Malware, short for "malicious software," is a broad category of software specifically engineered to perform unauthorized and often harmful actions on a computer system, network, or device. Its primary characteristic is that it operateswithout the owner's consent. Malware is the primary tool used by cybercriminals to achieve various objectives, ranging from financial gain to corporate espionage and simple disruption.

Malware encompasses several distinct types, each with its own method of infection and goal:

Viruses and Worms: Designed to spread from one file or computer to another, often damaging data or consuming network bandwidth along the way.

Trojan Horses: Programs that disguise themselves as legitimate software to trick users into installing them, only to reveal a malicious "payload" once active.

Ransomware: Encrypts the victim's data and demands payment for the decryption key.

Spyware and Stealers: Secretly monitor user activity or steal sensitive information like passwords and credit card numbers.

Rootkits: Specialized malware designed to provide high-level "root" access while remaining hidden from the operating system and antivirus software.

Ethical hackers study malware to understand how to defend against it. This involves analyzing "Attack Vectors" (how malware enters a system), "Persistence Mechanisms" (how it stays there), and "Command and Control" (how it communicates with the attacker). Protecting against malware requires a multi-layered defense strategy, including updated antivirus software, strictAcceptable Use Policies (AUP), and regular vulnerability scanning to close the gaps that malware exploits to infect systems.