What is a DoS Attack?
A denial-of-service attack, also called a DoS attack, is a means of overburdening a network’s bandwidth or computer system to the point that it can no longer function. Attackers create DoS attacks by directing too much traffic to the targeted server or website, causing it to fail and thus preventing it from offering normal services to its legitimate users. Based on the target network, various services could be affected, such as email, websites, online accounts (i.e. banking), or other types of services.
On the other hand, a distributed denial-of-service (DDoS) attack occurs when attackers flood a network server with traffic from many distributed sources. It means that just blocking the source of traffic won’t be enough to prevent DDoS attacks. There are also different types of DDoS attacks which might require different methods of security measures such as smurf attack, SYN flood, and Layer 7 DDos attacks (also known as application layer attacks).
Despite the fact that DoS attacks may not usually lead to data theft or destruction, they can have a substantial financial impact on the targeted companies. Recovering after a DoS attack takes time and money, not to mention the extra costs of lost revenue, damaged reputation, and unhappy customers.
How Do DoS Attacks Work?
As opposed to malware or viruses, DoS attacks do not require any special program to perform malicious functions and tend to target web servers of high-profile organizations. Rather, they exploit security vulnerabilities inherent in the way computer networks exchange information. Suppose, for example, you visit an online store to buy products. Upon visiting the website, your machine sends a small packet of information to the network interface of the target website. The information packet serves as a greeting message saying, “Hello, I would like to visit you, please let me in.” Your message is delivered to the website server, and it responds by asking, “Ok, are you real?” In response, your machine says “Yes,” and the connection to the website is established.
During DoS attacks, the perpetrator rigs their PC with a bot that says “Hello” hundreds or thousands of times within a few seconds. Since the website server on the other end doesn’t know whether these initial messages are genuine, it responds in a normal way, waiting for a minute for its are-you-real response to get the necessary reply. The response queue quickly fills up with unresolved false data requests. As the attacking bot continues to send requests that exceed server capacity, the website server can no longer respond to any messages. Consumers are blocked from accessing the enterprise’s services and information, and the victimized business’s computer systems are paralyzed.
How to Prevent DoS Attacks
The U.S Department of Homeland Security’s Cybersecurity and Infrastructure Security Agency (CISA) is the national coordinator for critical infrastructure security and resilience. They monitor the entire threat picture and collaborate with government agencies and industry to defend against known threats while securing the nation’s critical network infrastructure against future threats.
CISA states that DoS attack warning signs appear to external users like non-malicious availability issues (service disruptions) such as routine systems maintenance or common technical difficulties relating to a particular network. A DoS attack can result in unusually slow network performance, or it can render a website or other target server completely inaccessible.
While external users may not be able to distinguish between a DoS attack and other technical problems with a particular website, the internal network administrators and security teams can easily identify a malicious attack. Simply identifying an attack is not helpful, however, unless you can stop it and restore your systems to normal operations. Consider the four defensive methods listed below.
1. Monitor Traffic
Organizations can employ a service that identifies or redirects unusual traffic movements associated with denial-of-service attacks. Meanwhile, normal traffic is allowed to pass through.
2. Strengthen Your Security Posture
Among the measures you can take are:
- Strengthening your internet-connected devices to avoid compromise.
- Configuring firewalls exclusively to prevent DoS attacks.
- Keeping your anti-virus software up-to-date
- Consider using a content delivery network (CDN) to handle the load in case of an attack
- Track and manage unwanted traffic using all available security practices.
3. Develop a DoS Attack Response Plan
In the event you suffer a DoS attack, a disaster recovery plan that includes communication, mitigation, and recovery is crucial to responding quickly and effectively. Your DoS & DDoS response plan should clearly document how to maintain business operations in such scenario.
4. Analyze Network Traffic
With the help of an intrusion detection system or firewall, network traffic can be easily viewed. The system administrator can create rules that issue alerts for unauthorized or fake traffic, detect abnormal traffic flows and sources, and filter out network packets that match certain criteria.
Final Thoughts
Denial-of-service attacks continue to increase. They are the digital equivalent of malicious sabotage. The saboteurs reap no direct benefit other than slowing or shutting down a company’s e-commerce operations or other communications. A DoS attack on a company’s email servers can cripple their ability to communicate with customers, suppliers, and partners. An attack can cause more than just short-term server downtime; it can cause financial losses, brand damage, and dissatisfied customers.
Any company with an internet presence and/or an email system could become a target. The smaller the company, the more devastating a DoS attack can be. Therefore, every organization must be prepared to defend against a DoS attack.
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