Zero-Day Vulnerabilities: What are They and Why Should You Worry About Them?

Quick Summary: Zero day vulnerability poses serious security challenges. It makes your systems and applications susceptible to cyberattacks with unaddressed loopholes. Keep reading to know everything about it and how you can prevent it to mitigate security risks.

While developers create software applications with greater attention and best practices, some bugs and loopholes escape their eyes. These loopholes can later be discovered before they are patched by a malicious actor who can exploit them for unethical activities.

This is what we consider as Zero-day vulnerabilities. They offer a golden opportunity to cybercriminals, enabling them to exploit unaddressed software weaknesses. These vulnerabilities keep software applications susceptible to cyberattacks until patched.

Hence, it becomes important to find and address them at the earliest. A comprehensive vulnerability assessment is an effective method to mitigate these risks and keep your software applications safe. Keep reading to know more about zero-day vulnerabilities, exploits, and attacks as well as other crucial information.

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Zero Day Vulnerability, Exploit, and Attack

A Zero-day vulnerability also written as 0-day vulnerability or day 0 vulnerability, is a type of security flaw in software, systems, and firmware that is yet to be patched. It was unknown to the vendor or developers of the software and has been recently discovered.

It is termed as 0-day because it has been found recently, so developers have “zero days” to patch it before a cyberattack. This vulnerability was hidden for the time it wasn’t discovered and could have been exploited by a cybercriminal.

These vulnerabilities can cause more damage because there is no defense or patch presently available for them. Cybercriminals can take advantage of these security flaws to conduct cyberattacks and steal confidential data.

In a recent attack, more than 40,000 CISCO devices have been compromised by exploiting zero-day vulnerability. It was a Web UI-based security flaw that resulted in unauthorized privilege escalation.

When it comes to zero-day vulnerabilities, there are terms like Zero-day exploit and Zero-day attack widely used in this context. What are Zero day exploits and Zero-day attacks? Let’s understand these terms.

• Zero day exploit: It refers to the technique a cybercriminal uses to conduct a cyberattack using 0-day vulnerability.
• Zero day attack: It refers to the cyberattack that a cybercriminal has initiated using 0-day exploit before the 0-day flaw has been patched.

Based on the above definitions, you know the distinctions of zero day vulnerability vs zero day attack vs zero day exploit. Each of them refers to a different concept but depends on each other.

Why are Zero Day Vulnerabilities Considered Most Dangerous?

Cybercriminals often look for zero-day vulnerabilities because currently there is no patch available for them. In fact, it can take many days, weeks, or months before software vendors or developers become aware of the 0-day vulnerability and release a patch. Till that time, cybercriminals can cause havoc by misusing this weakness.

Bugs and vulnerabilities in software applications are not rare and they even reach the production environment. In the best-case scenario, these vulnerabilities are first found by software developers or vendors. Once they are found, a patch is provided, or a new version of a software application is released to fix it.

In the worst-case scenario, a cybercriminal can find the vulnerability before the vendors and developers. In this situation, the cybercriminal can leverage zero day exploits to gain unauthorized access to the target application and steal confidential data.

Let’s see why 0-day vulnerabilities are dangerous for your organization.

High Chances of Success

Common vulnerabilities like OWASP Top 10 are already recorded, and it is possible to detect them using a basic vulnerability scanner. On the other hand, day 0 vulnerabilities are recently disclosed or not known. Therefore, they have a higher chance of success. There is a constant threat until no viable patch is available for it.

Steal Data Insidiously

You can lose your data under your nose due to zero-day threats arising from zero-day vulnerabilities. Cybercriminals can conduct attacks like remote code execution, denial-of-service, credential theft, and more to do damage. A similar case occurred in 2019 in Eastern Europe, when cybercriminals took advantage of a Microsoft Windows vulnerability to run arbitrary code. As a result, they gained privileged access to the affected systems. Government institutions were their primary targets.

Risk of APT

Advanced Persistent Threat or APT is a targeted attack that lasts for a longer time. Usually, cybercriminals can exploit 0-day software weaknesses for a single attack like stealing confidential data. In some cases, they also perform targeted attacks by gaining access to the victim’s network and continuing it for an extended time. It is widely conducted for espionage and criminal activities.

Cybercriminals can use sophisticated attack techniques to do severe damage to the victim. Regular security assessment with dynamic application security testing and penetration testing can help you avoid such risks. With testing, you can uncover potential risks and strengthen your security posture.

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Real-World Examples of Zero-Day Vulnerability

There are many real-world cases when cybercriminals utilized day zero vulnerabilities to conduct cyberattacks as shown below.

Log4j

Log4j, also known as Log4Shell vulnerability, showed how risky open-source software can be when used without security precautions. The CVE record is CVE-2021-44228 for this threat. It affected many users including organizations and individuals. It is associated with the Apache Log4j logging library and is a good example of zero-day vulnerability. It was discovered in 2021.

Cybercriminals could gain unauthorized access to systems by remote code execution attacks exploiting this vulnerability. They exploited the log message parameters with this security flaw. It enabled them to get complete control of a target device. The number of cyberattacks increased in 2021 due to this security flaw.

Severity Level: High (Critical Vulnerability)

Patch Available: Yes

Apple iOS Kernel and RTKit Vulnerabilities

Apple has recently patched two critical zero-day vulnerabilities that were found in the iOS kernel (CVE-2024-23225) and RTKit (CVE-2024-23296) affecting iOS devices. According to reports, these flaws allowed cybercriminals to bypass kernel memory protection by exploiting kernel read and write capabilities with arbitrary code.

This flaw affected lots of iOS devices, including the iPad 5^th generation, iPhone 8, iPhone 8 Plus, iPhone XS, and iPhone X, among others.

Severity Level: High

Patch Available: Yes

Windows SmartScreen Vulnerability

Cybercriminals exploited the Microsoft Windows SmartScreen vulnerability (CVE-2024-21412) to install fake software on victim’s computers. This weakness allowed them to bypass the SmartScreen protection. Microsoft Defender SmartScreen is a Windows feature that helps to protect against phishing and malware threats.

Severity Level: High

Patch Available: Yes

Understanding Zero-Day, 1-Day, and N-Day Vulnerabilities

Day 0 vulnerabilities start a cat race between the developers and cybercriminals for who finds it first. Just like SDLC, there is a lifecycle for vulnerabilities that determines their position, like whether it is zero-day, 1-day, or N-day vulnerability. Let’s understand this with the following timeline graph.

In the above image, V(c) denotes the time when a vulnerability is introduced into the source code. 0-day falls under the T1 timeline when the vulnerability is disclosed, but there is no patch available for it, the time from V(d) to V(p).

One-day vulnerabilities occur when there is a patch or remediation available for it, but it is not yet applied. Refer to the T4 timeline in the graph image. It denotes the time after V(p).

Often, these are also referred to as N-day vulnerabilities because patching them requires a longer time than a single day. According to Statista, the average time it takes to patch vulnerability is between 88 and 208 days.

So, the average mean time to patch or MTTP provides a long enough window for cybercriminals to exploit it. Thus, it is called N-day vulnerability.

How Can You Defend Against 0-Day Vulnerability?

Preventing a zero-day attack arising due to 0-day vulnerabilities is quite challenging because releasing a patch takes some time. The best way would be to defend your software applications from this kind of threat. It involves ensuring a robust security posture and following the best security practices. It can help to mitigate the risks. Let’s see some ways to protect your applications.

Vulnerability Scanning

You need a reliable DAST scanner to catch 0-day security weaknesses. These scanners can uncover zero-day vulnerabilities by performing dynamic tests on the target applications. For example, a DAST solution can perform simulated attacks on your web application and identify weak spots, just like a cybercriminal. It can help automate web app security testing and find potential vulnerabilities by testing it from the front end.

Timely Patching

Apply patches as soon as they are available for third-party software components and frameworks used with your application. Keeping these components up to date can help to keep 0-day vulnerabilities at bay and avoid zero-day attacks. Timely patching will help you minimize the window for attacks and avoid data breaches.

Best Security Practices

Following the best security practices like strong passwords, encryption, input validation, sanitization, and more can help protect your applications. You should keep an eye on the latest cybersecurity trends to get constant updates about new threat vectors and approaches for security.

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In Conclusion

With an ever-growing threat landscape, protecting your software applications has become challenging. You need a better strategy to safeguard your data than adding new layers of security. Any weak spot in your applications can undermine the whole security mechanism.

Identifying vulnerabilities like zero-day can be difficult as they are hard to detect. However, using the best vulnerability scanner like ZeroThreat can help you discover such weak spots. It uses an AI-powered crawler to scan your web apps and APIs. It offers faster scanning speed and doesn’t require configuration.

You can try it for free and detect a wide range of security loopholes like OWASP Top 10 and CWE-25 with almost zero false positives.