1 Introduction
Malware is like a digital disease. Just as biological viruses infect the human body, malware infects computers and networks. The word "malware" comes from "malicious software." It is an umbrella term for all programs designed to cause harm: stealing data, locking systems, spying on users, or taking control of machines.
560,000+
New malware samples detected every day
7 types
Major malware families
$20B+
Annual cost of ransomware worldwide
2 How It Works
The family tree below shows the major malware families. Each branch represents a different type, with its own characteristics and method of attack.
Virus
Spreads by attaching itself to other files. Like a biological virus, it needs a host to reproduce.
Worm
Spreads on its own across networks without human interaction. Can infect thousands of machines in hours.
Trojan
Disguises itself as legitimate software to trick the user. Once installed, it opens a backdoor for attackers.
Ransomware
Encrypts your files and demands a ransom to unlock them. The most feared type of malware for businesses.
Spyware
Silently monitors your activity: keystrokes, websites visited, screenshots. You do not even know it is there.
Adware
Displays unwanted advertisements. Less dangerous, but often bundled with spyware or malicious redirects.
Rootkit
Hides deep inside the operating system. Extremely hard to detect, it gives the attacker total and persistent access.
3 Detailed Analysis
How malware spreads
Email attachments
The number one vector. A Word document with a macro, a booby-trapped PDF, a ZIP file containing an executable. One click is enough.
Compromised websites
Legitimate sites that have been hacked to distribute malware to visitors, or fake sites mimicking well-known services.
Pirated software and cracks
Downloading "free" software or a crack is one of the most common ways to catch a Trojan horse.
USB drives and peripherals
Plugging in an unknown USB drive can trigger automatic malware execution. This is how Stuxnet spread.
Famous examples
WannaCry (2017)
Ransomware that infected 230,000 machines across 150 countries in hours. Paralyzed hospitals, factories, and government agencies. Exploited a Windows vulnerability known as EternalBlue.
Emotet (2014-2021)
Started as a banking Trojan, evolved into a malware distribution platform. Spread via email by replying to real stolen conversation threads. Dismantled by Europol in 2021.
Try it on mlab.sh
Upload a suspicious file to scan it against multiple detection engines. Get a detailed analysis report with verdicts, detection names, and behavioral indicators.
Scan a file on mlab.sh4 Red Flags
Computer suddenly slows down
If your machine becomes very slow for no reason, malware may be using your resources (cryptocurrency mining, sending spam...).
Unknown programs launch at startup
Regularly check which programs start automatically. An unknown or random-looking name is a sign of infection.
Unusual pop-ups and redirects
Ad windows appear even when your browser is closed, or you are redirected to sites you did not request.
Antivirus mysteriously disabled
Some malware disables security software as a first priority. If your antivirus turns itself off, that is a serious warning sign.
Files renamed or inaccessible
Files with strange extensions (.encrypted, .locked, .crypt) or a message asking you to pay? That is ransomware. Never pay the ransom.
Related Modules
Source: mlab Academy — Cybersecurity Awareness Platform
URL: https://academy.mlab.sh//page/malware
Module: What is malware? — Fundamentals
Disclaimer: This content is for awareness purposes only.