Zero-Day Exploits Have Reached a Record High in 2021 – How to Prevent These Attacks

A zero-day exploit has become the rising star in the cybercrime landscape, giving IT security staff sleepless nights. It was once a privileged cyberweapon levelling only elite government hackers’ playfield. Today, zero-day attacks have reached record highs targeting Microsoft servers or Google Chrome browsers, among others.

Anyone is a potential victim of a zero-day attack. Let’s see how these attacks unravel and what you can do to avoid them.

What’s a Zero-Day Attack?

One of the sneakiest cyber tricks, a zero-day attack aims to destroy vulnerable systems before developers or creators of that system get a chance to fix it. In essence, there are zero days available to patch the vulnerability since it was just recently exposed. Developers can pinpoint the vulnerability that led to the attack in days, weeks, or even months.

A zero-day exploit negatively impacts the hardware, applications, data, or an entire network, like:

      • Operating systems
      • Web browsers
      • Office applications
      • Open-source components
      • Hardware and firmware
      • Internet of Things (IoT)

Here is how this type of attack emerges:

  1. companies officially release software they believe to be flawless, aka with no vulnerabilities;
  2. attackers do their work looking and spotting a vulnerability;
  3. attackers create the exploit code and launch it either through a virus, malware or a phishing email.

It’s All About the Money

A successful zero-day attack leads to identity theft or stealing company or personal confidential data. Cybercriminals can sell data captured from an exploit attack on the dark web for large sums of money. In worse cases, some recent zero-day exploits have proven to be the forewarning of a ransomware attack.

Based on recent estimates, financially motivated actors orchestrate one-third of zero-day exploits.

zero day attacks rise 2021

Recent Zero-Day Exploits

A Zero-Day Bug from Palo Alto Networks

After a year since their initial discovery of the flaw, Randori security firm disclosed a critical vulnerability within a service from Palo Alto Networks (PAN).

The vulnerability could leave 10,000 vulnerable firewalls with users’ secured network items exposed to the internet. Attackers could access sensitive configuration data, capture system and account credentials and more. Many of the Fortune 500 companies and other multinational organizations use Palo Alto Network’s security appliance.

The company has stated they patched the vulnerability and that there’s no sign of data leaks or other exploits. Still, the company’s decision to reveal the vulnerability after 12 months has raised several question marks. Palo Alto Networks explained they chose to use this zero-day exploit as part of the company’s red team (employees responsible for assessing security incidents) exercise.

macOS Exploit Targeting Hong Kong Users

Google’s Threat Analysis Group (TAG) reported they caught attackers exploiting unknown vulnerabilities in Apple’s Mac operating system. The exploit was targeting users in Hong Kong, and according to researchers, their tactics carry the signature of government-backed attackers.

The bad actors hid malware within legitimate websites of a media outlet in Hong Kong. A zero-day vulnerability would hit users visiting these websites via a previous macOS vulnerability used to create a backdoor on computers. Yet, the exploit targeted iOS devices as well, but security researchers only managed to restore macOS devices.

So far, based on the software code containing Chinese strings, security experts suggest either Chinese attackers or perpetrators posing as Chinese were behind this attack.

And the good news is Apple patched this zero-day exploit.

A New Zero-Day Impacts all Windows Versions

A Windows zero-day vulnerability gives SYSTEM privileges to threat actors with the condition they know user names and passwords. Due to this condition, it was assumed the bug wasn’t such a serious threat. The only downside was it could affect all versions of Windows, including Windows 10, Windows 11, and Windows Server 2022.

As part of the exploit, an attacker can create a shortcut link to a file or folder in the User Profile Service; the code used for creating this link would create a folder that contains a malicious library.

Microsoft originally disclosed the bug in August and soon mentioned it managed to patch it. After a few months, though, a security researcher found that the patch was ineffective as he was able to go past it.

How to Protect Yourself Against Zero-Day Attacks

Regardless that statistically, the number of zero-day attacks has increased, cybersecurity experts believe these exploits have just turned out easier to identify. In other words, ethical hackers have started to know more about them now compared to last year, for example.

Even so, with zero-day attacks, prevention is essential since they’re fairly unpredictable. Check these easy-to-follow cyber security habits to stay away from this kind of exploit as far as possible:

Always keep your software and operating system updated

By not allowing yourself to skip any software update, your data and device are more secure; in most cases, security patches cover the latest identified vulnerabilities, so you stop unwanted events like threat actors creating a backdoor into your system.

Use only essential applications

This might sound like old-fashioned advice, but it follows this logic: the more software and apps, the greater the risk; that’s why you should settle for downloading and using strictly necessary apps.

Update your browser

Zero-day attackers like to target browsers too; most browser updates are automatic but double-check once in a while because you leave your browser exposed to vulnerabilities if not updated.

Use a firewall

Like a guardian of a castle, a firewall is your first and primary line of defense against unwanted guests. Firewalls can ensure maximum protection. Find out more about types of firewalls and tips on how to configure them.

Get CyberGhost VPN Security Suite

Our security suite includes Intego antivirus and Security Updater: benefit from real-time automatic scanning of the latest updates to make sure you’re protected against the newest threats, including zero-day attacks.


Have you ever been affected in any way by a zero-day exploit?

Let me know in the comments section below.

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