How to Prevent DOS Attacks?

The denial-of-service (DoS) raid is a tried-and-true cyber-criminal procedure. The initial documented case dates back to early 2000 when a 15-year-old Canadian cyberpunk took down some major e-commerce sites, including Amazon and eBay.

Fast-forward two decades and a DoS attack can however be dangerously active. These attacks have evolved bigger and bolder. But with the proper DoS attack prevention tricks, organizations can hinder or mitigate the turmoil they can cause.

Although denial-of-service attacks have lived around since the nineties, they have never been further relevant. There were 9.5 million denial-of-service raids in 2019. The amount has been projected to attain 15.4 million by 2023. This unexpected evolution makes it necessary for every safety professional to be proficient in denial-of-service attack prevention.

After browsing the definition and studying the history of this cyberattack, this article summarizes the recent best practices for compensating for this threat. 

What is a denial of service attack?

A Denial-of-Service (DoS) invasion is a raid meant to close down a device or web. This makes it unavailable to its intended users. DoS sabotages are performed by flooding the prey with traffic or sending it data that triggers a crash. In both examples, the DoS outbreak robs legitimate users (i.e. employees, members, or account holders) of the employment or resource they wanted.

Preys of DoS raids often target web servers of high-profile companies such as banking, commerce, and media corporations, or union and trade groups. Though DoS attacks do not generally result in the robbery or damage of important data or other assets, they can cost the target a huge deal of time and capital to handle.

There are two common techniques of DoS attacks:

  • Flooding assistance 
  • Crashing services

Flood outbreaks occur when the network receives too much traffic for the server to buffer, resulting in them slowing down and ultimately stopping. 

Popular flood attacks include:

Buffer overflow attacks  

The most prominent DoS attack. The idea is to transmit more traffic to the web address that the programmers have created for that network to deal with. In addition to others that are developed to exploit bugs specific to certain applications or systems.

ICMP flood

Influences misconfigured network devices by transmitting spoofed packets that ping every computer on the targeted web, instead of just one particular appliance. The system is then activated to enhance the traffic. This attack is similarly known as the smurf attack or ping of death.

Other DoS attacks completely exploit exposures that cause the victim’s system or assistance to crash. In these raids, input is sent that takes advantage of bugs in the mark. That thereafter crashes or harshly destabilizes the system so that it can’t be accessed or utilized.

A different type of DoS invasion is the Distributed Denial of Service (DDoS) attack. A DDoS attack happens when numerous systems organize a synchronized DoS attack on a single victim. The fundamental difference is that instead of being sabotaged from one area, the target is sabotaged from many locales at once. The distribution of hosts that interprets a DDoS provides the attacker numerous advantages:

  • He can influence an incredible amount of devices to perform an extremely disruptive attack
  • The area of the attack is impossible to recognize due to the spontaneous distribution of attacking strategies (often worldwide)
  • It is more problematic to shut down numerous machines than one
  • The true damaging party is very tough to recognize, as they are concealed behind many (mostly compromised) networks
  • Recent security technologies have evolved devices to protect against most forms of DoS attacks. But due to the unusual characteristics of DDoS, it is still considered a lofty threat and is of bigger concern to companies that fear being targeted by such a raid.

 How does it work?

As we recently talked about, DoS and DDoS attacks have the main motive of making a service inaccessible. To accomplish this objective, attackers generally consider one of two particular goals: exhaust the targeted server resources compelling it to proceed with, or overfilling the communication channel to disconnect the server.

Algorithmically, attackers use protocols and service features to achieve their goals. Some of the extensively known procedures are SYN flood, TTL expiry raids, amplification attacks, and low-rate targeted raids. We’ll briefly talk about each of them in the following subsections.

SYN Flood

The SYN flood invasion (sometimes called a half-open attack) manipulates the connection management technique of the TCP protocol.

The central idea of this procedure is to deliver a lot of synchronization requests to a TCP server without transmitting any posterior acknowledgment information to establish connections.

In such a manner, the TCP server still pauses for the acknowledgment statement from the fraud users for a substantial duration until declining the connection due to timeout.

Nonetheless, the huge amount of fake requests consumes the server’s resources. So, the overcrowded server dismisses the connection’s recent requests, including requests from legit users.

TTL Expiry Attack

The victim of TTL expiry raids is the routers in the hub network. The main indication is to massively send packets that will discontinue the TTL counter at some certain router.

Since the TTL terminates, the router will assign additional computational resources to develop and send an “ICMP time exceeds” response.

Since there are tons of packets terminating the TTL at the exact router, it becomes overcrowded and ends or relatively slows down operating into a bottleneck in the web.

Amplification raids consist of mocking requests with the target server IP and thus transmitting them to services that produce huge amounts of traffic as feedback.

Illustrations of services that can be manipulated to enhance attacks are based on DNS and NTP.

In the DNS scheme, the attacker manipulates the acknowledgments of the DNS lookup systems to create malicious traffic.

In the NTP case, attackers usually manipulate the system called moonlit, which transmits data about hundred hosts that have newly requested the NTP server. Thus, a simple and minor request affects a huge amount of data being transmitted.

 Low-rate Targeted Attacks

Unlike the other attack procedures in this tutorial, which are generic invasions, low-rate targeted attacks influence the unique characteristics of very specific services.

Low-rate invasions do not have the objective of flooding the targets with web traffic. The main idea is to provide the least traffic but results in the utmost influence on the service.

For instance, let’s consider a networked AV service. The attackers can develop network packets with many labels and structures checked by the AV. So, the forged packets expect much more computational resources to be processed by the AV than the average in natural conditions.

Since different AVs may have varied behaviors, the attacker will require to make a different analysis and possibly forge another attacking packet to influence heterogeneous AV servers.

The main advantage to the attacker is that it is simpler to mimic legit users’ aspects in low-rate attacks. So, it is harder for security systems to distinguish and block malicious sources.

How to prevent dos attacks?

As the Cybersecurity and Infrastructure Security Agency (CISA), run by the U.S. Department of Homeland Security, remarks, “the signs of a DoS invasion can approximate non-malicious availability issues, such as technical issues with a specific system or a network administrator accomplishing maintenance.”

Additionally, CISA adds, “unusually sluggish web performance and unavailability of a specific website can be powerful signs of a DoS attack.”

For denial of service prevention and protection, the companies can take the following actions against the attacks:

  • Survey and investigate network traffic: Network traffic can be regulated via a firewall or intrusion detection network. To prevent denial of service attacks, the supervisor can set up restrictions that generate alerts for uncommon traffic. Also, to identify traffic sources, or decline network packets that fulfill specific criteria.
  • Enhance their safety posture: This encompasses enhancing all internet-facing gadgets to prevent compromise, establishing and maintaining antivirus software, establishing firewalls configured to maintain against DoS attacks, and developing robust security strategies to monitor and manage undesirable traffic.
  • Control traffic: Companies can enroll in a service that inspects or diverts unusual traffic flows. It is generally related to a DoS attack and enables regular traffic to proceed on the network.
  • Establish a DoS attack response plan: To prevent denial of service attack the key is to create and practice a disaster recovery plan. And ensuring that it covers communication, mitigation, and recovery.

Types of dos attack

There are three major categories of DoS attacks:

1. Application-layer Flood

In this attack type, an attacker just floods the service with requests from a spoofed IP address in an attempt to hinder or break the service, illustrated in. This could take the structure of millions of requests per minute or a few thousand requests. 

The requests are particularly sent to targeted resource-intensive services that gobble resources until the service is incapable of continuing processing the requests.

An attacker floods the service from a sole IP address. Preventing application-layer DoS raids can be complicated. The best strategy to help mitigate these kinds of invasions is to outsource pattern detection and IP filtering to a third party.

2. Distributed Denial of Service Attacks (DDoS)

Distributed Denial of Service (DDoS) attacks arise similarly to DoS attacks except that requests are carried from numerous clients as obstructed to just one, illustrated in.

 DDoS attacks often implicate many “zombie” devices (devices that have been formerly compromised and are being regulated by attackers). These “zombie” machines then transmit massive numbers of requests to a service to destroy it.

DDoS attacks are famously tough to mitigate, which is why outsourcing web filtering to a third party is the instructed approach. 

3. Unintended Denial of Service Attacks

Not all DoS invasions are popular. The third attack category is the “unintended” Denial of Service attack. The ecclesiastical illustration of an unintentional DDoS is called “The Slashdot Effect (opens unusual window)”. 

Slashdot is an internet communication site where anyone can publish information stories and link to other sites. If a correlated story comes to be popular, it can result in millions of users exploring the site overfilling the site with requests. 

If the site isn’t built to deal with that type of load, the high traffic can slow or even crash the correlated site. Reddit and “The Reddit Hug of Death (unlocks new window)” is other excellent illustration of unintentional DoS.

An attacker uses zombie appliances to start a DDoS against the target.


What is DDOS Attack?

DDoS (Distributed Denial of Service) is a type of violent cyber-attacks in which hackers or cybercriminals operate online services, system resources, or host devices inaccessible to their intended users on the Internet.

Can a firewall prevent dos attacks?

Firewalls can’t safeguard against complicated DDoS attacks; entirely, they behave as DDoS passage points. Attacks pass right through available firewall ports that are intended to allow entry for legitimate users

Ares dos attack permanently on Service is somewhat easy to acquire by cybercriminals as data is promptly damaged by causing harm to the hardware. 

Permanent Denial of Service is an extremely difficult type of cyber attack as the harm to the hardware is so difficult that it results in loss of data and also hampers the hardware device permanently.

How common are DDoS-attack?

This was the extensively popular type of invasion in the earlier days of the Internet, where services were fairly small in scale and security technology in its beginning. Still, currently, an easy DoS attack is always easy to avoid as the attacker is easy to recognize and block.

Final words

As is often the case, practice and planning are significant to denial-of-service attack prevention. Analyzing your system for exposures is time-consuming, as is drafting a DoS comeback plan. 

Therefore ensuring your safety staff can differentiate the timely warning signs of a raid in progress. Each pillar of prevention is a challenge in its own right, but the product is the stability of the mind.

One of the greatly beneficial ways of safeguarding your system against DoS attacks is to lessen the attack surface via micro-segmentation. 

At Boys, we use endpoint micro-segmentation to reduce web exposure to its most justifiable factor and optimize its stability to attack.