Triagem de Incidentes de Segurança com Playbooks de Resposta a Incidentes

Quando Usar

• Novo alerta de segurança recebido de SIEM, EDR ou outras fontes de detecção
• Analista de SOC precisa determinar se um alerta é um positivo real que requer resposta
• Incidente precisa de classificação de severidade e atribuição de equipe
• Múltiplos incidentes concorrentes exigem priorização
• Regras de triagem automatizadas precisam de validação ou ajuste

Pré-requisitos

• Plataforma SIEM com correlação de alertas (Splunk, Elastic, QRadar, Sentinel)
• Biblioteca de playbooks de resposta a incidentes (por tipo de incidente)
• Matriz de classificação de severidade aprovada pelo CISO
• Procedimentos de rotação de plantão e escalonamento
• Sistema de tickets para rastreamento de incidentes (ServiceNow, Jira, TheHive)
• Feeds de inteligência de ameaças para enriquecimento de IOCs

Fluxo de Trabalho

Etapa 1: Receber e Reconhecer Alerta

# Query Splunk for new critical/high severity alerts
index=notable status=new severity IN ("critical","high")
| table _time, rule_name, src, dest, severity, description
| sort -_time

# Query TheHive for new cases
curl -s -H "Authorization: Bearer $THEHIVE_API_KEY" \
  "https://thehive.local/api/v1/query?name=list-alerts" \
  -H "Content-Type: application/json" \
  -d '{"query":[{"_name":"listAlert"},{"_name":"filter","_field":"status","_value":"New"}]}'

# Acknowledge alert in SIEM to prevent duplicate triage
curl -X POST "https://splunk.local:8089/services/notable_update" \
  -H "Authorization: Bearer $SPLUNK_TOKEN" \
  -d "ruleUIDs=$RULE_UID&status=1&comment=Triage+initiated+by+analyst"

Etapa 2: Enriquecer Dados do Alerta

# Enrich source IP with VirusTotal
curl -s "https://www.virustotal.com/api/v3/ip_addresses/$SRC_IP" \
  -H "x-apikey: $VT_API_KEY" | jq '.data.attributes.last_analysis_stats'

# Check IP reputation with AbuseIPDB
curl -s "https://api.abuseipdb.com/api/v2/check?ipAddress=$SRC_IP&maxAgeInDays=90" \
  -H "Key: $ABUSEIPDB_KEY" -H "Accept: application/json" | jq '.data'

# Enrich file hash with threat intelligence
curl -s "https://www.virustotal.com/api/v3/files/$FILE_HASH" \
  -H "x-apikey: $VT_API_KEY" | jq '.data.attributes.last_analysis_stats'

# Query internal asset database for affected systems
curl -s "https://cmdb.local/api/assets?ip=$DEST_IP" \
  -H "Authorization: Bearer $CMDB_TOKEN" | jq '.asset_criticality, .owner, .environment'

Etapa 3: Classificar Tipo de Incidente

# Map alert to incident category using playbook lookup
# Categories: Malware, Phishing, Unauthorized Access, Data Exfiltration,
# DoS/DDoS, Insider Threat, Ransomware, Account Compromise, Web Attack

# Check if alert matches known playbook trigger conditions
grep -i "$ALERT_SIGNATURE" /opt/ir/playbooks/trigger_conditions.yaml

# Determine incident type from MITRE ATT&CK technique
curl -s "https://attack.mitre.org/api/techniques/$TECHNIQUE_ID" | jq '.name, .tactic'

Etapa 4: Atribuir Nível de Severidade

# Severity matrix factors:
# 1. Asset criticality (Critical/High/Medium/Low)
# 2. Data sensitivity (PII/PHI/PCI/Confidential/Public)
# 3. Number of affected systems
# 4. Active vs historical threat
# 5. Confirmed vs suspected compromise

# Automated severity calculation
python3 -c "
severity_score = 0
# Asset criticality: Critical=4, High=3, Medium=2, Low=1
severity_score += 4  # Critical server
# Data sensitivity: PII/PHI=4, PCI=3, Confidential=2, Public=1
severity_score += 3  # PCI data
# Scope: Enterprise=4, Department=3, Single system=2, Single user=1
severity_score += 2  # Single system
# Threat status: Active=4, Recent=3, Historical=2, Potential=1
severity_score += 4  # Active threat

if severity_score >= 12: print('CRITICAL - P1')
elif severity_score >= 9: print('HIGH - P2')
elif severity_score >= 6: print('MEDIUM - P3')
else: print('LOW - P4')
print(f'Score: {severity_score}/16')
"

Etapa 5: Selecionar e Iniciar Playbook

# Carregar playbook apropriado com base no tipo de incidente
cat /opt/ir/playbooks/ransomware_playbook.yaml
cat /opt/ir/playbooks/phishing_playbook.yaml
cat /opt/ir/playbooks/unauthorized_access_playbook.yaml

# Criar ticket de incidente no TheHive
curl -X POST "https://thehive.local/api/v1/case" \
  -H "Authorization: Bearer $THEHIVE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "title": "IR-2024-XXX: [Tipo de Incidente] - [Breve Descrição]",
    "description": "Resumo da triagem e descobertas iniciais",
    "severity": 3,
    "tlp": 2,
    "pap": 2,
    "tags": ["ransomware", "triagem-completa"],
    "customFields": {
      "playbook": {"string": "ransomware_v2"},

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