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Zero-day Attacks Explained: What they are, how they occur, and how you can protect yourself against them?

May 23, 2023

In the ever-evolving world of cybersecurity, zero-day attacks have emerged as the ultimate clandestine weapon. Operating in the realm of unknown vulnerabilities, these stealthy exploits pose a grave risk to organisations and individuals alike.

This article unveils the menacing world of zero-day attacks, shedding light on their nature, implications, and the urgent need for proactive defences in an increasingly vulnerable digital age.


What are Zero-Day Attacks?


Zero-day attacks, also known as zero-day exploits or zero-day vulnerabilities, refer to cyberattacks that target software vulnerabilities unknown to software vendors and security experts. The term “zero-day” signifies the lack of any prior knowledge or time to prepare defences against these attacks. This makes zero-day attacks particularly dangerous and challenging to detect and prevent.

Unlike other types of attacks that exploit known vulnerabilities, zero-day attacks take advantage of undisclosed flaws in software or operating systems. These vulnerabilities are often discovered by malicious actors who keep them secret or “in the wild,” allowing them to exploit these weaknesses undetected. By exploiting zero-day vulnerabilities, attackers can gain unauthorised access, control systems, steal sensitive data, or execute malicious code.

It’s important to distinguish between three different terms that you might come across when reading about zero-day attacks:

  • Zero-day Vulnerabilities – Undisclosed or unknown flaws or weaknesses in software, operating systems, or applications.
  • Zero-day Exploits – Actual attacks or methods used to take advantage of zero-day vulnerabilities.
  • Zero-day Attacks – The overall concept encompassing the use of zero-day exploits to carry out cyberattacks.



How and Why do Zero-Day Attacks Occur?


Zero-day vulnerabilities are typically uncovered by skilled hackers, security researchers, and intelligence agencies. These individuals and organisations invest significant time and expertise in identifying and exploiting software weaknesses. They employ techniques such as code analysis, reverse engineering, or using specialised tools to discover these vulnerabilities. Once a vulnerability is found, it is often kept confidential, providing an advantage for future exploitation.

In many cases, attackers are motivated by financial gain. They may use zero-day exploits to steal sensitive data, conduct ransomware attacks, or sell the discovered vulnerabilities to the highest bidder on underground markets. State-sponsored organisations engage in zero-day attacks for strategic advantage, espionage, or disruption of critical infrastructure. Cybercriminals, hacktivist groups, and advanced persistent threat (APT) actors also employ zero-day attacks to further their malicious agendas.

Zero-day attacks can be targeted at just about anyone or anything, including small businesses, public organisations, and multinational corporations. If your business is in possession of valuable confidential data or if accessing your business’s private network could result in financial gain for an attacker, it’s important to protect yourself from zero-day attacks.


Examples of Zero-day Attacks


It’s not hard to find examples of zero-day attacks that have affected businesses around the world.


Sony Pictures Entertainment

In 2014, Sony Pictures Entertainment fell victim to a significant zero-day attack that had far-reaching consequences. The attack, allegedly carried out by a group known as the “Guardians of Peace,” exploited undisclosed vulnerabilities in Sony’s computer systems and resulted in the massive theft and public release of sensitive data, including confidential employee information, internal communications, and unreleased movies. The breach caused significant disruption to Sony’s operations, tarnished its reputation, and led to financial losses.



Microsoft has also fallen victim to a zero-day attack. In April 2017, the company was alerted to a zero-day attack that had targeted its Microsoft Word software. The attackers employed a type of malware to exploit a vulnerability present in an unpatched version of Word and inserted malicious code into the software. Antivirus software vendor McAfee identified the attack and notified Microsoft, but by this point, millions of users had already fallen victim to the attack.


How to Protect Yourself Against Zero-day Attacks


If you want to keep your business safe from zero-day attacks, there are some simple steps that you can take to safeguard your company:

  • Keep Your Software Up to Date – Promptly install software updates and security patches to ensure you have the latest protections against known vulnerabilities.
  • Employ Robust Security Software – Use reputable antivirus and anti-malware software to detect and block potential zero-day threats.
  • Enable Automatic Updates – Configure your devices and software to automatically install updates, reducing the risk of exposure to known vulnerabilities.
  • Practise Safe Browsing – Be cautious when clicking on links, downloading files, or opening email attachments from unknown or suspicious sources.
  • Use a Firewall – Activate and configure a firewall to create a barrier between your network and potential threats, providing an additional layer of defence.
  • Be Vigilant with Email – Exercise caution with email attachments, even from seemingly legitimate sources. Avoid opening suspicious emails or clicking on links within them.
  • Implement Intrusion Detection Systems – Employ security tools that monitor network traffic for unusual or suspicious activities, helping to detect zero-day attacks in real-time.
  • Backup Your Data – Maintain up-to-date backups of your important files and data to mitigate the potential impact of a successful zero-day attack.
  • Enlist an Expert – It’s prudent to let experts take care of cybersecurity in your business. They are experienced and skilled in putting measures in place to prevent data breaches.





The threat of zero-day attacks should never be underestimated. By staying informed, implementing robust security measures, and fostering a culture of cybersecurity awareness, individuals and organisations can fortify themselves against the stealthy threat posed by these elusive vulnerabilities.


Why Choose Eventura as your Cybersecurity Partner?


With over 20 years experience in cybersecurity, we know our stuff. Our team of cybersecurity experts can complete a full audit of your business and identify any areas of weakness, which could leave you vulnerable to cyberattacks.

We were even mentioned in the Governments National Cyber Security Centre (NCSC) Annual Review 2020 when we were chosen to test their “Exercise in a Box” designed to help small businesses prepare and respond to cyberthreats. You can read the article here.

There is a common misconception that cyberattacks don’t happen to SMEs but this couldn’t be further from the truth. With our expert knowledge, we can help you protect your business’s future from the ever increasing threat of cybercriminals.

If you would like to speak to one of our cybersecurity experts or request a cybersecurity audit, you can request a free call back here.

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