What is Malware?

Malware (combination of “malicious” and “software”) refers to a variety of malicious programs. The software is intended to damage or disable computers and computer systems, and also distribute malware and viruses. It can take the form of executable code, scripts, active content, and other software.

Malware with common characteristics (such as having the same authors) and code base are grouped into a malware family.

Example: Conficker

Malware Types

Adware

Displays advertisements, redirects search requests to advertising websites, and collects marketing data.

Botnet

A botnet (combination of “robot” and “network”) is a network of computers that perform coordinated actions. Instructions are received from a Command & Control Server (C&C Server). Computing power and network connections are harnessed through host computers. The effectiveness of a botnet is based on its size, network bandwidth, and processing power.

Browser hijacker

Modifies browser settings without permission to inject malvertisements. It may replace the existing homepage, error page, or search engine with its own version.

Crypto-miner

Refers to software programs and malware components developed to take over a computer's resources and use them for cryptocurrency mining without explicit permission.

Ransomware

Locks the user from the compromised device, denying them access.

Remote Access Trojan (RAT)

A trojan that allows attackers to remotely monitor and control a computer or network. Their main functions are for spying, hijacking, or destroying computers. Though similar to remote access programs with legitimate remote access purposes made for tech support and file sharing, these are installed without the user’s knowledge.

Riskware

Legitimate programs that can cause damage if they are exploited.

Rootkit

Allows an unauthorized user to gain elevated, administrative privileges on a computer system. Once obtained, rootkits may attempt to hide themselves.

Spambot

A type of botnet specifically designed to collect or harvest email addresses from the Internet and send emails at high volumes, also known as “spam.” Spambots account for large percentages of global spam activity. With few exceptions, spambots that are not attributable to specific malware families are classified as Spam Propagation events.

Spyware

Collects information about the user and device. It’s often installed without consent. The information might contain reports about online browsing habits or purchases. It can also be modified to record behaviors, such as keystrokes.

Trojan

Disguised as legitimate software for the purposes of gaining access to systems. Unlike viruses and worms, trojans are unable to self-replicate.

Worm

Unlike a virus, worms are stand-alone malicious programs that can self-replicate and propagate via computer networks. They don't need a host program to run, self-replicate, and propagate.

Once a worm has made its way onto a system, usually via a network connection or as a downloaded file, it can then make copies of itself and spread via the network or internet connection, infecting any inadequately-protected computers and servers on the network. Since each subsequent copy of a worm can also self-replicate, infections can spread rapidly.