Zero day vulnerebilities are defined as “A weakness in the computational logic (e.g., code) found in software and hardware components that, when exploited, results in a negative impact to confidentiality, integrity, or availability. Mitigation of the vulnerabilities in this context typically involves coding changes, but could also include specification changes or even specification deprecations (e.g., removal of affected protocols or functionality in their entirety).” – The CVE system.


1.Heartbleed (2014)

Vulnerability: Affecting OpenSSL, a widely used open-source cryptographic library, Heartbleed allowed attackers to read sensitive data from the memory of millions of web servers. Impact: It posed a significant threat to the confidentiality of data, Heartbleed prompted widespread patching efforts and raised awareness about the importance of securing open-source software.

2.WannaCry Ransomware (2017)


Vulnerability: Exploiting a Microsoft Windows SMB vulnerability known as EternalBlue, WannaCry propagated rapidly across networks, encrypting files and demanding ransom payments. Impact: WannaCry affected hundreds of thousands of computers globally, including critical infrastructure such as healthcare systems. The incident highlighted the need for timely patching and the risks associated with unpatched systems.

3.Meltdown and Spectre (2018)


Vulnerability: These vulnerabilities affected a wide range of processors, including those from Intel, AMD, and ARM. They allowed attackers to potentially access sensitive data, including passwords. Impact: Meltdown and Spectre represented a new class of hardware-based vulnerabilities, emphasizing the complexity of securing modern computer architectures. Mitigations involved both software patches and firmware updates.

4.BlueKeep (2019)


Vulnerability: Affecting Microsoft’s Remote Desktop Protocol (RDP), BlueKeep allowed for remote code execution without user interaction. Impact: Given the potential for a wormable exploit, BlueKeep raised concerns about the rapid spread of malware across unpatched systems. It underscored the importance of securing remote access protocols.

5.Zerologon (2020)


Vulnerability: Zerologon affected Microsoft Windows Netlogon, allowing attackers to gain administrative access to a Windows domain controller. Impact: The vulnerability posed a severe risk to network security, potentially leading to unauthorized access and privilege escalation. Timely patching was crucial to mitigate the risk.

The Stealthy Nature of Zero-Day Threats


The primary characteristic that makes Zero-Day Vulnerabilities so insidious is their stealth. Unlike known vulnerabilities, there is no established defense mechanism when a zero-day flaw is exploited. Cybercriminals leverage this advantage, often deploying targeted attacks before security patches can be developed and distributed.