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Cyren Security Blog

The Cyren Security Blog is where Cyren engineers and thought leaders provide insights, research and analysis on a range of current cybersecurity topics.

What is a Zero-Day Phishing Attack? Identifying Vulnerabilities & More

“Zero-day” is a term that broadly describes a series of recently discovered cybersecurity vulnerabilities hackers utilize to attack systems. This term, “zero-day”, often refers to the fact that the developers have just learned about the flaw. Hackers will exploit flaws they find before developers even have a chance to address them. This can also be associated with the fact that there are “zero days” to fix the exploit.

Similarly, a zero-day phishing threat in particular is one that has not been seen before and does not match known malware signatures. This can make it almost impossible to detect with traditional signature-matching solutions.

In this post, we explore the risk of zero-day phishing threats and how your business can protect against them.

So, What Exactly is the Risk of a Zero-Day Phishing Threat?

Cyber threats are continually increasing with dozens of new zero-day phishing threats originating each and every day. Protecting your network, as well as applications, and data involves having an advanced threat prevention system in place where you can test untrusted files, links, and emails before they reach your email network.​ Because vendors are unaware of what a zero-day phishing attack can do, they can often get through traditional phishing software, where no patch exists to stop these attacks. Zero-day phishing attacks pose higher risks to users for the following reasons:

  • Speed: Cybercriminals often race to exploit vulnerabilities so they can cash in on their schemes as quickly as possible.
  • Response Time: Vulnerable, exploited systems will remain exposed until a patch is created by the vendor to stop these attacks from happening.
  • Hyper-Targeted: Zero-day vulnerabilities typically involve highly-targeted phishing attacks. These kinds of attacks can focus on old vulnerabilities or completely new ones.

Who Is Being Targeted in Zero-Day Phishing Attacks?

The targets, while highly focused on in an attack, can range significantly. For this reason, any organization using email can be a target for zero-day vulnerability or attack. This can range from massive corporations like Microsoft, which was famously attacked in 2021, to much smaller organizations. If you use email for any kind of communication, your network is a potential target for zero-day vulnerability.

How to Protect Against Zero-Day Phishing Attacks

Protecting against zero-day phishing attacks can be extremely difficult. Here are some of the best methods for protecting your business.

  • Virtual Local Area Networks: Using virtual local area networks can help you segregate areas of the network.
  • IPsec: Implementing IPsec can help you apply encryption and authentication to your network traffic.
  • Network Access Control: Using network access control can help prevent machines from going rogue and gaining access to important parts of enterprise environments.
  • Protect Wi-Fi: Locking down on wireless access points, or using a security scheme can help protect against wireless-based attacks.
  • Keep Everything Up-To-Date: Keeping all your systems patched and up to date is very important. Even though patches won’t stop one of these zero-day attacks, keeping your network resources fully patched can make it much more difficult for a phishing attack to succeed. When a zero-day patch becomes available, you will want to apply it as soon as possible.
  • Scanning: Performing regular vulnerability scannings can help you lock down against any enterprise network vulnerabilities discovered.
  • Limit Apps: Limiting your applications can help you limit the amount of data you’re putting at risk.
  • Firewall: Using a firewall can help you monitor and block any suspicious activity, like zero-day phishing attacks.
  • Education: Educating yourself on zero-day phishing attacks and seeking out different solutions is important to the health of your network.

Examples of Zero-Day Attacks & Exploits

Zero-day exploits happen more often than you think, especially for large companies. Here are a few of the most notable attacks in the past few years.

  • Google Chrome in 2021: Google Chrome was the victim of several zero-day threats, which were attributed to a JavaScript bug.
  • Zoom in 2020: Hackers utilized a vulnerability on the popular video conferencing platform which allowed them to remotely control PCs. These vulnerabilities were reportedly being sold online for $500,000.
  • Apple in 2020: Hackers were compromising devices from remote locations due to a bug in Apple’s iOS software. In order to avoid these future exploits, Apple has offered to pay $2 million to any person that finds a vulnerability in iOS.
  • Microsoft Windows in 2019: Microsoft Windows software was exploited for government agencies across Eastern Europe. This resulted in suspicious apps being installed, as well as data being changed, and programs being compromised. 

Final Thoughts

Zero-day phishing attacks are not going away any time soon. As the world continues to become increasingly digital, companies large and small need to be prepared to protect their organizations and employees from fraud. 

Ready to learn more about how you can protect your business from zero-day phishing attacks? Get a demo with the Cyren team today.


Apr 25, 2022 | Phishing

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