By Ayo Onikoyi

Olusegun Adedeji is a seasoned network and cybersecurity engineer with over 8 years hands-on experience.

During his career growth, he has functioned in different capacities in some of the famous growing technological inclined organizations and has a few articles tied to his belt.

In this interview, he took a deep dive into a vulnerability called zero-day attack, what it means, how it works and the effect it poses to our modern-day activities in the technological space.

Can you define a zero-day attack and explain why it poses a significant cybersecurity threat?
A zero-day attack exploits a software or hardware vulnerability that is unknown to the vendor or developer.

Since there are no available patches or defenses, attackers can exploit the flaw before the vendor has a chance to fix it. This makes zero-day attacks particularly dangerous because traditional security measures like firewalls and antivirus programs cannot detect or block them.

How are zero-day vulnerabilities typically discovered by attackers?
Attackers use various methods to discover zero-day vulnerabilities. Techniques include reverse engineering software to uncover flaws, fuzz testing, where random data is inputted into programs to trigger unexpected behavior, and monitoring software updates for clues about underlying vulnerabilities. Additionally, some cyber criminals purchase or sell zero-day exploits on dark web marketplaces.

Can you explain the lifecycle of a zero-day vulnerability?
Certainly. The lifecycle begins when a vulnerability is introduced into a system, often during software development. The next phase is discovery, where attackers or researchers find the flaw. If attackers discover it first, they may develop an exploit and launch a zero-day attack. Once the vendor becomes aware of the vulnerability, they start developing a patch. Finally, after the patch is released, the vulnerability is no longer considered zero-day, although unpatched systems remain at risk.

How do attackers weaponize zero-day vulnerabilities in real-world attacks?
Attackers craft custom exploit codes targeting the vulnerability and deliver it through phishing emails, malicious websites, drive-by downloads, or infected software updates. Once executed, the exploit can give attackers unauthorized access, allowing them to steal data, install malware, or disrupt services. Advanced Persistent Threat (APT) groups often use zero-day exploits in targeted attacks against high-value organizations.

What was one of the most impactful zero-day attacks in history?
The Stuxnet worm discovered in 2010 is one of the most impactful zero-day attacks. It exploited multiple zero-day vulnerabilities in Microsoft Windows to target Iran’s nuclear centrifuges, causing physical destruction. It highlighted how zero-day attacks could bridge the gap between cyber and physical systems, creating real-world consequences.

How can organizations defend against zero-day attacks despite the unknown nature of these vulnerabilities?
Organizations can’t prevent zero-day vulnerabilities, but they can minimize the risk. Implementing advanced threat detection tools like Endpoint Detection and Response (EDR) systems, using behavior-based security solutions, conducting regular vulnerability assessments, practicing network segmentation, and applying the principle of least privilege are critical. Additionally, staying informed through threat intelligence feeds can help identify early indicators of zero-day exploitation.

How do software vendors and security researchers handle zero-day vulnerability disclosures?
Responsible disclosure involves security researchers privately reporting vulnerabilities to the vendor, giving them time to develop and release a patch. Vendors then issue security advisories and updates. In contrast, some researchers use full disclosure, where vulnerabilities are made public immediately, pressuring vendors to act quickly but risking exploitation.

What is the role of the black market in the proliferation of zero-day exploits?
The black market plays a significant role in zero-day exploit proliferation. Cybercriminals, hackers-for-hire, and even nation-states buy and sell zero-day vulnerabilities through dark web forums. Prices can range from a few thousand dollars to millions, depending on the target platform’s popularity and the exploit’s effectiveness.

Are governments involved in the use of zero-day exploits?
Yes, many governments stockpile zero-day vulnerabilities for intelligence gathering, surveillance, and cyber warfare. While this can enhance national security, it also raises ethical concerns. If these vulnerabilities are leaked or stolen, they could be weaponized by malicious actors against civilians and critical infrastructure.

Finally, how do zero-day attacks influence global cybersecurity policies?
Zero-day attacks have driven governments and organizations to improve cybersecurity frameworks, enforce stricter software development practices, and invest in rapid patch deployment. Initiatives like bug bounty programs encourage ethical hacking to uncover vulnerabilities. Additionally, international discussions around cybersecurity norms and vulnerability equity processes (VEP) aim to balance security needs with public safety.