DDoS Mitigation for High-Traffic Sites

DDoS Mitigation for High-Traffic Sites

High-profile websites attract sophisticated DDoS attacks that require multi-layered defense strategies:

#!/usr/bin/env python3
# Advanced DDoS mitigation system

import asyncio
import aioredis
import numpy as np
from collections import defaultdict
import ipaddress

class DDoSMitigationSystem:
    def __init__(self):
        self.redis_pool = None
        self.attack_patterns = {
            'syn_flood': {'threshold': 1000, 'window': 60},
            'http_flood': {'threshold': 5000, 'window': 60},
            'slowloris': {'threshold': 100, 'window': 300},
            'amplification': {'threshold': 10000, 'window': 60}
        }
        
    async def initialize(self):
        """Initialize Redis connection for distributed state"""
        self.redis_pool = await aioredis.create_redis_pool(
            'redis://localhost',
            minsize=5,
            maxsize=10
        )
    
    async def analyze_traffic_pattern(self, packet_data):
        """Analyze traffic for DDoS patterns"""
        
        source_ip = packet_data['source_ip']
        packet_type = packet_data['type']
        timestamp = packet_data['timestamp']
        
        # Update counters in Redis
        key = f"ddos:{packet_type}:{source_ip}"
        await self.redis_pool.incr(key)
        await self.redis_pool.expire(key, 300)  # 5 minute expiry
        
        # Check against thresholds
        count = await self.redis_pool.get(key)
        if count and int(count) > self.attack_patterns.get(packet_type, {}).get('threshold', float('inf')):
            return await self.mitigate_attack(source_ip, packet_type)
        
        return None
    
    async def mitigate_attack(self, source_ip, attack_type):
        """Implement mitigation strategies"""
        
        mitigation_action = {
            'source_ip': source_ip,
            'attack_type': attack_type,
            'actions': []
        }
        
        # Add to blacklist
        await self.redis_pool.sadd('ddos:blacklist', source_ip)
        mitigation_action['actions'].append('blacklisted')
        
        # Null route at edge routers
        if self.is_severe_attack(attack_type):
            await self.null_route_ip(source_ip)
            mitigation_action['actions'].append('null_routed')
        
        # Enable challenged mode for subnet
        subnet = str(ipaddress.ip_network(f"{source_ip}/24", strict=False))
        await self.enable_challenge_mode(subnet)
        mitigation_action['actions'].append('challenge_enabled')
        
        return mitigation_action
    
    async def enable_challenge_mode(self, subnet):
        """Enable JavaScript/CAPTCHA challenges for subnet"""
        
        # Add to challenge list
        await self.redis_pool.sadd('ddos:challenge_subnets', subnet)
        await self.redis_pool.expire('ddos:challenge_subnets', 3600)  # 1 hour
        
        # Update edge configuration
        edge_config = {
            'subnet': subnet,
            'challenge_type': 'js_challenge',
            'duration': 3600
        }
        
        await self.update_edge_configuration(edge_config)