What is Distributed Denial-of-Service (DDoS) attack?

A Distributed Denial-of-Service (DDoS) attack is a malicious attempt in which the attacker makes it impossible for the services to be delivered. A DoS service makes websites, online services, servers, and other network resources, its target and overfloods them with traffic more than its bearing limit. The intention is, that either the server slows down or even crashes and shut down so that the user’s request cannot be completed.

In DoS, these malicious attacks are sent by one system while in DDoS, many such systems do this work together. DDoS traffic, in simple language, is an unexpected traffic jam on the highway which does not allow regular traffic to its destination. This traffic could be a database being hit with a large number of queries at the same time, packets containing malicious data, a high amount of server requests at the same time, etc.

How does a DDoS attack work?

Internet-connected devices generally perform Distributed Denial-of-Services (DDoS) attacks. The main system which is in direct control of the attacker finds some more vulnerable devices and gains control over them by anyhow hacking them or guessing their passwords, etc. These vulnerable devices which are remotely controlled by the attacker are individually called zombies or bots. Together this whole network is called a botnet. The number of bots in a botnet could be any, ten, hundred, thousand, there is no upper limit for this. 

When the target server or network makes any request, in the botnet, each bot sends a request to the IP address of the target. Which create a lot of traffic and due to this flood of incoming request, the system slows down or crashes and shut down.

What are the reasons attackers use DDosing?

DDoSing is the act of organizations, individuals, and even nation-states launching a DDoS attack for personal gain.

Cyber Vandalism

Vandalism in the digital world is referred to as cyber vandalism. It’s a way for bored youngsters to voice their dissatisfaction with a system or institution. By programming malware to harm digital files, disrupting regular operations, or removing a disc drive, causing the machine to shut down. Its target is both individuals and businesses, even though its objective is financial gain.

Business Competition

The DDoS attack is often utilized as a business strategy. The goal is to disrupt their customers so that they will have a bad experience and switch to a competitor, as well as cause reputational and financial harm. In this scenario, the attackers are experienced, so they spend months attempting to damage competitive internet enterprises.

Hacktivism

When criticizing governments and their policies, the term hacktivism is used. Big business, politicians, and current events are also covered. It will cause a problem for your website if it is against you. They are not technical hackers like other professional hackers; instead, they assault their targets with pre-made tools.

Extortion

Extortion, sometimes known as ransom, is becoming a more common motivator for DDoS attackers. It is done primarily for financial gain, and DDoS attackers will threaten individuals or corporations until the extortion demand is met. They will demand payment in bitcoin, making it difficult for anyone to track them down.

Different types of Distributed Denial-of-Service (DDoS) Attacks

There are mainly three types of DDoS attacks:

1. Volumetric or Network-centric Attacks

This attack uses a huge amount of traffic to flood resources such as the server or website. This attack generally includes ICMU,  UDP, and packet flood attacks. The size of a  volumetric or network-centric attack is measured in bits per second (bps). Domain name system amplification attack is an example of this type of attack which uses the target’s IP address to send the DNS request.

2. Protocol Attack 

This attack sends a very high number of packets to the target network infrastructure. This attack target the transport layer protocol using flaws in those protocols so that the server could get flooded and the request is not completed. It’s one example is the SYN flood attack which sends the target server’s IP address some ïnitial connection requests, which drags out the Transmission Control Protocol which is a never-ending process. The size of the protocol attack is measured in Packets Per Second (PPS).

3. Application layer Attack

In this attack, the application layer gets overwhelmed by several application calls. HTTP (HyperText Transfer Protocol) flood attack is the best example of this attack in which many web pages are refreshed over and over simultaneously. The size of this attack is measured in Request Per Second (RPS). 

How to identify DDoS attacks?

Availability issue is generally the cause behind a Distributed Denial-of-Services (DDoS) attack. So, a DDoS attack can sometimes seem like a non-malicious issue which can cause an availability issue like a down server, many requests from legitimate users, and slow internet.

Some examples which may indicate a DDoS attack are given here. If any one of them or any combination of them is seen, it must be considered:

• If over a short period, one or several specific IP addresses make some consecutive requests again and again.
• If you are attempting a test on a server using a pinging service and it times out.
• If a lot of requests are made from similar devices or similar behavioral characteristics.
• If a server responds with 503 HTTP response because this response shows that either the site is overloaded or down for maintenance.
•  A normal functioning server’s bandwidth always remains even so if you see strong and consistent spikes in bandwidth,  do consider them. 
• If logs show an unusual sequence of traffic spikes at an unusual time.
• If there are unusually large spikes shown by the logs.

How do prevent Distributed Denial-of-Service (DDoS) attacks?

While frankly speaking, there is no ultimate way to prevent the Distributed Denial-of-Services attack, there are a few ways that we can follow to reduce the possibility of being attacked. Those are:

• Get yourself enrolled in a DoS protection service that can detect the abnormal flow of traffic and could redirect that traffic away from you if needed. 
• Create a backup plan for successful communication, mitigation, and recovery in case you are attacked by the DoS attackers.
• Always keep an updated antivirus installed in your system to protect yourself from computer scams.
• You can install Firewall and configure it accordingly so that it can restrict all the traffic coming to you as well as leaving your system.
• Follow good security habits and keep your security up to the required security standards so that access to your account is minimized.

What to do if you experience an attack?

Contact professional for assistance if you feel that you or your organization is experiencing DoS or DDoS attack. Here are a few guidelines to follow:

• First of all, contact your network administrator to know whether the site is actually under maintenance or not. He can monitor network traffic and can tell that is it a DoS attack or not. And use a DoSresource protection service to reroute your traffic. 
• To know the appropriate and exact cause of the site crash or server down, contact your ISP. They will provide you with better guidance to deal with the situation. 
• The attack could be a distraction also so that your other networks can be attacked by more secondary attacks. So do not lose sight of any other host on your network.

Some examples of DDoS attack 

• In 2018, GitHub was targeted by a DDoS attack which is said to be the biggest Denial-of-Services attack to date. GitHub server was attacked by an overflooded server request which caused trouble to millions of people.
• NewZealand’s Exchange was targeted by a volumetric DDoS attack in 2020, due to which it went offline for several days.
• In 2019, a website was attacked in Hong Kong, which was used to organize pro-democracy protests there. It is said that it was China’s Great Cannon DDoS Operation, which caused huge congestion on the site.
• In 2020, several organizations were threatened by a DDoS attack. It was threat actor groups Fancy Bear and Armada Collective, who threatened them and asked to pay a bitcoin ransom.

Conclusion

DDoS i.e. Distributed Denial-of-Services attack is a malicious attack that can have a severe impact on a targeted business or organization. But as there is no solid way to prevent this attack, we need to take precautions to save ourselves from this attack. If we will be more careful while being online, we can surely prevent this attack.