What Is a Zero-Day Attack and How Can You Protect Against It?

What Is a Zero-Day Attack and How Can You Protect Against It?

Malicious characters online are always on the lookout for effective ways to attack individuals or corporations. They have been successful on so many occasions, through brute force or lurking around searching for vulnerabilities.

There are various examples of online threats, including malware, ransomware, phishing, and zero-day attacks. A zero-day attack targets a flaw in software or hardware, which is called a zero-day vulnerability.

Zero-day attacks are particularly dangerous because of the way they occur. However, if you are the average internet user, chances are that you’ve not heard such a term before, or if you have, you may not know precisely what zero-day attacks mean. Well, stick with us, and you’ll learn all there is to know and how to protect yourself from zero-day attacks.

What Is a Zero-Day Attack?

A zero-day attack refers to an incident where cybercriminals or threat actors take advantage of a vulnerability in software before developers can fix it. This kind of security threat is severe because only the attackers are first aware of the vulnerability, and the users or software companies have to play catch-up. When users discover a flaw in such software, they will often report it to the developer, who works on an update with a security patch. It is during the time frame of the update development that zero-day attacks occur.

These attacks are called “zero-day” because the developers have an unspecified number of days to rectify the issue. However, they must develop a patch as soon as possible to limit users’ exposure.

A zero-day vulnerability is a real danger to even the most prominent corporate organizations with elaborate security systems because such systems typically depend on detecting threat signatures. However, a flaw in software might not trigger the alarms.

A compromised software makes you an open target for malware or viruses. They are often referred to as zero-day exploits because they are methods cybercriminals use to attack systems with hidden vulnerabilities.

Common Targets for Zero-Day Attacks

Zero-day attacks seek to exploit vulnerabilities in various targets, which include:

Operating Systems

This is usually the bull’s eye of zero-day attacks because it allows them to hijack user systems, which means endless possibilities for the attacker.

Web Browsers

Web browsers are frequent targets for zero-day attacks. An unknown vulnerability can allow cybercriminals to access files and user accounts linked to the browser or execute scripts.

Large Corporations

Malware can be embedded in emails sent to employees, documents, or other files to exploit zero-day vulnerabilities. Also, attackers target software that corporations use to look for any vulnerability to explore.


Cybercriminals also look out for weaknesses in routers, mobile devices, or gaming consoles which allow them to interrupt your usual activities or search for sensitive information. Hackers can also use compromised hardware to form botnets.

Internet of Things (IoT)

IoT is becoming more common. However, many of these devices lack the facilities for updating their software. This leaves connected devices such as home appliances, sensors, cars, and heavy-duty machinery vulnerable to zero-day attacks.

Examples of Zero-Day Attacks

There have been multiple zero-day attacks on both individuals and organizations, but a couple of infamous incidents include:


Operation Aurora is one of the most audacious zero-day attacks. In 2010, Beijing’s Elderwood Group exploited a vulnerability in Microsoft’s Internet Explorer to carry out a series of coordinated attacks.

These attacks targeted several American-based companies such as Adobe, Yahoo, Google, Symantec, and others. However, the primary target was Google’s source code which the attacks needed to execute more zero-day exploits.


Stuxnet was one of the earliest digital weapons. It is said to have been developed by the United States and Israel. This highly infectious computer virus was used to target Iran’s uranium enrichment plant at Natanz. It exploited several zero-day vulnerabilities to self-replicate and gain special access to systems.

Stuxnet even spread further than the enrichment plants when one of the engineers at the facility connected his work laptop to his home network. This caused more than 15 other Iranian facilities to be attacked and infected by Stuxnet.


Zoom gained a lot of popularity over the last couple of months due to the coronavirus lockdown. It became the top-choice software for video and audio communication as most of the world went into lockdown. However, as more people turned to the software to keep in touch with friends and family, cybercriminals were also searching for a chink in Zoom’s armor.

In 2020, cybercriminals discovered a zero-day vulnerability in the Zoom software for Windows 7 and earlier operating system versions. They launched an attack that allowed them to gain remote access to users’ devices and all the saved files. This was a serious issue because people were conducting businesses more remotely, so many systems had sensitive information stored on them.


In 2014, entertainment giant Sony Pictures fell victim to a zero-day attack. This attack disrupted Sony’s network, bringing it down. The perpetrators also went further to leak sensitive corporate information such as personal information about the company’s employees and their families, salary information, internal conversations, and copies of unreleased Sony films. They published the information on file-sharing sites.


In 2011, hackers attacked the security firm RSA’s network. They took advantage of a vulnerability in Adobe Flash Player. The cybercriminals were able to gain access by sending RSA employees emails with Excel spreadsheets embedded with a Flash file. The moment an employee opened the file, the hackers could control their computers, infiltrate their systems, and steal sensitive information. Some of the data they stole was related to RSA’s SecurID two-factor authentication products.

How To Protect Yourself From Zero-Day Attacks

Zero-day vulnerabilities are usually hard to detect until an attack occurs and users raise the alarm. However, here are a couple of helpful tips that can help you stay more protected and reduce the likelihood of you or your organization becoming victims of a zero-day attack:

Set Up a Firewall

One of the most effective ways of enhancing your security is using a firewall. A firewall regularly scans for threats like viruses and malware to make sure you don’t fall prey to attacks.

Enabling a firewall varies across operating systems and devices, but it is pretty easy to set up. You’ll find the option in the security or privacy settings section of your device.

Use Advanced Email Security

When dealing with zero-day attacks, you need to act fast and be proactive. There are various top-standard, reliable email security options that are very effective at protecting against zero-day attacks and can quickly fix zero-day vulnerabilities. Such services are valuable investments.

Keep Your Applications and Operating System Updated

Developers frequently release updated versions of applications and operating systems to eliminate possible bugs that they missed earlier and to boost security. However, the average user might think these updates are not necessary because they don’t notice much of a difference, or everything seems to be just fine as it is. 

However, installing the latest versions of your apps or operating system is essential if they are available. This will reduce the possibility of zero-day attacks happening.

Implement Network Access Control

Network access control blocks unauthorized access to your personal or work networks. This is also a great way to reduce the possibility of any security breach, including zero-day attacks. Also, if an attack occurs, it will limit how much access hackers will get.

Limit The Applications You Use

One effective form of zero-day exploit is malware. So, when you have so many applications running on your device, you are more exposed to zero-day attacks. So, only use essential apps to reduce the vulnerabilities in your system.

Use IPSec Protocol

IPsec is a very secure protocol. It enables encryption and authentication on all types of traffic, making it possible for your devices to identify and isolate threats quickly. Using IPsec is usually more manageable with a VPN because there’s little or no configuration necessary to implement it. ExpressVPN is your best bet because it supports IPSec and offers an extra layer of security and privacy.

Stay Updated on Cybersecurity News

Make an effort to stay abreast of all the latest news and trends that relate to cybersecurity. That way, you don’t miss out on vital information on actions that can protect you online. In addition, our website has tons of valuable information about cybersecurity you can always check out.


Zero-day attacks are amongst the worst kinds of cybersecurity threats because they occur without warning. By the time you discover a vulnerability, hackers might have had their way with your network and data on your system. 

The best way to avoid these attacks is to be vigilant and take some precautionary measures. Follow the steps we have pointed out in this article, and you will most likely never experience a zero-day attack.

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