Ever tried visiting a website that just refused to load? Or Imagine you’re ready to make that all-important online purchase from your favorite bustling online marketplace but suddenly find it has grounded to a halt. It might have felt like the Internet itself was taking a nap, leaving you staring at that spinning wheel in frustration. In many instances, it could be some technical issue with the website’s server or network, or an issue with your Internet Service Provider.
In any case, there probably was a perfectly acceptable explanation for the disruption. However, what if it wasn’t a technical glitch? What if it was a deliberate attack? An attack that prevents the intended consumers of digital services from accessing them. This is the chilling reality of a Denial-of-Service (DoS) attack, a malevolent assault used by cybercriminals designed to cripple websites, servers, and networks, leaving legitimate users locked out and frustrated.
If that isn’t bad enough, a denial of service assault does far more harm than just inconvenience and annoyance. DoS attacks can cause financial losses, harm a company’s reputation, and even jeopardize vital services. There have even been reports of certain businesses using such attacks to harm competitors. Subsequently, they can cost businesses millions of dollars in losses, disrupt essential services, and even threaten democracy.
So fasten your seatbelts because we’re about to go into the mysterious realm of denial-of-service (DoS) assaults, exploring what they are, their mechanisms, how they work, and what we can do to prepare ourselves against an attack.
Let’s start by defining the term “denial of service.” A denial of service (DoS) is an intentional or inadvertent breach of a computer system’s availability that can impact any of the various components of a computer system, including the hardware, software, and data of the computer itself. It can also affect the peripherals of a computer system and the network infrastructure that allows computers and peripherals to communicate with each other. Therefore, a denial of service is essentially a prevention of the availability of resources from a computer or website.
A Denial of Service attack, however, is an intentional attack on a computer system’s availability of resources. It is essentially where a resource of a system is depleted by an attacker constantly trying to access it, thereby preventing legitimate users from accessing that resource. The resource can be memory, processing power or network bandwidth, and the attack can have a specific target.
Another form of service denial is the disruption of an entire network, either by disabling the network or by overloading it with junk traffic. A noted example of a DoS is an email attack. This involves disrupting or disabling an email service, preventing users from sending or receiving messages. The objective is to overwhelm the email server or network infrastructure, rendering the email service temporarily or permanently unavailable to users.
Denial of Service (DDoS) Attack Types
Let’s briefly run through some of the types of DoS attacks, each one has its own set of techniques and harmful effects. The following is a list of some of the more frequent types.
1. UDP Floods
A large amount of UDP (UDP is a protocol to send packets across the Internet) messages are routed to arbitrary ports in large quantities. An attacker’s objective in a UDP flood attack is to overwhelm a target’s network bandwidth and resources by sending a high number of UDP packets to that point.
2. ICMP Floods
ICMP is a protocol that sends error messages across the Internet. An attacker can flood a network with ICMP messages. Some ICMP attacks are the Ping of Death and Smurf attacks.
3. HTTP Floods
This is a type of distributed denial-of-service (DDoS) assault that aims to overload a targeted server with HTTP requests. This is similar to ICMP and UDP. I’ll discuss DDoS later.
4. SYN Floods
A SYN Flood is where the attacker quickly establishes a connection with a server without completing it, filling up server resources with half-opened TCP connections.
5. Ping of Death
Sending oversized ping packets to crash devices.
6. Teardrop Attack
Fragmented packets designed to confuse and crash systems.
7. Slow Post Attacks
Sending incomplete HTTP requests that tie up server resources.
8. SQL Injection Attacks
Injecting malicious code into database queries to overload the system.
9. DDoS Attacks Against Specified Functionalities
Targeting vulnerabilities in login systems, shopping carts, etc.
10. Multi-Vector Attacks
Combining volumetric, protocol, and application layer attacks for a complex assault.
11. Low-Bandwidth DoS Attacks
Using minimal traffic but exploiting specific vulnerabilities for significant impact.
Distributed Denial of Service (DDoS) Attack
In a DoS attack, one attacker is able to launch an attack on the victim from one computer. However, a distributed denial of service (DDoS) attack is one that occurs when the attacker is able to launch an attack simultaneously from as many compromised computer systems as possible.
The effects of the attack are therefore multiplied. DDoS attacks present a significant danger to companies and organizations, and it appears that the threat is growing. One study found that over a few weeks, more than 13000 attacks took place over 6000 distinct targets. Popular services like Amazon and Hotmail were affected. These attacks make the victim’s computer system inaccessible by flooding their servers, networks, and end-user systems with useless traffic so that legitimate users cannot access their resources.
Therefore, a DDoS attack is a coordinated attack launched from as many computers that have been compromised as possible. It could be one attacker at each compromised machine, who employs mechanisms to synchronize the attack with other attackers. With today’s DDoS tools, only one attacker is enough to control the attack through one compromised computer.
This is what happened in September 2017 when it is believed one person conducted the largest-ever DDoS attack against Google. The assault, which was 2.54 terabits per second in scale, was directed at Google services. To get an idea of this, it means 2.54 trillion bits of malicious traffic were being sent to Google’s servers every second, bombarding 180,000 web servers with bogus packets. In the six months leading up to this assault, the same attacker or perhaps attackers launched repeated distributed denial of service (DDoS) operations against Google’s infrastructure.
Direct DDoS and Reflector DDoS
Alright, let’s delve a little deeper into DDoS. DDoS attacks fall into one of two categories: reflector and direct. In a direct DDoS attack, the attacker can install zombies or malware on several websites dispersed throughout a network using master and slave zombie machines that themselves have become infected with malicious code. The master zombies are triggered and coordinated by the attacker, who also sets off the slave zombies.
With a reflector DDoS, an additional layer of computers is added. The target’s IP (Internet Protocol) address is included in the packet’s IP header as the source IP address by the slave zombie in this kind of attack. The reflectors, which are the uninfected computers, are the recipients of these packets. Response packets aimed at the target machine come from the uninfected machines.
For this reason, an assault using a reflector DDoS is more destructive than a direct DDoS because it may quickly involve more devices and traffic. In addition, the fact that the assault originates from widely distributed unaffected workstations makes it more challenging to track down the attack or filter out the attack packets.
A famous DDoS attack that employed this technique was also one of the largest DDoS attacks on record and occurred in February 2018. The attack targeted GitHub, a widely used platform for software development and version control. The attack sent 1.35 terabits per second to the servers of GitHub, this was, at the time, one of the biggest distributed denial of service assaults. The attack used reflections and amplification (amplification generates a much larger response that is sent back to the target’s IP address. The amplification factor is significant, meaning the response can be many times larger than the original request.) During the attack, GitHub experienced intermittent outages over a period of 10 minutes.
Counteracting and Responding to a DoS and DDoS Attack
So I’ve gone on for a while talking about the various kinds of denial of service attacks, so let’s talk about how to prevent one. Well, to be honest, it’s not quite possible to completely prevent a denial of service attack. With this in mind, it is important to consider that prevention is better than cure. For further information, you can take a look at NETSCOUT’S DDoS Threat Analysis Report or CloudFlare’s DDoS Trends and Analysis Report which offers comprehensive insights into global DDoS trends, including attack vectors, frequency, and targeted industries.
There are numerous countermeasures for DoS attacks, these strategies and tools can be implemented to significantly reduce the risk and impact of these attacks. I’ve broken them down into three parts.
Prior to the Attack
These are measures that allow a company or organization to be better able to withstand the attack without preventing legitimate customers from accessing their services. These techniques include enforcing policies about resource usage, and to make backup resources accessible on demand. Additionally, preventative methods alter the protocols and systems that are used on the network in order to lessen the likelihood of attacks occurring. Here are a few measures you can take before any attack.
1. Strengthen Network Security Measures
Implement firewalls to filter incoming traffic, thereby preventing malicious requests and minimizing the attack surface. Install intrusion detection devices that are equipped with intrusion prevention systems (IPS) in order to identify and prevent malicious traffic in real time. Ensure patches are installed and kept up to date to guard against TCP SYN flooding.
2. Reduce Your Area of Attack
Disable any network services that are not being utilized or are not required. It is important to disable unneeded ports, protocols, and programs in order to reduce the number of potential entry points that attackers may exploit.
3. Implement Network Segmentation
In the event that an attack does take place, you should divide your network into smaller portions to minimize its spread.
4. Set Limiting and Throttling
Set limits on the number of requests a user or IP address can send to your server within a specific timeframe. This helps limit the impact of an attack.
5. Load Balancing
Distribute incoming traffic across multiple servers using load balancers, helping to prevent a single point of failure.
6. Redundancy
Invest in redundant and fault-tolerant network configurations.
7. Backups
Have regular backups, especially of important information.
8. Use a DDoS Mitigation Service
Utilize the services of expert organizations that offer dedicated DDoS mitigation services. These services have the capability to detect and eliminate harmful network activity during a cyber assault, hence enabling the passage of genuine network traffic. They are sometimes called always-on DDoS mitigation.
9. Cloud-Based Services
Consider using a cloud-based service like CloudFlare or AWS that have the capability to absorb and mitigate DDoS assaults. Many cloud-based services provide DDoS security as part of their services.
10. Incidence Response Plan
Develop and implement an incident response plan specifically designed for mitigating DDoS attacks. The strategy must encompass communication methods, strategies to be implemented during an attack, and procedures for interacting with law enforcement, if required.
During the Attack
These measures aim to identify the attack at its inception and to react immediately to mitigate the effects of the attack on the target. Detection entails the process of actively searching for suspicious patterns of behavior. The response involves filtering packets that are likely to be associated with the attack. Here are a few measures you can take during an attack.
1. Monitor Network Traffic
Conduct routine analysis of traffic patterns to detect any abnormal activity that might potentially signal that an attack is occurring.
2. Perform Performance Checks
Observe your system performance and establish baselines for ordinary activity, any deviation from the norm should be investigated immediately.
3. Implement Incidence Response Plan
By implementing the response plan, you’ll know what steps to take if you’re under attack. Including who to contact to mitigate the situation.
During and After the Attack
At this stage, you’re trying to ascertain the origin of the attack as a first measure in averting subsequent attacks. Nevertheless, this approach usually fails to provide prompt or effective outcomes in order to counteract a continuing assault. Here are a few measures to take after an attack.
1. Communication
Ensure all stakeholders, including consumers, are aware of the issue. Provide updates on the progress that has been made in mitigating the attack and any impact that it may have had on services.
2. Law Enforcement Engagement (If Applicable)
Consider contacting law enforcement if the attack is very severe or if it includes criminal activities. It is advisable to provide law enforcement with any relevant information and cooperate with their investigation.
3. Analyze Attack Patterns
It is important to carry out a thorough analysis of the attack patterns. Get an understanding of the features of the attack, including the volume, duration, and tactics that were utilized. This information can be valuable for future prevention.
4. Review Logs and Incident Data
Analyze logs and incident data to gain insights into the attack. Investigate the manner in which the attack took place, identify the systems that were impacted, and determine whether any vulnerabilities were exploited.
5. Implement Additional Security Measures
Strengthen your overall security and deploy additional security measures based on the lessons that you have learned from the cyberattack. This may include adjusting the firewall, upgrading the intrusion detection and prevention systems, or patching any vulnerabilities.
6. Review and Update DDoS Mitigation Strategy
Assess the effectiveness of your current DDoS mitigation strategy and make any necessary updates. Consider adding more redundancy, and capacity, or diversifying mitigation techniques.
Summary
With everything connected these days, the Denial of Service attack is a dangerous foe that may damage the foundation of our online lives. Maintaining awareness and putting strong security measures in place are essential to shielding systems against DoS attacks.
Any countermeasure’s efficacy varies depending on the particular kind of DoS assault, therefore several tactics may need to be combined into a layered strategy essential for complete security. To remain ahead of emerging threats, test and upgrade your defenses often. The possibility of DoS attacks is a constant concern for enterprises, organizations, and individuals alike navigating the ever-expanding digital frontier. Therefore, we must be proactive in strengthening our digital defenses and remain watchful.
As I end, it should be noted that although it may not be possible to completely prevent a denial-of-service attack, the cybersecurity strategies discussed in this article can greatly improve and reduce the impact of potential attacks. By implementing these measures and developing a holistic security strategy, organizations can enhance their defense against denial-of-service attacks and mitigate the impact on their systems and services.
