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What Is Malware – Types for Defenders
What Is Malware – Types for Defenders Malware is software made to harm, spy on, encrypt or control systems. Types: virus, worm, trojan, ransomware, spyware, rootkit. Virus needs a host file. Worm spreads by itself. Trojan hides in a useful-looking file. Ransomware encrypts your files for money. Wann
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What this card says
What it is
Malware is software made to harm, spy on, encrypt or control systems.
Types: virus, worm, trojan, ransomware, spyware, rootkit.
Quick meanings
Virus needs a host file. Worm spreads by itself. Trojan hides in a useful-looking file. Ransomware encrypts your files for money.
Real incident
WannaCry (2017) was a worm-like ransomware that spread using a Windows SMB bug and locked files worldwide.
Defence: patch fast, filter email, keep offline backups.
| Type | Simple idea | Blue focus |
|---|---|---|
| Virus | Needs a host file; spreads when that file runs / is shared | Scan files; block autorun; least privilege |
| Worm | Self-spreads over network (often no user click) | Patch, segment, block lateral SMB/RDP |
| Trojan | Looks useful; hides payload (fake tool, cracked installer) | Reputation, allowlisting, signed software |
| Ransomware | Encrypts / locks; demands payment | Backups, EDR, least privilege, isolate |
| Spyware | Steals keystrokes, cookies, files | EDR, MFA, browser hardening |
Learn more in the lesson: 39.1 What Is Malware – Types for Defenders