A Distributed Denial of Service (DDoS) attack is one of the biggest threats facing websites today. DDoS attacks aim to overwhelm a website’s infrastructure by flooding it with bogus traffic from multiple sources, rendering the site inaccessible to legitimate users. If your website goes down due to a DDoS attack, you stand to lose revenue, customers, and credibility. Implementing proper DDoS protection is essential to keep your website secure, online, and running smoothly.
This article provides a comprehensive overview of DDoS attacks and how to safeguard your website against them. We will cover what a DDoS attack is, common DDoS attack types and tools, the business impact of DDoS attacks, DDoS protection best practices, and solutions available to mitigate DDoS threats. With the right DDoS protection strategy, you can protect your website from being taken down by the crippling effects of a distributed denial of service attack.
What is a DDoS Attack?
A distributed denial of service (DDoS) attack is a malicious attempt to disrupt normal website traffic and make it unavailable to legitimate users. The goal is to overwhelm and crash the website’s servers by flooding it with more requests than it can handle. This is achieved by using multiple compromised devices to target the website simultaneously.
Unlike typical denial of service attacks from a single source, DDoS attacks come from many distributed sources at the same time. Attackers exploit vulnerabilities in IoT devices like routers, webcams, and digital video recorders to infect them with malware. They then control these devices remotely as part of a botnet, which allows them to coordinate large scale attacks on high value targets.
When a DDoS attack occurs, the website is barraged with junk traffic that occupies all available resources on the server. As a result, the website is unable to respond to real users trying to access pages or use services. If the attack is large enough, the website may become completely unreachable or crash entirely. This can cost businesses severe financial damages and loss of reputation.
Common DDoS Attack Tools and Tactics
There are several methods cybercriminals use to execute DDoS assaults and some of the common tools and tactics include:
Volume-based attacks aim to consume all available bandwidth leading to the victim’s network or servers. Some examples include:
- UDP floods – where a botnet sends a large number of UDP packets to random ports on the victim system. This renders the network unavailable.
- ICMP floods – the attacker overwhelms the victim with ICMP echo requests (pings) from spoofed IP addresses.
- SYN floods – the attacker sends a flood of TCP SYN requests to the server but never responds to the SYN-ACK replies. This leaves ports unavailable for legitimate users.
These attacks target inherent weaknesses in network protocols themselves. Examples are:
- Smurf Attack – exploiting ICMP protocols by spoofing the victim’s IP when sending large ICMP requests.
- Ping of Death – sending malformed or oversized ping packets that crash the system.
- teardrop – fragmented packets that overwhelm TCP/IP reassembly mechanisms.
Application Layer Attacks
These attacks target web servers and applications directly using less traffic but well timed requests:
- HTTP flooding – Bombarding sites with valid HTTP GET or POST requests
- Zero-day DDoS attacks – Exploiting vulnerabilities in applications or operating systems to crash servers or processes.
- Slowloris – Opening numerous connections to the web server and holding them open as long as possible.
- DNS amplification – Using open DNS resolvers to overwhelm a DNS server with monstrous DNS responses.
Permanent Denial of Service Attacks
These rare but devastating attacks can destroy hardware and wipe out data. Examples are:
- Brute force attacks – Guessing weak credentials repeatedly until systems are locked.
- Viruses or worms – Malicious software that destroys firmware, applications, or the operating system.
- Phlashing – Reprogramming a computer’s firmware rendering it inoperable.
Major DDoS Attack Tools
Some of the common DDoS tools used in major cyber attacks are:
LOIC (Low Orbit Ion Cannon)
A popular DDoS tool that allows users to control multiple compromised systems to carry out DDoS floods. Generally uses TCP, UDP, or HTTP floods.
HOIC (High Orbit Ion Cannon)
A more powerful version of LOIC that allows simultaneous attacks from multiple users through a centralized control server. Often used by hacktivist groups like Anonymous.
One of the earliest DDoS tools from the late 90s. Uses UDP flooding via master-slave botnet architecture. Infamous for taking down major sites like eBay, Amazon, etc.
Updated version of Trinoo capable of TCP, ICMP, and UDP attacks using encrypted communications between bots and handlers.
DDoS tool that preceded modern botnets. Sends all requests through the master bot making it harder to block based on source IP.
Powerful descendant of the Tribe Flood Network capable of complex DDoS attacks like SYN/ UDP/ ICMP floods, Smurf attacks, etc.
emerged in 2018 with amplification capabilities using vulnerable memcached servers to increase attack bandwidth by over 50,000 times.
Motivations Behind DDoS Attacks
Understanding why attackers unleash DDoS attacks gives better insight into how to fully protect against them. Some motivations include:
Cybercriminals can profit from DDoS in different ways:
- Ransom DDoS – Taking down sites and demanding ransom to stop attacks.
- Competitor takedowns – Attackers paid to cripple business competitors.
- Cryptocurrency mining – Using botnets to mine cryptocurrency on infected systems.
Politically or socially motivated DDoS attacks against government and commercial entities by hacktivist groups like Anonymous.
Disgruntled employees or customers with a vendetta can launch attacks against companies. Ex-gamers can DDoS gaming sites after being banned.
Rival nations and intelligence agencies use DDoS to take down critical infrastructure and government servers of adversaries.
DDoS used to divert IT resources while more serious hacking attempts are made on the network.
Impact of DDoS Attacks on Businesses
The business impact of DDoS attacks can be severe, leading to:
Revenue and Productivity Losses
When a site is down, sales, customer access, and workflow grind to a halt. This directly hits the bottom line.
Attacked sites lose existing and potential customers who see them as unreliable and insecure.
Loss of Data
Permanent denial of service attacks can lead to data destruction and integrity loss.
DDoS caused downtimes may breach service agreements for online services.
Emergency Response Costs
Substantial costs are incurred in emergency response to mitigate attacks and manage damage.
Post-attack Disaster Recovery
Days or weeks of disruption can occur while rebuilding systems, restoring data, and resuming normal operations.
Best Practices for DDoS Protection
Keeping your website safe from DDoS requires focused efforts on prevention, monitoring, and mitigation. Key best practices include:
Network and Web Server Hardening
Eliminate vulnerabilities, enable latest security features of network devices, web apps, DNS, etc.
Scale out with load balancing, alternate data centers, geoblocking, caching, and bandwidth overprovisioning.
24/7 monitoring using SIEM, analytics, and traffic profiling to detect anomalies indicating DDoS activity.
Have an incident response plan with coordination between your network, security and executive teams.
Firewalls and Rate Limiting
Use next-gen firewalls and web app firewalls capable of signature-based and behavioral DDoS protection. Configure hardware rate limiting.
Advertise false routes to absorb DDoS traffic away from data centers. Useful for network layer protection.
Cloud-based Scrubbing Services
Route traffic to cloud scrubbing centers which filter DDoS traffic before passing clean traffic to your infrastructure.
Whitlisting IP Ranges
Where possible, accept traffic only from known IP address ranges while blocking all other traffic.
Educate end-users to identify social engineering attempts, use strong passwords, keep software updated.
On-Premise DDoS Mitigation Solutions
There are several on-premise solutions available to protect against DDoS attacks:
DDoS Resistant Hardware
Enterprise grade routers, load balancers, and DDoS mitigation appliances specialized in filtering attack traffic while maintaining availability.
Web Application Firewalls
WAFs inspect HTTP traffic for DDoS patterns and malicious payloads. Rules can block IPS, malformed requests etc.
Session Border Controllers
SBCs are deployed in VoIP infrastructures to prevent call flooding and service abuse.
DDoS Mitigation Software
Software solutions like firewalls and intrusion prevention systems use thresholds and signatures to detect anomalies and block attacks.
Threat Intelligence Feeds
Feeds containing lists of known bad IP addresses, botnet hosts, and geospatial sources of attacks let you block DDoS traffic preemptively.
Authoritative DNS servers can detect anomalies in DNS traffic and drop amplification/reflection attacks using rate limiting.
Cloud-based DDoS Protection
In addition to on-premise solutions, cloud-based DDoS protection offers several benefits:
Easy and Rapid Deployment
Cloud DDoS services require less hardware, configuration and setup time. Easy to add on to existing infrastructure.
No large capital expenditure needed for hardware mitigation devices. Pay only for actual usage rather than provisioning for peak traffic.
Scalability on Demand
Cloud DDoS services absorb the impact of any attack size due to massive bandwidth and mitigation capacities.
Real-time monitoring provides actionable insights into traffic patterns, attack characteristics, and mitigation effectiveness.
Around the Clock Expert Support
24/7 support from cloud providers to assist during attacks and tweak configurations.
Cloud services offer continuous protection regardless of network, server or application Layer 7 attacks.
Holistic safeguards against network, transport, and application Layer DDoS attacks.
Choosing the Right DDoS Mitigation Service
Key criteria for selecting a cloud-based DDoS protection service include:
Look for protection against Layer 3, 4 and 7 DDoS attacks of all sizes and vectors using scrubbing centers close to your infrastructure.
Service should provide distributed scrubbing centers covering North America, Europe, Asia and other regions you operate in.
Must detect anomalous traffic and attacks reliably without false positives that block legitimate users.
Time to Mitigate
The quicker the solution can detect and nullify attacks the better. Sub 10 second mitigation is ideal.
Dashboard for monitoring live traffic, configuring policies, reviewing attack analytics. Mobile app is a plus.
24/7 support via phone, email and chat in case issues arise during an attack.
Subscription plans based on bandwidth use offer predictable costs rather than usages fees that can inflate during large attacks.
Hybrid and Multi-CDN Options
Support for integrating on-premise hardware and hybrid DDoS protection. Ability to load balance across multiple content delivery networks.
Comparing Top Cloud DDoS Mitigation Providers
Some prominent cloud scrubbing and DDoS protection services to consider are:
A content delivery network that offers a range of web performance and security solutions including DDoS protection and WAF.
Provides DDoS defense via its globally distributed intelligent platform and vulnerability assessment.
Offers DDoS protection using scrubbing centers and targeted filtering of bad traffic.
UltraDNS service absorbs DDoS attacks while load balancing and failover maintain uptime.
Silverline scrubbing network claims ability to mitigate attacks within 30 seconds.
Cloud proxy service blocks Layer 7 attacks targeting web applications using negative security models.
Provides behavioral analysis using big data algorithms to protect against zero day DDoS threats.
The Importance of DDoS Resilience Testing
In addition to having a mitigation service, it is vital to test the DDoS resiliency of your infrastructure periodically. This is done by simulating attacks of different types and sizes against your website in a controlled manner. The benefits of resilience testing include:
Validating Effectiveness of Defenses
Testing demonstrates how your existing tools and services withstand different DDoS attack scenarios.
Improving Incident Response
Tests your team’s speed and coordination in detecting and reacting to DDoS incidents.
Finds weaknesses in DDoS protection that can then be remediated before real attacks exploit them.
Regulators and customers may require evidence of ability to withstand DDoS attacks.
Peace of Mind
Knowing your site survives simulated worst case attacks gives confidence you can weather real ones.
DDoS threats are one of the most difficult challenges facing websites and online services today. The financial, operational and reputational damages that can result from DDoS attacks make comprehensive protection vital. By understanding DDoS attack methods, implementing best practices, and utilizing a cloud scrubbing service, businesses can cost-effectively safeguard their websites from the crippling effects of DDoS assaults. With proper planning and the right solutions in place, you can maintain the high availability and performance your users expect while thwarting denial of service attempts.