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What is a Zero-Day Vulnerability? Definition and Mitigation

Published on Dec 21 2022

Digitizing operations reduces complexity and increases efficiency. Technology creates new vulnerabilities, making the company vulnerable to cybercriminals. Companies frequently use patch deployment to protect their systems, which is convenient if it only needs to be done once. 

Although no fool proof protection method exists, proactive steps can be taken to minimize the results of cyber-attacks. This article defines Zero-Day vulnerabilities in detail and advises how to mitigate them. 

What Is a Zero-Day Vulnerability? 

Software vendors perform continuous vulnerability checks. To fully protect their users, they work to address newly discovered vulnerabilities and release updated patches quickly. The phrase "Zero Day" refers to the developers' limited time to patch these newly discovered vulnerabilities. 

The risk arises when cybercriminals identify system weaknesses before the vendors of the software and use them to launch cyber-attacks. Three terms should be defined in this context: 

Zero-day (or 0-day) Vulnerability 

The term "zero-day vulnerability" refers to a vulnerability in a software, system or device that has been disclosed but is not yet patched. Users have no protection against such cyberattacks because no patch or mitigation is available. 

Zero-day exploit 

A zero-day exploit is the technique or tactic a malicious actor uses to leverage the zero-day vulnerability to attack a system. 

Zero-day attack 

A zero-day attack uses the zero-day exploit to infiltrate the vulnerable system, potentially resulting in considerable damage and data theft. 

The zero-day vulnerability's hidden nature makes it very destructive. Zero-day attacks are designed by cybercriminals to spread quickly and infect as many networks and systems as possible. The main risk is that the zero-day vulnerability provides the attackers with a lot of time, either by remaining undetected or because it takes experts several days or even months to analyse attack information. 

Zero-Day Vulnerability Mitigation Best Practices 

There is no way to defend the company against a specific exploit before it happens because the zero-day vulnerability is unknown beforehand. Here are some methods to limit its risks, though: 

1. Preventative Security Measures 

Firewalls and antivirus software are the best tools for preventing attacks from happening in the first place, which is the main goal of defense. A firewall keeps the track of all incoming and outgoing network traffic to prevent unauthorized access. It prevents malicious traffic that might aim for a security vulnerability and result in a zero-day exploit. 

While antivirus software detects malware using a signature database, many cutting-edge antivirus programs can frequently spot malicious intent from observed system behaviour. 

> What Is Multifactor Authentication (MFA)? Why We Need It And How Does It Work?

2. Patch Management 

One of the best approaches to protect against cyberattacks is to keep all software up to date. To maintain system security, software vendors release "Patches" or updates regularly to address new vulnerabilities. Patch management ensures patches are routinely applied and are not missed; while it cannot prevent zero-day attacks, it can reduce the exposure window. 

3. Limited Access 

Containing the zero-day attack is crucial to reduce its impact. By restricting user access to essential data and systems, the potential cyberattack will only harm a small portion of the system the compromised account can access. Reduced damage will make system restoration easier when regular backups are used. 

4. Good Data Backup 

When an incident occurs, backups will be valuable and occasionally priceless. To mitigate the effects of unexpected cyberattacks like zero-day attacks, it is important to plan an efficient backup strategy that offers regular system backup and stores copies of those backups on local or cloud servers in various locations. 

5. Preparing An Incident Response Plan 

There is no need to panic; the zero-day attack will certainly cause a lot of confusion. Instead, emergency team members with clearly defined roles and recovery procedures will maintain business operations, minimize the attack's effects, and contain it as quickly as possible. This is done by creating an emergency plan containing attack identification and contamination. 

6. Intrusion Protection 

A network intrusion protection and detection systems (IPS and IDS) can keep an eye on the companies' networks for unusual activity as an additional layer of security that works with antivirus and firewalls. Network Intrusion Protection System (NIPS) tracks regular patterns of network activity throughout the entire network and alerts the system to lock down the firewall whenever they notice any unusual traffic or events. 


Zero-day vulnerabilities can be extremely damaging to most businesses because they are impossible to prevent, even with standard safeguards. However, the damage can be minimized with the proper precautions, such as up-to-date security software and firewalls. Furthermore, having a backup and an emergency plan in place will help with system restoration and risks mitigation after an attack of such nature. 

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