A Distributed Denial of Service (DDoS) attack is a malicious attempt to disrupt the normal functioning of a targeted server, network, or website by overwhelming it with internet traffic.
A DDoS attack involves an intricate web of computers, tablets, and other devices, which have been infected with malware, allowing them to be puppeteered by an attacker. These individual devices are referred to as bots and a group of them is known as a botnet.
The immense volume of requests caused by the botnet, overwhelms the target’s infrastructure, making it unable to respond to legitimate traffic, causing slowdowns or complete service outages. To put it simply, if you imagine your business as a storefront, a DDoS attack is the equivalent of an angry mob swarming the building, stopping real customers from seeing your wares.
What is the goal of a DDoS attack?
Like most cyber threats, the first goal of a DDoS attack is to cause destruction. By overwhelming a website with excessive traffic, and denying legitimate users access, attackers can cause financial losses, disrupt business operations, and damage their reputation.
Then, once the damage is done and chaos is running amok, the second goal of a DDoS attack comes into play – extortion. Attackers will lock businesses out of their operations until they receive payment. A quick tip – never pay a ransom. 80% of companies that paid a ransom were attacked again, and 40% paid a second time.
In some rarer cases, the goal of a DDoS attack might be distraction. Attackers can use these DDoS attacks as a distraction while they attempt to infiltrate the target’s network for other malicious purposes, such as data theft or the installation of malware.
How can companies protect themselves from DDoS attacks?
It is essential that businesses adopt a multi-layered security approach in order to combat DDoS attacks. An important first step is implementing a robust firewall and intrusion detection systems (IDS) to identify and block malicious traffic.
Once malicious traffic is identified, a content delivery network (CDN) can help distribute traffic across multiple servers, reducing the impact of an attack on a single server. Rate limiting is also effective as it can prevent traffic overload by limiting the number of requests from each IP address.
Additionally, businesses can engage in automated penetration testing services that simulate attacks to fix vulnerabilities without any downtime. Regular network monitoring is essential, but it also has to be backed up with cybersecurity training for staff so they don’t puncture any holes in an otherwise airtight security setup.
Lastly, a quick and easy win is keeping software and systems up to date so it reduces vulnerabilities that attackers may exploit.
What are some common types of DDoS attacks?
DDoS attacks come in three variants: application layer attacks, protocol attacks, and volumetric attacks. Application layer attacks target specific applications or services by exploiting vulnerabilities in the application layer of the network stack. Protocol attacks exploit vulnerabilities in network protocols to disrupt a target’s infrastructure. Volumetric attacks use brute force to flood a target with data packets to consume bandwidth and resources.
Application layer attacks
Application layer attacks (Layer 7) target the topmost layer of the OSI model, aiming to exhaust server resources by overwhelming specific services or applications.
These attacks mimic legitimate user behaviour, making them harder to detect. Their goal is to disrupt a website or service, causing slowdowns or crashes. Since they require fewer resources than other types of DDoS attacks, they are more difficult to defend against, especially considering the amount of resources it takes to mitigate an application layer attack.
Mimicked user browsing
Mimicked user browsing is a type of application layer attack that involves sending requests that resemble normal web traffic. By simulating human browsing behaviour, the attacker’s botnet can generate numerous page loads and form submissions, forcing the server to handle more tasks than it can manage, which eventually leads to crashes or service delays.
HTTP(/s) flooding
HTTP(s) flooding involves overwhelming a server with a flood of HTTP or HTTPS requests, which causes it to allocate all its resources to processing these requests. Attackers typically send repeated GET or POST requests, which overload the server, rendering the website inaccessible to legitimate users and depleting available resources.
Protocol attacks
Protocol attacks exploit weaknesses in the protocols used by the network infrastructure. They overwhelm network resources by consuming bandwidth and exhausting resources such as connection state tables, causing interruptions to services. Examples include Ping of Death and SYN floods, which target network layers directly to prevent legitimate connections.
Ping of death
The Ping of Death sends oversized or malformed packets that exceed the maximum IP size limit (65,535 bytes). When these large packets are reassembled by the target server, they overflow the buffer memory, causing the system to crash or freeze, leading to a denial of service.
SYN flood
A SYN flood exploits the TCP handshake process by sending a large number of SYN (synchronisation) requests to a server, but never completing the handshake. The server allocates resources for each connection attempt, which eventually overwhelms its capacity, preventing legitimate users from establishing connections.
Volumetric attacks
Volumetric attacks focus on overwhelming a target’s bandwidth by generating massive amounts of traffic. Attackers use botnets to send huge data volumes to the target, consuming all available network resources. These attacks are measured in bits per second (bps) and can cause widespread network disruption.
UDP flood
In a UDP flood, the attacker sends numerous User Datagram Protocol (UDP) packets to random ports on the target server. This causes the server to repeatedly check for nonexistent applications at those ports, leading to system exhaustion as resources are depleted by this unnecessary processing.
DNS amplification
DNS amplification involves attackers sending small DNS queries to a vulnerable DNS server with a spoofed IP address (the target’s IP). The server responds with large amounts of data directed toward the target, overwhelming its bandwidth. This attack leverages the disparity between the small request size and large response size.
What is the difference between a DoS and DDoS attack?
The primary difference between a DoS (Denial of Service) and a DDoS (Distributed Denial of Service) attack lies in the number of sources involved. A DoS attack originates from a single source, where one device floods the target with traffic to cause disruption.
In contrast, a DDoS attack uses multiple compromised devices, often referred to as a botnet, which work in unison to generate an overwhelming volume of traffic. This distributed nature of DDoS attacks makes them harder to mitigate as traffic comes from various sources, complicating efforts to block malicious activity. Additionally, DDoS attacks tend to be larger in scale and can cause more widespread damage than DoS attacks.
DDoS attack mitigation methods
Mitigating a DDoS attack revolves around three important phases. Detection focuses on alerting the team to these attacks as soon as possible so whenever there’s a spike in suspicious activity, you can respond with equal speed. Regular monthly scanning is also important to ensure there are no vulnerabilities that can be exploited. Response is not only about how your systems respond to an attack but how quick the response is. Finally, routing is all about distributing the fake traffic so your servers don’t get overwhelmed.
Detection
DDoS attacks can happen at the drop of a hat so early detection involves identifying abnormal traffic patterns, such as an unusual spike in requests. Using AI-based anomaly detection systems can help companies distinguish between legitimate and malicious traffic, allowing for quicker response to attacks.
Response
Your AI system has detected an attack. Brilliant, now it’s time to respond. When an attack is detected, initiating a rapid response is crucial. Traffic should be rerouted or filtered using firewall rules and rate-limiting strategies. Specialised anti-DDoS services can be engaged to deflect malicious traffic while allowing legitimate traffic to continue.
Routing
If the goal of a DDoS attack is to overwhelm your server, the best response is to spread out that traffic across multiple servers. Intelligent routing techniques distribute traffic across multiple servers globally, making it harder for attackers to overwhelm a single server. Cloud-based DDoS protection solutions also distribute the load, improving resilience during attacks.
Adaptation
Keeping ahead of DDoS attack patterns is crucial for modelling your security systems. Adaptation involves continually updating defence mechanisms based on the latest attack trends. Integrating AI-driven solutions and real-time monitoring tools ensures that the network remains agile and capable of responding to new DDoS techniques as they evolve.
Safeguard your organisation with Cyber Security Awareness
Cyber security awareness is a vital tool for safeguarding organisations from threats, including DDoS attacks. Regular staff training ensures that employees understand the risks, recognise potential security threats, and follow best practices for protecting company resources. Additionally, having a well-trained response team prepared to act quickly in the event of an attack can minimise damage and downtime.
Cyber security awareness can also offer regular monthly monitoring and simulated attacks to not only help monitor for potential threats but also to see how your systems tackle the real thing. All these features combined mean that cyber security awareness can help foster a culture of cyber vigilance to ensure your business stays protected.
