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9 Types of Malware Explained

9 Types of Malware
9 Types of Malware

In our mission to raise awareness about the dangers of cybercrime. We thought we would have a brief walkthrough of the different types of Malware there are.

Aside from corrupting your hardware and putting your information at risk. It’s worth knowing what different types of Malware exist, and what they can potentially do to your system.

What is Malware?

Malware is software aiming to disrupt and damage a computer system. Obtaining unauthorised access to a user’s account conflicts with the device or machine.

Malware can express various traits; using up processing power, restricting internet connection and controlling installed programs.

Types of Malware

There are 9 different types of Malware. These are Bugs, Viruses, Trojans, Adware, Bots and Botnets, Ransomware, Worms, Spyware, and Rootkits.


A type of error, flaw or mistake that produces an unwanted or unexpected result. Typically, bugs exist in a website’s source code and can cause a wide range of damage.


Without a user realising, a piece of code is loaded onto the user’s website, device or machine. The virus then easily multiplies and transfers via a file attachment.

  • Definition: A virus is malicious software that attaches to clean files and spreads throughout a computer system.
  • Mode of Operation: It relies on human activity to propagate, requiring users to open a file or run a program to activate it.
  • Impact: Viruses can delete files, corrupt your hard drive, or use your computer to spread to other computers.
  • Examples: CIH (or Chernobyl Virus), Sasser.


Just like the famous Trojan horse narrative, Trojan viruses take the same inspiration. Disguising themselves as a normal or familiar file, they trick the user into downloading it.

  • Definition: Trojans are malicious programs that mislead users of their true intent.
  • Mode of Operation: They disguise themselves as legitimate software but deliver a malicious payload when executed.
  • Impact: They can provide backdoor access to attackers, leading to data theft or control over the compromised system.
  • Examples: Emotet, ZeuS.
Trojan Malware
Trojan Malware


Adware automatically shows multiple unwanted advertisements. When the advertisement is shown, it encourages the user to click it and be redirected to a malicious site or download a dangerous file.

  • Definition: Adware is unwanted software designed to show you advertisements.
  • Mode of Operation: Often bundled with freeware and shareware.
  • Impact: While not always malicious in intent, it can degrade system performance and be annoying. Some might also track your browsing habits.
  • Examples: BrowseFox, Adposhel.

Bots and Botnets

A software program created to perform or execute a specific task. Bots are typically used for DDoS attacks. Where they try and bring down a website by overloading the server.

  • Definition: Bots are automated processes designed to infect a device, while Botnets are networks of hijacked computers.
  • Mode of Operation: Bots can perform automated tasks over the Internet. When malicious, they can be used for a variety of nefarious activities. Botnets can be used for large-scale attacks or spam campaigns.
  • Impact: They can lead to Distributed Denial of Service (DDoS) attacks, spam email campaigns, and more.
  • Examples: Mirai, Zeus (as a botnet).


Ransomware denies access to your files and demands payment to regain control. A regular scenario ends with the payment being delivered in Bitcoin as the transaction is instant.

  • Definition: Ransomware is malware that encrypts a victim’s files and then demands payment in exchange for the decryption key.
  • Mode of Operation: Often spreads through phishing emails or malicious downloads.
  • Impact: Can lock out users from all files, leading to data loss if not paid.
  • Examples: WannaCry, CryptoLocker.
Ransomware Malware
Ransomware Malware


A worm is a type of malware that exposes a security flaw or failure. It then copies this and then spreads itself to another computer. It then consumes bandwidth to overload a server.

  • Definition: A worm is a standalone software replicating itself to spread to other computers.
  • Mode of Operation: Unlike viruses, worms don’t need human intervention to propagate. They can exploit vulnerabilities in software to spread.
  • Impact: They can consume bandwidth or overload web servers, leading to Denial of Service (DoS) attacks.
  • Examples: Conficker, SQL Slammer.
Worms Malware
Worms Malware


Spyware is a type of malware that functions by spying on a user’s activity. This type of spying includes monitoring a user’s activity. Meaning it could even monitor your keystrokes.

  • Definition: Spyware is malware designed to spy on users, gathering information without their knowledge.
  • Mode of Operation: Can be installed on a system via deceptive links, websites, or packaged with other software.
  • Impact: It can lead to privacy breaches, identity theft, and financial loss.
  • Examples: CoolWebSearch, Zlob.


  • Definition: A rootkit is a collection of software tools that enable unauthorized access to a computer or area of its software.
  • Mode of Operation: They are designed to be hidden and can even camouflage their activities.
  • Impact: Rootkits can modify system configurations and might even alter software, especially any software that might detect its presence.
  • Examples: ZeroAccess, Necurs.

How Malware Spreads

Malware can spread like wildfire. It can come from malicious websites, email attachments, or legitimate software downloads.

Phishing Emails

One of the most common ways malware spreads is through deceptive emails. Attackers craft legitimate-looking emails, enticing users to click on a link or download an attachment.

For instance, the email might claim you’ve won a prize or there’s an important invoice you need to check. Once clicked or downloaded, the malware activates, so it’s best practice to follow procedures when dealing with a fake email.

Software Vulnerabilities

Outdated software or systems that haven’t been patched can have vulnerabilities that hackers exploit to inject malware.

Social Engineering

This involves manipulating users into breaking security protocols, like giving away passwords or accessing a restricted area. Social engineer can be done by hackers through multiple methods. Examples of social engineering is a place of work uploading too much information about a worker, or utilising social media. These are just two ways hackers can social engineer, and finding information about you can help hackers into your accounts. Once inside, attackers can introduce malware.

Social Engineering
Social Engineering

How to Protect against Malware

Regular Updates

Updating your software is like getting a flu shot. It helps protect against known vulnerabilities.

Security Software

For businesses, adding in an additional layer of protection software can drastically reduce the amount of spam and phishing emails. If you’d like to learn more about this, submit a form below and our cyber security experts will be in touch shortly.

Cyber Security Education

Understanding where risks come from is a vital part of reducing the chances of being infected with malware. Our cyber security training is a short, interactive course to help employees understand the basics of cyber security from as little as £2 per user, per month.

Next steps?

Excellence IT is a Managed-Service Provider, providing IT Support based in Cardiff and surrounding areas. If you have any other questions about viruses and how they can affect your business, then please get in contact with us by submitting a form below.

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