What is a Zero-Day Attack?

Security vulnerabilities are an ever-persistent threat that can cause widespread harm. Software in development is beta-tested not just for the user experience, but also for any vulnerabilities that hackers could exploit. These exploits would allow a hacker to gain unauthorized access to alter the device’s functionality running that software.

What is a Zero-Day Attack

The vulnerabilities are not often easy to predict. It’s one thing to beta test in a closed environment with a team of testers versus releasing the product to the world. Committed hackers would often penetrate the security of the product to find exploits to use for malicious purposes.

Zero-Day Attack Explained

Due to the nature of the software development cycle, it’s not always possible to address discovered vulnerabilities in a day or two. A zero-day exploit refers to a security vulnerability that has been made public before the developers of the software could discover it. Because of its unknown nature, developers require time to replicate the exploit and find a solution. Hackers worldwide who partake in the malicious practice of gaining unauthorized access to devices for any number of ill-conceived purposes are always on the lookout for such security loopholes.

Software is a complex pyramid of thousands of lines of code. An exploit is a way for hackers to bypass the security defenses by closely monitoring the software’s functionality to find a vulnerability.

What makes a zero-day exploit dangerous is that it can exist for months without the developer’s notice. Any hacker who has discovered it can leverage or share it with other hackers before it’s made public.

The terms zero-day exploit and zero-day attack are used interchangeably. However, a zero-day exploit is simply a program that has been created based on an existing vulnerability, and a zero-day attack is the result of that exploit.

Known Zero-Day Attacks

A prime example of a Zero-Day Attack and how it can be destructive is the Stuxnet malware, a type of computer Worm that infected Windows-based computers and spread through USB drives and other computers on the network. It wreaked havoc at Iranian uranium enrichment facilities using the Programmable Logic Controllers (PLCs) manufactured by Siemens connected to the PCs to tamper with the centrifuges responsible for uranium enrichment. The malware was particular about where it wanted to be targeted and what it wanted to target. The malware

Stuxnet is largely believed to be a product of the NSA to target Iranian uranium enrichment facilities. It exploited a zero-day vulnerability known as the print-spooler exploit to spread through the network. The malware was discovered in 2010 but is believed to have been in existence since 2005.

Most recently, zero-day exploits were discovered to affect Microsoft Exchange Server by a known hacker group called HAFNIUM which operates from China. The exploits allow the attacker access to email accounts and even install malware for long-term access.

What Happens After a Zero-Day Exploit?

It is called zero-day because that’s how long the software developer has known about this vulnerability. As soon as a vulnerability is discovered, the developer needs to find a way to patch it. The great thing about software is that it can be updated anytime after its release. These updates not only contain improvements to the software but patches for known vulnerabilities. So, don’t hate the updates that your device’s manufacturer or the developer of the application pushes your way.

Security firms worldwide do penetration testing to find vulnerabilities and publish their findings to the respective manufacturers/developers of a product. Governments and clients pay big money to companies for equipment, and they expect iron-clad security from these equipment. It would be disastrous if the equipment used in Defense facilities had some security flaw that went unnoticed. An attack group could write an exploit to gain authorized access.

Microsoft, which ships operating systems and hardware to various clients, including the government, has a global network of security experts under Microsoft Security Intelligence’s wing. Like many other security firms worldwide, the team finds vulnerabilities that hackers can exploit for nefarious purposes.

What Can You Do Against Zero-Day Exploits?

Because a zero-day exploit is new, a patch does not exist to fix the security loophole. It makes zero-day exploits particularly dangerous because weeks may go by before a fix is made available. The COVID-19 virus took a year before vaccines were effective in developing immunity against the virus. Much like the biological agent, a zero-day exploit or a zero-day malware could exist for some time until the counter-measures are prepared.

It is important to keep your device’s software updated to the latest software version. Whether it’s your operating system or the applications running on top, always enable software updates so that you receive a notification as soon as they are pushed out to the public.

Similarly, malware created to utilize zero-day exploits must be discovered by anti-virus developers to analyze the signature and then push it as an update to users.


Never leave the security of your device to unexpected threats. Invest in a robust anti-virus that is updated frequently with new malware signatures, and use a VPN to encrypt communication on public Wi-Fi. There is no definitive way to escape the threat of a zero-day attack; you can follow certain practices to avoid downloading malicious files or visiting malicious links that could exploit a vulnerability dormant in your system.

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