What Is DDoS Prevention?
Distributed Denial of Service (DDos) is a type of cyberattack in which attackers bombard an organization’s systems with fake traffic, disrupting service for legitimate users. They are typically carried out via botnets, massive groups of compromised devices under the attacker’s control.
DDoS prevention involves a mix of strategic planning, technical solutions, and continuous monitoring to ensure the highest level of security. It’s not just about blocking denial of service traffic; it’s about effectively differentiating between legitimate and illegitimate traffic, ensuring the smooth functioning of services even under attack. With the increasing volume and sophistication of DDoS attacks, prevention has become more crucial than ever.
Types of DDoS Attacks
In order to plan an effective prevention strategy, you must be aware of the main types of DDoS attacks.
Volume-Based Attacks
Volume-Based attacks are among the most common forms of DDoS attacks. They aim to overwhelm a network’s bandwidth by flooding it with immense volumes of useless data. This renders the network unable to handle legitimate requests, causing a denial of service.
These attacks often employ botnets to generate the enormous volumes of traffic required. The size of a volume-based attack is measured in bits per second (Bps), and they can range from a few gigabits to several terabits per second.
Protocol Attacks
Protocol attacks, also known as state-exhaustion attacks, exploit vulnerabilities in a server’s resources rather than its bandwidth. These attacks target specific areas of a server, such as the firewall or load balancer, with the aim of consuming their capacity.
A popular form of protocol attack is the SYN flood, where an attacker initiates a connection with a server but never completes the handshake process. This leaves the server’s resources tied up, waiting for a response that never comes.
Application Layer Attacks
Application Layer Attacks, also known as Layer 7 attacks, target the layer where websites operate. These attacks mimic normal traffic patterns, making them hard to identify and mitigate. They aim to exhaust server resources by sending a large number of requests that appear legitimate, causing the server to crash.
Unlike volume-based and protocol attacks, application layer attacks require less bandwidth to execute effectively. However, they can be just as, if not more, damaging due to their ability to fly under the radar of many detection systems.
Ransom DDoS (RDDoS)
Ransom DDoS, or RDDoS, is a type of DDoS attack where the attacker threatens to disrupt a network unless a ransom is paid. This type of attack can be particularly damaging as it combines the destructive potential of a DDoS attack with the financial implications of a ransom demand.
RDDoS attacks are becoming increasingly common, and they can be particularly challenging to deal with. The threat of an impending DDoS attack can be enough to cause significant disruption, even if the attack itself never materializes.
Advanced Persistent DoS (APDoS)
APDoS attacks represent a new level of sophistication in DDoS attacks. They involve the constant and relentless targeting of a system over an extended period, often changing tactics to circumvent security measures.
APDoS attacks can combine multiple attack vectors, including the ones mentioned above, to keep the target systems under constant pressure. These attacks require a high level of coordination and resources, often indicating the involvement of organized cybercriminal groups.
Distributed Reflection Denial of Service (DRDoS)
DRDoS attacks use a technique known as reflection to amplify the amount of traffic directed at a target. In this type of attack, an attacker sends requests to a large number of computers, using the target’s IP address as the source. These computers, unknowingly, send their responses to the target, flooding it with traffic.
The power of DRDoS attacks lies in their ability to multiply the impact of an attack, using the resources of unwitting third-party systems. This amplification makes DRDoS attacks particularly potent and challenging to mitigate.
DDoS Prevention Technologies and Techniques
Here are some of the tools and techniques that can help organizations prevent DDoS attacks.
Network Firewalls
Network firewalls serve as the first line of defense in DDoS Prevention. They monitor incoming and outgoing network traffic and decide whether to allow or block specific traffic based on predefined security rules. In the context of DDoS prevention, firewalls can help filter out malicious traffic or limit the rate of incoming traffic. However, firewalls on their own are not sufficient to block large-scale DDoS attacks, because they cannot scale to process the sheer volume of requests.
WAFs
Web Application Firewalls (WAFs) are a specialized type of firewall designed specifically to protect web applications from threats that traditional firewalls may not detect. WAFs are particularly effective in preventing application-layer DDoS attacks, which target specific aspects of a web application rather than simply overwhelming the network with traffic. However, like traditional firewalls, WAFs are ineffective against large-scale DDoS due to their limited scalability.
Intrusion Prevention Systems (IPS)
Intrusion Prevention Systems (IPS) are network security appliances that monitor network and/or system activities for malicious activity. They can identify and mitigate threats in real-time, providing an additional layer of protection against DDoS attacks. IPS systems are often used in conjunction with firewalls and other security measures. Similar to firewalls and WAFs, IPS have limited scalability and so can only be effective against small-scale DoS attacks.
Rerouting Traffic with Content Delivery Networks (CDN)
Content Delivery Networks (CDN) are another effective tool in preventing DDoS attacks. A CDN is a network of servers distributed across various locations. When a user makes a request to a website that is part of a CDN, the request is redirected to the server closest to the user. This reduces the load on the website’s server and improves the website’s performance.
In the context of DDoS prevention, CDNs can absorb and distribute the traffic associated with a DDoS attack, thereby preventing the targeted server from being overwhelmed. They can also identify and filter out malicious traffic, thus providing an additional layer of security.
Rerouting Traffic with Content Delivery Networks (CDN)
Content Delivery Networks (CDN) are another effective tool in preventing DDoS attacks. A CDN is a network of servers distributed across various locations. When a user makes a request to a website that is part of a CDN, the request is redirected to the server closest to the user. This reduces the load on the website’s server and improves the website’s performance.
In the context of DDoS prevention, CDNs can absorb and distribute the traffic associated with a DDoS attack, thereby preventing the targeted server from being overwhelmed. They can also identify and filter out malicious traffic, thus providing an additional layer of security.
Blackholing and Sinkholing
Blackholing and sinkholing are techniques used to divert malicious traffic away from the target network. In blackholing, all traffic to the attacked IP address is dropped, effectively making it disappear. Sinkholing, on the other hand, redirects traffic to a ‘sinkhole’ where it can be analyzed and filtered before being allowed to proceed to the target network.
Backhaul and sinkholing are a double edged sword, because while they can be effective against DDoS, they can also prevent legitimate users from accessing an organization’s web services, even after the DDoS attack has ended.
Anomaly and Behavior-Based Detection
Anomaly and behavior-based detection systems monitor network traffic patterns and identify any unusual or suspicious activity. These systems leverage machine learning algorithms to learn what normal network behavior looks like and can detect deviations that may indicate a DDoS attack. This proactive approach allows for early detection and mitigation of DDoS attacks. However, while behavioral analysis can be useful for detecting DDoS attacks, on their own they cannot stop DDoS attacks.
Cloud-Based DDoS Prevention Services
Cloud-based DDoS Prevention Services offer a scalable and flexible solution for DDoS protection. They leverage the vast resources of the cloud to absorb and diffuse DDoS traffic before it reaches the target network. This approach not only protects the network from attack but also ensures that legitimate traffic can continue to flow unhindered. Cloud-based DDoS protection services are possibly the only reliable defense against large-scale DDoS attacks.
5 Best Practices for Preventing DDoS Attacks
The following best practices will help you effectively prepare for DDoS prevention.
1. Create a DDoS Response Plan
A well-formulated DDoS response plan is a critical component of DDoS prevention. This plan should outline the steps to be taken in the event of an attack, including communication strategies, roles and responsibilities, and technical measures to mitigate the attack’s impact.
The plan should be comprehensive, covering all aspects of your organization’s response to an attack, from technical to PR. It should also be regularly reviewed and updated to reflect the evolving nature of DDoS threats. Having a clear, well-rehearsed plan in place can significantly reduce the time it takes to respond to an attack, minimizing its impact.
2. Focus on Early Detection
Identifying the signs of a DDoS attack in its early stages can make a significant difference in minimizing its impact. Common symptoms include a sudden slowdown in network performance, unavailability of a particular website, or an overwhelming increase in the number of spam emails. These are often the first red flags of a DDoS attack.
It’s essential to understand that these symptoms do not definitively confirm a DDoS attack, as they could result from other technical issues. However, if these symptoms persist or intensify, it becomes more likely that you’re under attack. Early detection is crucial in DDoS prevention, as it allows your team to respond quickly and limit the damage.
3. Continuously Monitor Network Traffic
Continuous monitoring of network traffic is a crucial part of DDoS prevention. This involves keeping a close eye on your network’s traffic patterns, looking for any unusual or suspicious activity that could indicate a DDoS attack.
Monitoring can be done using various tools and techniques, from simple network traffic analysis tools to sophisticated systems based on behavioral analysis that can detect even the most subtle signs of an impending attack.
4. Have Server Redundancy
Server redundancy is another effective strategy for DDoS prevention. This involves having multiple servers on standby to take over if your primary server becomes overloaded due to a DDoS attack. This ensures that your services remain available even under attack, minimizing downtime and disruption to your users.
Server redundancy is typically achieved through load balancing, where network traffic is distributed across multiple servers to ensure none becomes overloaded. This not only enhances your system’s ability to handle large volumes of traffic but also provides an additional layer of protection against DDoS attacks.
5. Leverage the Cloud to Prevent DDoS Attacks
Finally, leveraging the cloud can be a highly effective way to prevent DDoS attacks. Cloud-based DDoS prevention services can handle much larger volumes of traffic than a single server, making them an ideal solution for protecting against large-scale DDoS attacks.
These services typically work by absorbing and diffusing the traffic associated with a DDoS attack, ensuring that your network or server is not overwhelmed. They also offer advanced traffic filtering capabilities, allowing them to effectively distinguish between legitimate and malicious traffic.
Imperva Cloud-Based DDoS Prevention
Imperva guards you against the largest, most complex DDoS attacks of today with full protection at the edge.
Our transparent mitigation ensures your web visitors, and your business, will never suffer during an attack.
With multi-layered approach to DDoS mitigation we secure all your assets, wherever they are, on premises or in the cloud – whether you’re hosted in AWS, Microsoft Azure, or Google Public Cloud.
