DENIAL OF SERVICE (DoS) ATTACK – Part 1

7 Comments / Cybersecurity, Security

What is DoS?

Denial of service occurs even outside of the digital world. As the name implies, it occurs when access to a service of interest is denied when requested by a client. Under the major goals of security, denial of service falls under the Availability category. Denial of service affects not only services but could affect data also. For example, a ransomware encrypts victim’s data, and then a ransom is requested by the attacker(s) to decrypt or restore the data. Though this is classed as a ransomware attack, it is also a denial of service attack because data required for normal or proper business functioning was made unavailable or unusable at the point when it was needed or queried.

A Denial of service attack could be deliberate and could also be a result of other factors like carelessness of personnel, unforeseen natural disasters etc. However, more often than not, DoS occurs as a result of attacks targeted towards a particular service at a particular Organisation, country or even individual systems. Traditional DoS attacks are performed by sending more requests than a target can handle. E.g. For a web server, excessive GET requests could be sent so that the server is overwhelmed with requests and cannot keep up with serving all the client requests. At this point, the server is not able to respond to any requests including legitimate client requests because it has been hit with too much for it to handle.

In some types of DoS attacks, multiple machines could be infected to form a combined force to launch a more powerful DoS attack against a target. This is called a distributed denial of service attack (DDoS) as seen above. These infected systems form what is called a Botnet. It is possible for users of the machine not to know that their PC has been infected and that they are now part of a Botnet (like in the case of the Simda bot). When “Denial of Service” is mentioned, many think of just some nerd or group of nerds or hackers sending some commands or lines of code to initiate the denial of service against the target. Though this might be true sometimes, launching a DoS attack is as easy as clicking a button after entering the target IP Address. Also, a DoS attack does not necessarily need to be sophisticated or performed using a computer. For example, let’s say we have a running database server secured with passwords, multi-factor authentication, a firewall and even Intrusion detection and prevention (IDPS) systems but with poor physical security e.g. bad or cheap locks that could be easily picked or bypassed, a member of staff could access the server room and pull out the power cable thereby causing the server to lose power and goes off. This is a no brainer, the server definitely would go off and every client who tries to query this server for data would get no results. This kind of attack could be unintentional like in the case of a cleaner or intern who is not aware of the significance of being careful around such delicate or sensitive piece of hardware and this could also be intentional like in the case of a disgruntled employee or an insider threat working for a competitor. To be continued in Part Two.  

7 thoughts on “DENIAL OF SERVICE (DoS) ATTACK – Part 1”

  1. Samuel A.

    Glad to come across this article well simplified indeed, makes the topic more understandable and interesting. Good job!. Thank you.

    Reply
  2. Joe

    This is actually interesting to read, and easy to understand. I like the way you guys are able to explain tech subjects in a way non-tech people would understand. Keep it up>!^

    Reply
  3. Favour O.

    The examples used to explain here are actually realistic and have made me realize there is a need to organize training and awareness even for cleaners at my place of work :). An eye opener.

    Reply

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