In Netflix's latest hit series, a fictional president—played by Robert De Niro—faces a devastating Zero-Day attack that threatens national security. While it may be captivating on screen, Zero-Day attacks are, in reality, extremely dangerous threats.

Not only can they have major consequences for organizations, but they have also become an increasingly widespread threat. Their numbers are constantly rising, and with the rise of artificial intelligence and machine learning, they are becoming even harder to defend against. Attackers can now automate and adapt their strategies in real time.

In 2021, a Zero-Day attack hit Microsoft Exchange Server, used by millions of businesses. Several Zero-Day vulnerabilities were exploited to attack email accounts while installing malware. The result: data from thousands of companies was stolen, severely disrupting their operations.

In this article, we explain how these attacks work and what strategies you can implement to protect yourself.

I. What are Zero-Day attacks?

The term Zero-Day attack is used when an attacker exploits a vulnerability that has not yet been discovered. This vulnerability can be in software or hardware. Since it has not yet been identified, no patch has been developed. Hence the name "Zero-Day": the developer has had zero days to fix the flaw.

There is not just one type of Zero-Day attack. They can take various forms (malware, viruses, worms, etc.) that vary in intensity and mode of action once they have infiltrated. What characterizes a Zero-Day attack is not its form, but the exploitation of the unknown vulnerability.

These attacks are particularly dangerous because the attackers have every advantage. Since the vulnerability has not yet been discovered, the attack completely catches the victim off guard. And without a patch to fix it, the impact can be significant.

They are all the more problematic because they can go unnoticed for long periods, as they are difficult to detect. This is even more true when the victim relies on traditional cybersecurity solutions (such as antivirus software), which are based on already known threats.

II. How do they work?

A Zero-Day attack begins as soon asa hacker identifies an unknown vulnerability to exploit.

The attack generally targets critical parts of the system: web browsers, operating systems, applications, etc. The hacker creates or uses an exploit to take advantage of the flaw.

This exploit, known as a Zero-Day exploit, can take various forms and vary in complexity: a simple script, a phishing attempt, remote code execution, privilege escalation, and more. The attack continues as long as the flaw remains undiscovered. Some threats can remain undetected in the victim's system for a long time, which is why some Zero-Day attacks are so severe.

The attack ends either when the hacker has achieved their goal or when the suspicious activity is detected.

III. Steps to prevent Zero-Day attacks

The primary cybersecurity strategy to adopt against Zero-Day attacks is prevention. Since it is impossible to predict which vulnerability will appear, all avoidable weaknesses must be addressed. Here are some measures to take:

• Update all your software regularly and automatically to benefit from the latest patches
• Ensure rigorous network segmentation: divide your network into isolated segments to limit the impact of an attack
• Conduct regular security audits to detect potential entry points
• Implement a comprehensive backup strategy, particularly against ransomware
• Train employees to minimize human error as much as possible

These simple yet crucial actions significantly reduce potential vulnerabilities in your IT infrastructure, and consequently, the risks of Zero-Day attacks. However, these steps alone are not enough to guarantee your security. It is essential to have a robust, multi-layered cybersecurity strategy.

IV. Proactive cybersecurity tools to protect you

Even though the vulnerabilities exploited in a Zero-Day attack are unknown, there are cybersecurity tools capable of developing a proactive defense against these types of threats.

Advanced threat detection tools are essential. EDR (Endpoint Detection and Response) solutions can detect previously unknown threats. Their principle is simple: continuously monitor your IT infrastructure to spot any abnormal behavior. When a vulnerability is exploited, unusual behavior appears—and is then detected. The EDR can then neutralize the threat in real time.

What sets EDRs apart is their ability to accurately detect suspicious behavior. EDRs that integrate AI, machine learning, and behavioral analysis go even further. Thanks to these technologies, EDRs learn from ongoing activities, detect patterns, and identify new or unknown attacks. This is how TEHTRIS EDR works, leveraging our AI, CYBERIA, to provide you with a robust defense against Zero-Day attacks and other threats.

Furthermore, Deceptive Response solutions are becoming essential in a proactive strategy. These tools create decoy resources placed throughout your network. When an attacker interacts with one of these decoys, their presence is revealed and the attack can be stopped. This is particularly useful against Zero-Day attacks, as it works even if the exploited vulnerability is unknown.

TEHTRIS has developed its own Deceptive Response solution, which provides you with key insights, prevents future attacks, and strengthens your overall cybersecurity posture.