Implementing Cloud Waf Rules

# AWS WAF: Create Web ACL with AWS Managed Rules
aws wafv2 create-web-acl \
  --name production-waf \
  --scope REGIONAL \
  --default-action '{"Allow": {}}' \
  --visibility-config '{
    "SampledRequestsEnabled": true,
    "CloudWatchMetricsEnabled": true,
    "MetricName": "production-waf"
  }' \
  --rules '[
    {
      "Name": "AWSManagedRulesCommonRuleSet",
      "Priority": 1,
      "Statement": {
        "ManagedRuleGroupStatement": {
          "VendorName": "AWS",
          "Name": "AWSManagedRulesCommonRuleSet"
        }
      },
      "OverrideAction": {"Count": {}},
      "VisibilityConfig": {
        "SampledRequestsEnabled": true,
        "CloudWatchMetricsEnabled": true,
        "MetricName": "CommonRuleSet"
      }
    },
    {
      "Name": "AWSManagedRulesSQLiRuleSet",
      "Priority": 2,
      "Statement": {
        "ManagedRuleGroupStatement": {
          "VendorName": "AWS",
          "Name": "AWSManagedRulesSQLiRuleSet"
        }
      },
      "OverrideAction": {"Count": {}},
      "VisibilityConfig": {
        "SampledRequestsEnabled": true,
        "CloudWatchMetricsEnabled": true,
        "MetricName": "SQLiRuleSet"
      }
    },
    {
      "Name": "AWSManagedRulesKnownBadInputsRuleSet",
      "Priority": 3,
      "Statement": {
        "ManagedRuleGroupStatement": {
          "VendorName": "AWS",
          "Name": "AWSManagedRulesKnownBadInputsRuleSet"
        }
      },
      "OverrideAction": {"Count": {}},
      "VisibilityConfig": {
        "SampledRequestsEnabled": true,
        "CloudWatchMetricsEnabled": true,
        "MetricName": "KnownBadInputs"
      }
    }
  ]'

# Rate limiting rule for login endpoint (100 requests per 5 minutes per IP)
aws wafv2 update-web-acl \
  --name production-waf \
  --scope REGIONAL \
  --id <web-acl-id> \
  --lock-token <lock-token> \
  --default-action '{"Allow": {}}' \
  --rules '[
    {
      "Name": "RateLimitLogin",
      "Priority": 0,
      "Statement": {
        "RateBasedStatement": {
          "Limit": 100,
          "AggregateKeyType": "IP",
          "ScopeDownStatement": {
            "ByteMatchStatement": {
              "FieldToMatch": {"UriPath": {}},
              "PositionalConstraint": "STARTS_WITH",
              "SearchString": "/api/auth/login",
              "TextTransformations": [{"Priority": 0, "Type": "LOWERCASE"}]
            }
          }
        }
      },
      "Action": {"Block": {"CustomResponse": {"ResponseCode": 429}}},
      "VisibilityConfig": {
        "SampledRequestsEnabled": true,
        "CloudWatchMetricsEnabled": true,
        "MetricName": "RateLimitLogin"
      }
    }
  ]'

# AWS WAF: Geo-blocking rule
# Block countries not in the allowed list
aws wafv2 create-ip-set \
  --name blocked-ips \
  --scope REGIONAL \
  --ip-address-version IPV4 \
  --addresses "198.51.100.0/24" "203.0.113.0/24"

# Add Amazon IP Reputation rule
# AWSManagedRulesAmazonIpReputationList blocks IPs flagged by AWS threat intelligence

# Enable WAF logging to S3
aws wafv2 put-logging-configuration \
  --logging-configuration '{
    "ResourceArn": "arn:aws:wafv2:us-east-1:123456789012:regional/webacl/production-waf/id",
    "LogDestinationConfigs": ["arn:aws:s3:::waf-logs-bucket"],
    "RedactedFields": [{"SingleHeader": {"Name": "authorization"}}]
  }'

# Query WAF logs with Athena to find false positives
# Find rules triggered most frequently for legitimate traffic
cat << 'EOF' > waf-analysis.sql
SELECT
  terminatingRuleId,
  httpRequest.uri,
  httpRequest.httpMethod,
  COUNT(*) as block_count
FROM waf_logs
WHERE action = 'BLOCK'
  AND timestamp > date_add('day', -7, now())
GROUP BY terminatingRuleId, httpRequest.uri, httpRequest.httpMethod
ORDER BY block_count DESC
LIMIT 20
EOF

# Exclude specific rule from managed rule set that causes false positives
# Example: Exclude SizeRestrictions_BODY for file upload endpoint
aws wafv2 update-web-acl \
  --name production-waf \
  --scope REGIONAL \
  --id <web-acl-id> \
  --lock-token <lock-token> \
  --rules '[{
    "Name": "AWSManagedRulesCommonRuleSet",
    "Priority": 1,
    "Statement": {
      "ManagedRuleGroupStatement": {
        "VendorName": "AWS",
        "Name": "AWSManagedRulesCommonRuleSet",
        "ExcludedRules": [{"Name": "SizeRestrictions_BODY"}]
      }
    },
    "OverrideAction": {"None": {}},
    "VisibilityConfig": {
      "SampledRequestsEnabled": true,
      "CloudWatchMetricsEnabled": true,
      "MetricName": "CommonRuleSet"
    }
  }]'

# Change OverrideAction from Count to None (use rule group's default Block action)
# Update each managed rule group from {"Count": {}} to {"None": {}}
# Monitor CloudWatch metrics for sudden changes in blocked request volume