What is malware and mention it's major categories? ?

Malware is a type of malicious software that is designed to disrupt, damage, or gain unauthorized access to a computer system. The major categories of malware include:

1. Viruses: These are programs that can replicate themselves and spread to other computers by attaching themselves to legitimate programs.

2. Worms: Worms are standalone malware programs that can replicate themselves and spread to other computers without needing to attach themselves to other programs.

3. Trojans: Trojans are malware programs that disguise themselves as legitimate software in order to trick users into downloading and installing them.

4. Ransomware: Ransomware is a type of malware that encrypts a user's files and demands payment in exchange for the decryption key.

5. Spyware: Spyware is malware that is designed to secretly monitor a user's activities and gather sensitive information.

6. Adware: Adware is malware that displays unwanted advertisements on a user's computer in order to generate revenue for the attacker.

7. Rootkits: Rootkits are malware programs that are designed to hide themselves and other malicious software from detection by antivirus programs.