利用行为的漏洞列表
凭证扫描	使用认证访问进行的漏洞扫描，相比仅网络扫描可实现更深入的检测
资产关键性	决定修复优先级的业务影响分类（任务关键、业务关键、标准）
修复 SLA	服务等级协议，定义按严重性允许修复漏洞的最长时间
EPSS	漏洞利用预测评分系统——基于 ML 的概率评分，预测被利用的可能性

工具与系统

• Tenable Nessus / Tenable.io：企业漏洞扫描器，具有 200,000+ 插件检查和合规审计功能
• Qualys VMDR：基于云的漏洞管理，具有资产发现、优先级排序和补丁集成功能
• OpenVAS (Greenbone)：开源漏洞扫描器，带有社区维护的漏洞源
• CISA KEV Catalog：美国政府维护的主动被利用漏洞列表，要求强制修复
• Rapid7 InsightVM：漏洞管理平台，具有实时仪表盘和修复项目跟踪功能

常见场景

• 零日响应：发布新 CVE 时，对受影响软件运行定向扫描，并与 KEV 和漏洞利用数据库交叉比对
• 合规审计准备：生成 PCI DSS 或 HIPAA 漏洞报告，展示扫描覆盖范围和修复状态
• 补丁后验证：重新扫描已修复系统，确认漏洞已关闭并更新跟踪仪表板
• 网络扩展：基础设施新增子网时，按相应策略将其纳入扫描范围
• 第三方风险：在集成前扫描对外资产，验证供应商补丁合规性

输出格式

VULNERABILITY SCAN REPORT — Weekly Summary
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Scan Date:    2024-03-16 02:00 UTC
Scan Scope:   10.0.0.0/16 (1,247 hosts scanned)
Duration:     4h 23m
Coverage:     98.7% (16 hosts unreachable)

Findings:
  Severity     Count    New    CISA KEV
  Critical     23       5      3
  High         187      34     12
  Medium       892      78     0
  Low          1,456    112    0
  Info         3,891    201    0

Top Priority (P1 — 24hr SLA):
  CVE-2024-21762  FortiOS RCE           3 hosts   KEV: YES
  CVE-2024-1709   ConnectWise RCE       1 host    KEV: YES
  CVE-2024-3400   Palo Alto PAN-OS RCE  2 hosts   KEV: YES

SLA Compliance:
  Critical: 82% within SLA (4 overdue)
  High:     91% within SLA (17 overdue)
  Medium:   88% within SLA (107 overdue)

Tickets Created: 39 (ServiceNow)