Malware: Definition, Types, and Detection 101

by | June 24, 2021 | Cybersecurity, How to

Malware is designed to harm infected devices and networks, used for various sorts of theft, causing a significant amount of damage in terms of finances. Keep reading to find out what it implies, how it spreads and works, what are the most common types and how to detect an infection of this sort.

What does Malware mean?

Malware” is the short form of the term ”malicious software” and sums up all programs or files designed to cause harm intentionally or to exploit devices, networks, or services. Attackers use it for crimes such as stealing sensitive data, monitoring users’ activity, compromising or deleting information from the device. The stolen information can vary from emails, financial and healthcare data, passwords – nowadays, possibilities are endless regarding the kind of information attackers can compromise or steal. Cybercriminals use the illegally obtained data against their victims for financial gain.

”Malware” is the short form of the term ”malicious software” and sums up all programs or files designed to cause harm intentionally or to exploit devices, networks, or services

How does Malware spread and work?

Hackers use various means, both virtual and physical, to spread malware. Virtual ways of spreading include text messages, fake software installations, malicious advertising, phishing emails, which contain an URL that leads unsuspecting victims to download infected apps on their devices, or even an attachment with a malicious executable file. The most common physical mean of spreading are infected USBs.

Once a device, a system, or a network has been compromised by malicious software, it will often attack using a command-and-control server, which allows threat actors to communicate with the infected systems, obtain sensitive information, and remotely control the affected devices or servers.

Malware may use evasion and obfuscation strategies to hide from users and even antimalware products. More complex attacks use polymorphic malware that can constantly change its code to avoid detection based on its signature.

Sometimes, the effect malware has might be mild and apparently benign, but often it can be disastrous, especially for companies and businesses.

What are the most common types of malware?

There are many types of malware, but here are the most common ones:


A virus is the most common type, usually delivered as an attachment in an email. If the user opens the attachment, the device gets infected. It executes itself compromises files or programs.


It`s one of the most profitable and popular types of malicious software. It installs on its own onto the victim`s device, encrypting their files, and then requests payment in exchange for returning the data to the user.


Spyware is designed and intended to gather information on the device and its users and monitor their activity against their knowledge. It is used by government, law enforcement, and information security institutions, but is also available to consumers, allowing them to spy on other people.


Adware is used to monitor the browsing and downloading history of the victims and push unwanted ads at them. These pop-ups and banners lure the user into making a purchase.


A worm copies itself from device to device by exploiting security vulnerabilities in an operating system or software without requiring any form of user interaction.


Trojan horses present themselves as harmless legitimate software programs to trick users into downloading and installing them. When installed, a trojan can exfiltrate sensitive data, crash the machine, spy, or execute an attack.


Attackers scare the victims into believing their devices are infected to persuade them to purchase a fake app. Alarming messages such as ”Warning, your device is infected!” or ”You have a virus!” appear when browsing the Internet in the case of a typical scareware scam.

Fileless malware

It uses legitimate software to infect a device. This kind of attack leaves no traces of malware files or malicious processes, making it particularly difficult to detect and remove.

How can you detect Malware?

Here is a list of the most common indicators that your device has been infacted by malware:

  1. Your computer’s performance is slower than usual;
  2. You often get infection warnings, usually accompanied by requirements to buy a product to resolve the issue;
  3. The browser redirects you to sites you did not intend to access;
  4. You encounter difficulties when turning on or shutting down your computer;
  5. You frequently get intrusive pop-up ads asking you to purchase something.

The more of these common signs you observe, the higher the probability of your device being compromised by malware. The best ways to prevent the infection from happening are choosing trustworthy antivirus software and implementing Cybersecurity training programs, especially for companies.


Computer vector created by vectorjuice –

by Diana Panduru

Content writer for Attack Simulator. Passionate about all things writing and cybersecurity, and obsessed with driving. I sometimes indulge in pencil drawing, poetry, and cooking for fun.

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