Zero Day: What is a Zero-Day Vulnerability and Why is it Dangerous?

Zero day, or 0day, is frequently discussed in various blogs and profiles across the internet, alerting about new and dangerous exploits. But do you really know what a zero day exploit, attack, or vulnerability is?

And furthermore, how can you protect yourself and why can it be so dangerous?

Zero day attacks usually occur when cybercriminals get ahead of the game and exploit vulnerabilities that are not yet known. This means they catch companies and their systems completely unprepared.

However, this doesn’t mean these attacks are unavoidable. There are ways to defend ourselves, and that’s what we’ll explore in today’s article!

Today, we will cover how zero day exploits work, why they are dangerous, and how you can identify and avoid them.

Let’s get started!

What is Zero Day?

Let’s start from the beginning. A zero day, or day zero, can be described as a previously unknown security flaw in software or hardware that cybercriminals exploit to breach systems.

Despite different terms, the origin is the same. This term was created to emphasize the seriousness of the problem.

After discovering this zero day vulnerability, developers have literally zero days to fix the error before it becomes an urgent issue.

When you become more familiar with zero day exploits, you might hear them referred to as “zero day vulnerabilities” or “zero day attacks.”

However, there is an essential distinction between these terms:

• Zero-day exploit: Refers to the method hackers use to attack the software.
• Zero-day vulnerability: Refers to the undiscovered flaw in your system.
• Zero-day attack: Refers to the action hackers take when they use the vulnerability to breach your system.

The term “undiscovered” is crucial when discussing zero day vulnerabilities, as the vulnerability must be unknown to the system creators to be considered a “zero day vulnerability.”

A security vulnerability ceases to be a “zero day vulnerability” once developers become aware of the problem and release a patch.

It’s Not Just You: Software is Vulnerable

Relax, this doesn’t only happen to you or your company.

Software is not perfect and yes, it is always vulnerable. Even the browser you’re using to read this article—whether it’s Chrome, Edge, Firefox, or any other—certainly has bugs.

In many cases, these bugs are not harmful, perhaps causing the browser to malfunction or crash, but not all of them are security flaws. Security flaws occur when an attacker who knows about the bug can create an exploit that uses the bug in the software to gain access to your system or information.

Naturally, some software is more vulnerable than others, and this is not a problem with your choice or the entire security system of your company. It is common.

At one point, Java had an endless stream of vulnerabilities that allowed sites using the Java plugin to escape the Java sandbox and gain full access to your machine. Exploits that compromise Google Chrome’s sandbox technology are much rarer, though even Chrome has zero day vulnerabilities.

Now let’s understand how zero day attacks work. Keep reading!

How Zero Day Attacks Work

You may have noticed that there are certain specifications needed to carry out these attacks.

Since most of these attacks are different from each other, they generally work like this:

1. Step 1: Developers create a system. It contains a zero day vulnerability that they are unaware of.
2. Step 2: When the system is activated and goes live, the cybercriminal discovers the vulnerability by analyzing the system.
3. Step 3: The attacker creates, writes, and executes malicious code to exploit the vulnerability and potentially breach the system.
4. Step 4: Users accessing the system or developers notice the serious problem, and the developers then fix the problem using a patch.

There are also cases where criminals are faster at exploiting vulnerabilities immediately after discovering them.

These exploits are highly sought after as they can be sold on the dark web for large sums of money. Once discovered and fixed, the exploit is no longer referred to as a zero day threat.

Who Exploits Zero Days?

There are not a few malicious actors who exploit zero day attacks. In fact, they fall into different categories based on their motivations.

Here are the categories:

• Virtual criminals: Their sole motivation is financial gain.
• Corporate espionage: Hired by competitors, cybercriminals spy on companies to obtain confidential information and pass it to the hiring parties.
• Cyber warfare: At a diplomatic level, these attacks are common in countries or political actors that spy on or attack another country’s virtual infrastructure.
• Hacktivists: Cybercriminals motivated by a political or social cause who wish to bring attention to their attacks to highlight their cause.

Now that you know what zero day is, how it works, and who typically exploits it, we come to an important point: how to identify and prevent it.

Pay attention to the next section!

How to Identify a Zero Day Attack

As mentioned earlier, each of these attacks has its own particularity, so unfortunately, there is no perfect plan to detect them.

However, there are ways organizations can identify attacks and act quickly.

Here are three methods you can implement:

1. Conduct a Comprehensive and Periodic ScanPerforming this scan helps in the process of searching for zero day vulnerabilities in the system. Once a weakness is found, you can work to fix it before hackers can exploit it.Vulnerability scanning can be an independent activity or a regular part of your development process.Many organizations also choose to outsource their vulnerability scanning to specialized cybersecurity companies.
2. Collect and Monitor User ReportsGiven the constant interaction of users with your system, they might detect potential issues themselves.Therefore, it’s advisable to track user logs, reports about suspicious emails, pop-ups, or notifications about password attempts. Any abnormal activity should be investigated.
3. Monitor Your Software’s PerformanceWhen a cybercriminal gains access to a system through malware, increased network traffic can slow down the victimized system’s connection to the internet. Therefore, monitoring network statistics can help you spot an attack as it happens.When someone gains access to your system through a vulnerability, the injected code may slow down your program, alter its functions, or take resources offline.Naturally, you might identify a zero day attack by observing significant or unexplained changes in your system.

Protection Against Zero Day Attacks

These attacks are alarming because there is no prior warning. Unfortunately, we cannot avoid these attacks entirely, but we can identify them (as you saw earlier) and protect ourselves from them.

So, what can we do to protect ourselves from zero day exploits? The answer is in this list:

• Use Secure Web HostingHackers breach hundreds of thousands of sites every day. Since hackers can compromise your site through plugins, themes, or outdated core versions of platforms like WordPress, WordPress sites are significant targets. Therefore, ensure you have a good hosting tool that guarantees security.Fortunately, you can protect your organization by using a secure hosting provider.
• Implement the Principle of Least PrivilegeThis regulation requires that individuals in your organization have access only to the data, hardware, and software necessary to perform their regular work tasks.The principle of least privilege creates fewer entry points for hackers who use vulnerabilities to obtain access credentials, limiting the number of people with administrative access to each system.
• Switch to DevOps DevelopmentDevOps is an approach that uses a continuous development system to constantly update programs.It can help you strengthen your security against zero day exploits by forcing you to continuously update and change your system.If you want to learn more about DevOps development, be sure to read the guide we released on the topic: DevSecOps: The Importance of Considering Security from the Start.

Additionally, don’t forget:

• Reduce your attack surface
• Keep your software updated
• Stay ahead of cybercriminals, invest in Brazil’s top Bug Bounty platform!

Zero day attacks are becoming increasingly common and a natural concern for organizations worldwide. Therefore, having a service that prevents these attacks is essential.

BugHunt is in the information security market for this purpose! We are Brazil’s first Bug Bounty platform, having reported over 2,500 vulnerabilities to partner companies and helping to strengthen their systems’ security.

Don’t let cyberattacks cause damage—get ahead of the curve and check out our platform!