> For the complete documentation index, see [llms.txt](https://nuclei-av.gitbook.io/malware-handbook/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://nuclei-av.gitbook.io/malware-handbook/malware/types-of-malware.md).

# Types of Malware

* Virus: A type of malware that replicates itself by modifying other computer programs and inserting its own code.
* Worm: A standalone malware computer program that replicates itself in order to spread to other computers.
* Trojan: A type of malware that is often disguised as legitimate software. Trojans can be employed by cyber-thieves and hackers trying to gain access to users' systems.
* Ransomware: A type of malware which threatens to publish the victim's data or perpetually block access to it unless a ransom is paid.
* Spyware: A type of malware that is designed to gather information about a person or organization without their knowledge.
* Adware: A software that automatically displays or downloads advertising material (often unwanted) when a user is online.
* Scareware: A type of malware that uses social engineering to cause shock, anxiety, or the perception of a threat in order to manipulate users into buying unwanted software.
* Rootkit: A collection of software tools that enable an unauthorized user to gain control of a computer system without being detected.
* Dropper: A type of malware that has been designed to "drop" or install itself or other viruses onto a computer.
* Downloader: A type of malware that primarily focuses on downloading and installing other malware onto the infected system.
* Backdoor: A method of bypassing normal authentication procedures, usually over a network connection, to gain remote access to a computer system.
* Keylogger: A type of malware that records every keystroke a user makes on the keyboard without the user's knowledge, with the intent of capturing sensitive information like usernames, passwords, and credit card details.
* Infostealer: A type of malware that is designed to seek out and steal important data from the victim's computer, such as personal and financial information.