10 Different Types of Malware

Presenting some of the most significant dangers one could encounter on the internet today, malicious software is generally utilized by cybercriminals in order to gain illegal access to any of your devices, with the clear intention to damage the available data or even harm people in a number of ways.

But even though terms such as “malware”, “bugs” and “viruses” are often used quite loosely in jargon nowadays, malicious software can come in a number of different forms, all of which are vital to know and recognize, in an effort to keep yourself safe online, as well as any professional systems you might have.

To that end, here are some explanations of what exactly malware represents, the different forms of malicious software that currently exist, and some ways you could avoid becoming the victim of future cyber attacks:

What exactly does malware represent?

The word “malware” itself represents a shortened version of the phrase “malicious software”. Essentially, it is used as an umbrella term that incorporates any form of malicious code that presents a potential danger.

Although the specific definition for malware could vary, it is generally described as any type of file, application, program, or another form of software that could be utilized in order to gain illegal access to computers and networks, with the clear purpose of sabotage, extortion, espionage, or even theft.

In more practical terms, this means that malware actually has the potential to harm you in a number of different ways, from personal damage to stolen information and funds, in case you aren’t properly protected.

Nowadays, malware most commonly infiltrates devices or networks through phishing attacks (mostly through emails and social media messages), as well as malicious downloads and attachments, although it could be introduced with flash drives or social engineering as well.

The most frequent types of malware

Once you completely understand what malicious software represents, as well as ways it could infiltrate your system, it’s now time to dive more deeply into the subject.

Considering the fact that this catch-all terminology can be extremely broad, it’s vital to get familiar with the many different malware varieties that currently exist, and how they could impact your devices and networks. With that in mind, here is a list of the most frequent types of malware you might encounter:

1. Viruses

Even though many individuals tend to label all malware as viruses, that is certainly not the case. Computer viruses are only one specific malware variety that is often attached to documents or executable files, which tends to modify other valid files within the system, thus spreading the virus even further.

When an infected file, attachment, or program is downloaded onto a device, the virus will most likely remain inactive until the infected file in question is executed, ultimately activating the computer virus at the same time as well. And considering the fact that these viruses spread quite quickly, even to host files, many antivirus software will find it extremely difficult to completely remove a virus from a computer.

Thankfully, computer viruses have become much rarer today, representing less than 10% of malicious software that can be found on devices.

2. Worms

As opposed to viruses, worms don’t generally demand any action to be performed by the user in order to be activated. Worms are notorious for having the ability to reproduce themselves, expanding themselves automatically in the process, and thus slowly infecting the entire device, or even the whole network in certain instances. Unfortunately, this self-regulating nature is exactly what makes them so efficient.

Once a specific device or an entire network is infected with a worm, this malware can do quite serious damage, such as injecting other malware, modifying or deleting existing files, stealing available data, and even installing a backdoor for potential hackers.

3. Trojan Horses

Another form of malware that has existed for a long while, Trojan Horses have quite an appropriate name. They often disguise themselves as legitimate files and programs, even though they represent malicious software. This seemingly trustworthy nature prompts users to download and execute Trojan files, thus unwittingly infecting their devices.

Trojan Horses tend to arrive at a user through emails, or even through advertisements on already infected websites. Fake antivirus software and fake excel or word documents tend to be the most common forms.

Nowadays, Remote Access Trojans (RATs) have become particularly popular among attackers, as they allow cybercriminals to gain remote access to a victim’s device, most likely in an effort to infect their entire network. These forms of malicious software can be particularly harmful, as they’re quite simple to write or buy, but difficult to detect on a computer.

4. Bots and Botnets

A bot represents a computer that has been infected with malicious software, thus allowing attackers to remotely access and control it. This bot (often referred to as a zombie computer) could then be utilized for executing even more attacks, or in an effort to create a botnet (or a group of bots).

Botnets have now become incredibly popular among hackers, mostly when it comes to spreading different forms of ransomware or performing DDoS attacks.

5. Ransomware

Much like its name already suggests, ransomware is another variation of malware that encrypts your information and blocks you from accessing it until you provide a payment (usually in the form of a cryptocurrency). Essentially, this malware holds your information hostage until you pay a ransom.

As ransomware attacks tend to revolve around the theft of data or other types of intellectual property, they most commonly affect private companies, institutions such as police departments and hospitals, as well as entire cities.

A large percentage of ransomware programs are also Trojans, meaning they tend to spread via social engineering and phishing, also requiring users to execute files in order to infect their devices. However, while some ransomware will infect systems instantly, others have a more intentional, delayed approach, making them even harder to spot.

6. Adware

Among the most well-known malware varieties, adware usually exposes end-users to unwelcome, intrusive advertisements, mostly in the form of pop-ups or internet browser ads. This malware variety is generally disguised as valid software, or even incorporated into another file, in an effort to trick the user into installing it onto their device.

Even though adware is seemingly among the least harmful forms of malicious software, it’s becoming increasingly common, and could potentially expose any infected users to other, more dangerous forms of malware, making them even more susceptible to potential cyber-attacks.

7. Spyware

Another malware type that’s quite evident from the name itself, spyware is generally used for gathering information, whether about a person or an organization. This form of malware can monitor online activity, but also collect any personal data, such as passwords, payment details, or other forms of intellectual property.

Although spyware tends to be most commonly used by individuals who’d like to monitor people close to them, this malicious software could also be utilized by cybercriminals during targeted attacks, in an effort to collect private and sensitive information, which they could then sell for a considerable profit.

And while spyware is among those malware options that are quite uncomplicated to locate and remove from a device, the mere presence of any spyware on a personal device should represent a serious warning that the safety and security of the individual have certain weaknesses that must be addressed, particularly when it comes to businesses and institutions.

8. Rootkits

Rootkits represent certain malware clusters that were specifically designed for giving illegal access to a device or an aspect of its already installed software. The installation procedure for rootkits can either be automatic, or the cybercriminal could install it using administrative access, but it’s generally quite efficient at hiding its own existence or disguising other forms of software.

In most cases, rootkits gain illegal access to a certain device via direct system attacks like phishing, exposed passwords, or exploited vulnerabilities. However, the detection of rootkits can be incredibly challenging, as it tends to overturn the antivirus which is supposed to locate it. What’s more, the complete removal of this malware can often turn out to be nearly impossible.

9. Fileless malware

Although file-less malware isn’t technically a different category of malicious software, it is generally exploited in a more unique manner. While more traditional malware varieties tend to infect computers and travel through system files, fileless malware actually expands only through memory, utilizing “non-file” system objects such as registry keys, APIs, and scheduled tasks.

Representing over half of all malicious software today, fileless malware tends to exploit valid programs or tools that already exist within the OS. For this very reason, fileless malware can be particularly demanding to identify and stop on any device.

10. Hybrid malware

Most malicious software nowadays tends to be a mixture of the aforementioned malware varieties, most commonly Trojan Horses, worms, and sometimes even viruses. Such malware tends to look just like a Trojan Horse to any user, but it could then perform attacks on other network users (just like a worm) once executed.

A large number of the hybrid malware forms found today act similarly to rootkits, modifying the OS in an effort to take over control, and escape detection from antivirus programs. That is why they can often be hard to locate and remove.

How to know if you’ve been infected

While some forms of malicious software could be particularly challenging to detect, there are certain warning signs that might signal the presence of potential malware varieties on your computer. Here are some of the most frequent signals:

  • A device that is especially slow, or often freezing and crashing.
  • Inexplicable lack of storage space on your device.
  • A sudden increase in pop-ups on your computer, or trusted software closing and opening for no apparent reason.
  • Received messages and emails without any previous prompting.
  • BSOD, also known as the blue screen of death.

How you could protect yourself from malicious software

Even though 100% protection from malware can never be guaranteed, there are some basic steps you could take in an effort to keep your devices safe and turn yourself into a more difficult target for potential attacks. Here are some things you should do:

  • Maintain your operating systems, programs, browsers, and all other software regularly updated.
  • Use efficient antivirus software on all your devices and any other necessary security tools.
  • Make sure to set quite strong and unique passwords for all your accounts, and never store them on the devices themselves.
  • Limit the access to all your accounts only to those individuals who could be trusted, and who truly have to use them.
  • Make an effort to browse the web safely, such as visiting only legitimate websites, not clicking on suspicious links and ads, and being mindful of potential social engineering attacks.
  • Avoid using public internet connections that aren’t encrypted or protected in any other way.
  • Aim to put additional layers on your personal security, like using firewalls, specific malware detection tools, or putting filters and additional security protocols on emails.


Evidently, cybercriminals have a wide array of different tools and techniques they use in order to compromise and extort systems, as well as their users. And unfortunately, it seems like malware is only rising in popularity, with criminals constantly finding new tactics for performing attacks, ultimately presenting arguably the biggest threat to both individuals and institutions on the internet today.

For this very reason, it’s vital for you to improve your security efforts and ensure your defenses are as strong as they could possibly be. While you could never fully protect yourself from malware attacks, you could always make an effort to deter cybercriminals by being a difficult target unworthy of attacks.