5 Jul 2023

Denial of Service (DoS)

Denial of Service
A Denial of Service (DoS) is a type of cyber threat that makes a website, application or other service unusable to it's intended users. 

A DoS attack is usually done by launching so many attempts to use the service that the server on which the service is based becomes overloaded and unable to deal with the access attempts, or the attacker sending information that triggers a crash.

After launching the attack, the cyber criminal can ask for a fee to be paid to restore access to the service, or simply sit back and enjoy the chaos they have caused.

DoS attacks can cause a lot of harm to your company. This includes:

  • Making your website or application inaccessible to customers.
  • Taking down your internal network.
  • Wasting time and resources.
  • Damaging the company reputation.
  • Costing a lot of money to resolve.

A DoS attack can harm your company's reputation by:

  • Making your website or app inaccessible
  • Making you unable to help customers due to the internal company network being down

Denial of Service involves the use of a huge number of network of devices, called a botnet, to carry out a large-scale DoS attack against a single target. These attacks using many devices are incredibly difficult to stop. The botnet overload target site or application with connection attempts.

To grow the botnets used for these attacks, cyber criminals spread malware over email and the internet. Infected devices are then used for distributed attacks - often without the owner realising that anything suspicious is taking place.

The best thing you can do to stop DDoS attacks from taking place is to ensure that your own devices won't become unwitting players in these botnets. While there is no way to completely avoid becoming a target of a DoS or DDoS attack, there are proactive steps administrators or users can take to reduce the effects of an attack on their network.

How to stay safe:

  • Update your Operating System (OS) with latest security patches.
  • Run regular anti-malware scans
  • Avoid browsing illegal or suspicious sites
  • Watch out for phishing emails. Don't click on links or open attachments in unexpected emails.
  • Enrol in a DoS protection service that detects abnormal traffic flows and redirects traffic away from your network. The DoS traffic is filtered out, and clean traffic is passed on to your network.
  • Use Intrusion Detection and Prevention Systems (IDS/IPS) to detect and block DoS attacks by analysing network traffic and blocking malicious traffic.


Image credit: noulakaz.net