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What is a Zero-day Vulnerability?

You should have heard of the term “zero-day”. But, do you really know what it means? The term “zero-day” means that the developers have “zero” days to solve a problem that has been exposed and may have been already exploited. Cybercriminals seize on that “living” flaws to execute their attack on the same day a weakness is detected. Sometimes an individual who discovers a zero-day vulnerability informs the developer of the risk. However, not all discoveries are that thoughtful. In this article, you’ll about what zero-day vulnerability is and the ways these vulnerabilities are detected.


What is a Zero-day Vulnerability?

A security vulnerability is a code flaw, error, or system misconfiguration within a security system that has the potential to be leveraged by cybercriminals to infiltrate a secure network. Exploitation is the next step in a criminal’s playbook after detecting a vulnerability. An exploit is basically a piece of specially developed software, a chunk of data, or a sequence of commands. Exploits typically take advantage of a security flaw in operating systems, computer systems, Internet of Things (IoT) devices, or other security vulnerabilities.

A zero-day vulnerability, on the other hand, is a vulnerability in a system that has been disclosed but doesn’t have a patch ready. Unpatched vulnerabilities represent a free pass to any target criminals might want to attack. A majority of zero-day vulnerabilities are the result of a software or system architecture bug.


4 Examples of Zero-day Attacks

zero-day exploit examples

Adobe announced (February 2021) security patches for a number of vulnerabilities affecting their products, including a previously unidentified zero-day vulnerability. Adobe didn’t mention the technical specifics of the zero-day vulnerability. Some of the Adobe products that received the patches included Adobe Animate, Adobe After Effects, Adobe Media Encoder, and Adobe InCopy. But, from all the Adobe security updates, Adobe Acrobat Reader had the most fixes, with 14 vulnerabilities.

Microsoft launched (September 2021) an update fixing 66 security vulnerabilities. One of these vulnerabilities addressed a critical zero-day vulnerability. Researchers at Kaspersky found out that the exploit was using a previously unknown vulnerability in the Win32k driver and exploitation relies on a tactic to leak the base addresses of kernel modules. When Microsoft announced the warning, it didn’t have a fix yet and asked users to make sure Microsoft Defender Antivirus was switched on. The discovered exploit was written to support the Windows products running on Microsoft Windows Vista, Microsoft Windows 7, 8, and 8.1, Windows Server 2008 and 2012, and Microsoft Windows 10 (build 14393 and build 17763).

Sony Pictures Entertainment suffered a devastating attack in 2014. Attackers exploited a previously unpatched vulnerability (zero-day exploit) in its computer systems that granted them unrestricted access and allowed them to break into the other parts of the company’s network. Although the details about the vulnerability were being closely held, it remained unclear which software was compromised. The group behind this hack was called “Guardians of Peace”. The group infiltrated Sony’s network and proceeded to release confidential corporate data on public file-sharing sites, including four unreleased featured films, business plans, and contracts.

Operation Aurora is another example (January 2009) of a zero-day attack from China that hit U.S.-based private organizations. It is a targeted malware attack against over 30 major companies, including Google, Morgan Stanley, Juniper Networks, Dow Chemical, and Yahoo, which exploited a zero-day flaw in Internet Explorer. Interestingly, this incident was seen as a milestone in cyber operations history since it enhanced the profile of cyber operations as a tool for industrial espionage. Operation Aurora was a spectacularly sophisticated attack, yet its ultimate consequences remained unclear.


How Zero-day Attacks are Detected?

Zero-day exploit detection techniques include:

  • Statistical-based detection: this approach relies on attack profiles built based on historical data. It sets out “normal” network activity and the traffic that falls outside the scope of normal is classied as abnormal.

  • Behavior-based detection: this is a process where a unique identifier is developed about a known threat, so the threat can be identified in the future. In behavior-based detection, the software is programmed to assess each single line of code and investigate all the potential actions that may be executed by that code.

  • Signature-based detection: this approach depends on signatures made from previously detected exploits. In that context, a signature refers to a typical pattern associated with a malicious attack on a computer network. This detection technique is the critical pillar of security technologies suc h as intrusion detection systems, intrusion prevention systems, firewall, and others.

  • Hybrid-based detection: this detection technique is a blending of different approaches mentioned above.


Final Thoughts

Zero-day vulnerabilities can be the source of some of the most dangerous cyberattacks. An unfortunate reality of cybersecurity is that you can’t foresee every likely attack because some attacks really fly under the radar. The best any organization can do is to conduct the security training and have the necessary tools to remain prepared for the inevitable. The cyber security sector is constantly on the move. For that reason, you need to remain up to date with the very latest cyber security trends and development. Keep an eye on our weekly blog posts and make sure your cyber literacy is on top.