---
title: What is Malware?
description: Malware is malicious software used to disable or damage computers. Learn more about malware.
image: https://www.cloudflare.com/preview.png
---

##  What is malware? 

 Malware is software that is designed to disrupt normal operations of a device. 

######  Learning objectives 

 After reading this article you will be able to: 

* Define malware
* Explore and differentiate between common malware attacks
* Understand potential risks for malware attacks, and how to reduce vulnerability

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On this page 

## What is malware?

 Malware, a portmanteau from the words "malicious" and "software," is a general term which can refer to viruses, worms, Trojans, [ransomware](/learning/security/ransomware/what-is-ransomware/), spyware, adware, and other types of harmful software. A key distinction of malware is that it needs to be intentionally malicious; any software that unintentionally causes harm is not considered to be malware.

 The general goal of malware is to disrupt the normal operations of a device. This disruption can range in purpose from displaying ads on a device without consent to gaining root access of a computer. Malware may attempt to obfuscate itself from the user in order to collect information quietly or it may lock the system and hold data for ransom. In [DDoS attacks](/learning/ddos/what-is-a-ddos-attack/), malware such as [Mirai](/learning/ddos/glossary/mirai-botnet/) affects vulnerable devices, turning them into [bots](/learning/bots/what-is-a-bot/) under the control of the attacker. Once modified, these devices can then be used to carry out DDoS attacks as part of a [botnet](/learning/ddos/what-is-a-ddos-botnet/).

The creation of malware arose as the result of experiments and pranks by computer programmers, but discovery of the commercial potential it creates has turned malware development into a lucrative black market industry. Today, many attackers offer to create malware or launch malware attacks in return for compensation.

## What are some common types of malware?

* **Spyware** \- As the name implies, spyware is used to spy on a user’s behavior. Spyware can be used monitor a user’s web browsing activity, display unwanted ads to the user, and modify affiliate marketing streams. Some spyware uses what’s called a keylogger to record the user’s keystrokes, giving the attacker access to sensitive information including usernames and passwords.
* **Viruses** \- A virus is a malicious program that can be embedded in an operating system or a piece of software; the victim needs to run the operating system or open the infected file to be affected.
* **Worms** \- Unlike viruses, worms self-replicate and transmit themselves over a network. The user does not have to run any software to become a victim; just being connected to the infected network is enough.
* **Trojan Horses** \- These are pieces of malware that come hidden inside other useful software to entice the user to install them. Pirated copies of popular software are often infected with trojan horses.
* **Rootkits** \- These software packages are designed to modify an operating system so that unwanted installations are hidden from the user. A famous example is the 2005 Sony rootkit scandal, when Sony sold 22 million music CDs that came infected with a rootkit that would secretly install software intended to disrupt CD-copying on the purchaser’s computer. This rootkit opened up the door for other attackers to target infected computers with additional malware.
* **Ransomware** \- This software can encrypt files or even an entire operating system on a computer or network and keep them encrypted until a ransom is paid to the attacker. The emergence of bitcoin and other [cryptocurrency](/learning/ddos/cryptocurrency-ddos-attacks/) has created a surge in the popularity of ransomware attacks, as attackers can anonymously accept currency and minimize the risk of getting caught.

## What are the risk factors for malware infection?

* **Security bugs** \- Software such as operating systems, web browsers, and browser plugins can contain vulnerabilities for attackers to exploit.
* **User error** \- Users opening software from unknown sources or booting their computers from untrusted hardware can create a serious risk.
* **OS sharing** \- The use of a single operating system by every computer on a network also increases malware infection risk; if all the machines are on the same OS, then it is possible for one worm to infect them all.

## How can you stop malware?

 No one can be completely impervious to malware attacks; new attacks are constantly being developed to challenge even the most secure systems. But there are plenty of ways to minimize vulnerability to malware attacks. These include:

* **Anti-virus and anti-malware software** \- Running regular scans on a computer or network is crucial to detecting threats before they can spread.
* **Website security scans** \- People who have websites should be aware that malware can target a website’s software to view private files, hijack the site, and potentially even harm that site’s visitors with forced malware downloads. Running regular security scans on a website can help to catch these threats.
* **Web Application Firewall (WAF)** \- Another good resource for webmasters is a [WAF](/learning/ddos/glossary/web-application-firewall-waf/), which can block malware at the [edge of a network](/learning/serverless/glossary/what-is-edge-computing/) and prevent it from reaching a site’s [origin server](/learning/cdn/glossary/origin-server/).
* **Air gap isolation** \- Considered to be a last resort, air gap isolation means cutting a computer or network off from all outside networks and Internet communication by disabling any hardware that would make communications possible. Even this is not a foolproof defense and has been compromised by tactics such as the ‘dropped drive’ attack, where USB drives are dropped in a company’s parking lot in hopes that a curious employee will find one and plug it into a computer on the network, infecting the isolated network with malware.

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