Malware or viruses can be missed by the antivirus protection software for several reasons. Find out more below and learn what to do if you suspect undetected malware or a virus, even if you have a cyber security solution in place.


Can virus or malware go undetected?

Malware or viruses can be missed by software for several reasons. One reason is that the software may not be able to recognize the malware or virus because it is new and has not been previously identified. Another reason is that the malware or virus may be designed to evade detection by disguising itself or hiding in legitimate files. Additionally, the software may not be updated regularly, which can leave it vulnerable to new malware or viruses. Finally, the software may not be designed to detect certain types of malware or viruses.

Read this in-depth guide to learn more about:

  • Why malware can go undetected
  • How to tell if you have undetected malware or viruses
  • What do to if you caught a malware through a virus scan
  • How to protect yourself from malware in the future

Here’s a proof that many software solutions miss malware and viruses: we caught these threats on machines that have antivirus protection installed: 

Undetected Malware Map – See what our competitors missed:

undetected malware map

It’s important to note that no antivirus software can guarantee 100% protection against all viruses, so it’s important to have a multi-layered security approach, keeping the software and the operating system updated, and avoiding risky behavior such as downloading files from untrusted sources or clicking on suspicious links.

Malware is an umbrella term for any program that tries to invade or harm a system. It includes viruses, worms, Trojans, adware, ransomware, and others. Today’s malware is smarter, carrying new evasion techniques and mechanisms to stay hidden and carry out its functions unhindered. If you want to learn more about computer viruses and malware, you could check these more in-depth articles: What is Malware? and What is Computer Virus?

What happens if malware goes undetected?

So, what if your antivirus software does not detect hidden malware? Whether you’re a home user or an organization, the ramifications can range from mildly annoying to very serious:

Here are some possible consequences, if your anti-malware software does not detect and remove a virus or other malware threats.

  1. Performance issues: Some types of malware can force your hardware to slow down, overheat, or stop functioning. Others, like adware, may throw up pop-ups that interrupt your workflow.

  2. Data corruption: PC viruses, worms, some Trojans, and ransomware can corrupt your data.

  3. Identity theft: Spyware, stalkerware, keyloggers, and some Trojans may help facilitate identity theft.

  4. Financial crimes: The same kind of malicious software that allows threat actors to steal your identity can also aid them in financial crimes.

  5. Extortion: Extortionists infamously use ransomware to hijack systems for ransom. They can also utilize some types of spyware for blackmail.

  6. Lateral movements: Some malware that goes undetected can allow cybercriminals to dig deeper into your organization’s network to snoop on your sensitive assets or launch a more advanced attack.

  7. Supply chain attack: Internal or external threat actors may use hidden malware to harm partners in your business relationships in a supply-chain attack.

Reasons antivirus software fails

Is it possible that your antivirus or anti-malware can miss viruses and other malware hidden in your computer? It is possible, just check this map of undetected viruses and malware for computers that have protection in place.

There are a few reasons for undetected malware:

  • Volume: Although the exact number is undecided, researchers find hundreds of thousands of new malicious programs every day. The sheer volume of malicious programs means that some of the newest ones can slip through the cracks and bypass common cybersecurity measures.

  • Out-of-date antivirus software: Legacy antivirus programs that block malicious programs by detecting signatures rely on an updated database to stop the latest known threats.

  • Obsolete antivirus software: Antivirus tools that rely solely on signature-detection technology may fail to block emerging threats with unregistered signatures. We recommend that you download advanced antivirus software that uses signature-detection and behavior-recognition mechanisms. Emerging threats with unknown signatures can be stopped by anti-malware tools that utilize Artificial Intelligence and Machine Learning to detect threatening patterns in new threats.

  • Undetectable malware: Some malware can be challenging to detect due to its sophisticated design, allowing it to bypass cybersecurity mechanisms. For example, some malware may be specifically designed to trick a popular antivirus software into believing it’s harmless. Other malware may use social engineering to trick you into installing it.

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Signs you have undetected malware

There are several signs that you may have malware on your computer, including:

  • Unusual pop-up ads or browser redirects: Malware can cause pop-up ads or browser redirects to appear on your computer, even when you’re not browsing the web.

  • Slow performance: Malware can slow down your computer by consuming resources and causing conflicts with other programs.

  • New programs or files: Malware can install new programs or files without your knowledge.

  • Modification of settings: Malware can change settings on your computer, such as your homepage or default search engine, without your knowledge.

  • Unusual network activity: Malware can cause unusual network activity, such as increased data usage or connections to unfamiliar IP addresses.

  • Unexpected error messages or crashes: Malware can cause your computer to display unexpected error messages or crash frequently.

  • Your personal files or sensitive information is missing or modified.

It’s important to note that some of these signs may also indicate other problems, not necessarily malware infection, so it’s important to run a malware scan to confirm if your computer is infected.

If you suspect a virus or malware on your phone, check out this article: how to remove a virus from your iPhone.

What to do if you suspect undetected malware?

If you suspect that your system has a malware infection, the first thing you should do is run a virus scan

If the scan identifies malware, follow these malware removal steps:

  1. Use a free malware removal tool: There are several free malware removal tools available online. These tools are specifically designed to remove malware and may be more effective than a traditional antivirus program.

  2. Run a system restore: If the malware has caused changes to your system settings or files, you can use the built-in System Restore feature to restore your computer to a previous state.

  3. Manually remove the malware: If you are familiar with the operating system and the file structure, you can manually remove the malware by deleting the malicious files and registry entries.

  4. Disconnect from the Internet: If you suspect that you have malware, it’s best to disconnect your computer from the Internet to prevent the malware from spreading or communicating with its command and control center.

How to protect yourself from undetectable malware and viruses

There are several steps you can take to protect yourself from undetectable viruses and malware:

  1. Keep your operating system and software updated: Software updates often include security patches that can protect against new and emerging threats.

  2. Use a reputable antivirus or anti-malware program: Make sure to use a reputable antivirus or anti-malware program and keep it updated. This will help to detect and remove known malware.

  3. Use a firewall: A firewall can help to block unauthorized access to your computer and can help to prevent malware from communicating with its command and control center.

  4. Be cautious when opening email attachments or clicking on links: Malware can often be spread through email attachments or links, so be sure to only open attachments or click on links from trusted sources.

  5. Use a VPN: A Virtual Private Network (VPN) can help to encrypt your internet connection and can protect your personal information from being intercepted by malicious actors.

  6. Practice safe browsing: Be careful when visiting unfamiliar websites and avoid downloading files from untrusted sources.

  7. Use multi-layered security approach: Having a multi-layered security approach such as using a combination of antivirus, anti-malware, firewall, VPN, intrusion detection and prevention system, and so on can provide better protection against malware and viruses.

  8. Back up your data: Regularly back up your data to an external drive or cloud storage to prevent loss of important files in case of malware infection.

By following these steps, you can help to protect yourself from undetectable viruses and malware.


What does malware mean?

Malware, or malicious software, is a term for any kind of computer software with malicious intent. Most online threats are some form of malware. Malware can take many forms, including viruses, worms, trojan horses, ransomware, and spyware.

Can malware be undetected?

Yes, malware can hide itself and antivirus and other protection programs may not catch it. Check out this undetected malware map

What are the signs of malware?

You have weird pop-ups, your device is slower than usual, battery dies too soon and device is overheating - can be all signs of malware. 

How to remove malware?

If you performed a malware scan and found malware on your device, you can remove it with a proper anti-malware in place, such as Malwarebytes software.