A Zero Day Attack in Cyber Security | 0day | Defined in Detail

Last updated on May 25th, 2023 at 12:43 pm

 What is a Zero-Day (0day) Attack | The Zero-day Exploit

    Every computer program either computer application, mobile application, or website every type of program is built by writing their source code and that is written by software developers. Software companies hire software engineers and train them to write and build the best computer programs. They mainly focus on their problem-solving algorithms and program functionality to produce a better product. Software vendors also ensure their software products’ security that’s why they hire cyber security experts to test and checkout security flaws in their products. But all these efforts are not enough to completely secure any computer program so they start beta programs to find and solve the actual use-case problems and bugs. Software vendors try to find out every minor or major error in their program and if they fail to detect or miss any kind of software bug that can cause trouble for them and can ruin their entire business. 

    A zero-day attack is an ultimately dangerous attack in cyber security. The term zero-day is used because the software vendor did not know that particular security loop (Software Vulnerability) until and unless that was exploited. As soon as the program is exploited, vendors release the immediate security patch to minimize the damage caused by the zero-day exploit.

What is a Zero-day Vulnerability Or Zero Day Bug?

To better understand a zero-day vulnerability, consider a scenario: suppose someone gifted you a big house that has many floors in it and you have been living there for a while, someday a thief enters your house and cleans many of your valuable items. When you try to trace the thief you find a secret door which you didn’t know about and the thief used that door to enter the house. That secret door is said to be the weak point of your home and this type of weak point is called zero-day vulnerability in cyber security. In simple words, A security flaw or a weak point of a computer program and its vendor is completely unaware till a third party’s impact is called a zero-day vulnerability. After finding a zero-day vulnerability the evil-minded people have two options: they either can report the vendor or they can sell that zero-day vulnerability on dark marketplaces.

Some Most Recent Zero-day Attacks Examples

Chrome Zero-day

    In 2021, many zero-day vulnerabilities were reported in the Google Chrome browser some of them were based upon V8 JavaScript Engine. Google issued some immediate security patches and updates to avoid losses. Below are some examples of zero-day vulnerabilities found in Google Chrome.

CVE-2021-21222 A Heap Buffer Overflow Vulnerability

CVE-2021-21223 An Integer Overflow Vulnerability

CVE-2021-21224 A Type Confusion Vulnerability

CVE-2021-21225 A Out of Bounds Memory Access Vulnerability

Microsoft Windows Zero-day Exploits

    Below are some recent Microsoft Zero-day exploits. Microsoft faced many zero-day exploits that affected many computers across the globe and later some of them were patched also.

CVE-2022-26904: Elevation of Privilege vulnerability used for windows user profile service. This zero-day exploit was released in April 2022 and is in use secretly for six months.

CVE-2022-23277: Microsoft Exchange Server RCE vulnerability (Microsoft Exchange Zero-day Exploit). This vulnerability allows the attackers to exploit through an opened port 443 and exploit to get the RCE sessions.

CVE-2022-29147: This exploit was reported in April 2022 and referred to a spoofing vulnerability of the Microsoft Edge browser which is based on Chromium. The official patches and updates are issued to fix the vulnerability.

CVE-2022-26901: A Remote Code Execution RCE vulnerability of Microsoft Excel. This was also released in the same month and official patches and updates are available.

Zero day Attack Prevention

    To make oneself secure against a zero-day attack, we must follow some cyber hygiene tips. Because the risk of zero-day attacks increases over time every player should play their part to ensure safety and security online. Below are some useful suggestions for both the developers and the consumers to win against this cyber ulcer.

How to Prevent Zero-day Attacks

  • The developers either organizations or individuals must have at least some basic knowledge of security flaws, the latest data breaches, the most recent zero-day vulnerabilities, and their fixes.
  • If multiple teams are contributing to a large-scale program each of their contribution (source code) must be checked to ensure any malicious or irregular activity.
  • If any external library or any other plugin type content is used in the development process that also must be checked otherwise it might lead to similar consequences like SolarWinds 2020 attack.
  • The software houses and developers should hire cyber security experts (penetration testers) to test, and discover zero-day vulnerabilities in their applications before the bad actors find or manipulate them.
  • Software vendor organizations should train and aware their employees of modern cyber threats.
  • Vendors must release an immediate patch if any vulnerability is reported.
  • Also, vendors should take some extra-ordinary steps if they are more likely to be threatened by a zero-day vulnerability and that is visiting the marketplaces and forums where this type of data is being sold. 
  • Customers and consumers must keep their systems up-to-date and never miss the security patches and updates from their vendors.
  • Application customers should always make a backup copy either a hard copy or a cloud copy for recovery after impact.
  • Application customers and consumers should keep themselves updated with the latest data breaches so they can take immediate action if they are found breached.


    The zero-day attacks are extremely dangerous and can lead to the losses of billions of dollars also if a bad guy exploits a zero-day he can ruin the entire echo system of any organisation. These bad guys sell their research on unethical marketplaces, if they don’t do that we probably have more secure digital products. Anyways giant tech companies Google, Facebook, Microsoft, Amazon, and also others are constantly making things better by offering bounties and rewards to the most talented people across the globe to make the internet safer and more secure.

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