Malware

Malware is a term used to describe any software intentionally designed to cause disruption. It is a portmanteau, or a blend of words, combining "malicious" and "software." This software aims to damage computers, servers, or networks. It can also be used to leak private information or gain unauthorized access to systems. In some cases, malware deprives users of access to their own data. It can even interfere with a user's privacy without them knowing.

Malware poses massive challenges for both individuals and global businesses.

Researchers classify malware into several distinct sub-types based on how they behave. A computer virus is software that hides inside a seemingly harmless program. It produces copies of itself by inserting its code into other files. This process is similar to how biological viruses spread. A worm is different because it is a stand-alone program. It does not need to infect other files to spread. Instead, it transmits itself across a network to find new computers.

A Trojan horse uses deception to enter a system. It masquerades as a regular, benign utility to trick a user into installing it. Once activated, it carries a hidden, destructive payload.

Other specialized types of malware include ransomware, spyware, and adware. Ransomware is used to hold data for extortion. Spyware and keyloggers are used to steal confidential information, such as passwords or bank numbers. Adware is designed to generate revenue for its operator. Some malware acts as a rootkit, which is a package designed for concealment. Rootkits modify the host operating system to hide the malware from the user. They can prevent harmful processes from appearing in a system's list of active tasks. This makes the infection very difficult to detect.

Malware can also create a backdoor in a computer system. A backdoor is a program that allows an attacker to maintain unauthorized remote access. Attackers often use a Trojan or a worm to bypass security and install this backdoor. Once installed, the attacker can enter the machine without the user's knowledge. Some malware also functions as a cryptominer. This type of software uses the computer's processor to mine digital currency. This can cause the device to run slower, emit more heat, or make more fan noise. Some cryptominers only run during idle times to avoid being noticed.

The history of self-reproducing software began with mathematical theories. In 1949, John von Neumann presented theories about self-reproducing automata. He showed that, in theory, a program could reproduce itself. This was a major finding in computability theory. Later, Fred Cohen conducted experiments with computer viruses. He confirmed von Neumann's ideas and studied how malware could use encryption to hide itself. In the 1980s, the first IBM PC virus, called (c)Brain, appeared in Pakistan. It was created by the Farooq Alvi brothers and spread via boot sectors on floppy disks.

The scale of malware has grown significantly over the years. In 2017, there were 669,947,865 malware variants. This was twice the number found in 2016. Cybercrime is also a massive economic issue. It was predicted to cost the world economy US$6 trillion in 2021. This cost is increasing at a rate of 15% per year. Modern malware has even moved toward targeting critical infrastructure. For example, some software is designed to attack electricity distribution networks. This shifts the impact from personal loss to large-scale societal disruption.

Malware is used for many different purposes in the modern world. While some early programs were just experiments or pranks, most are now designed for profit. Criminals use "zombie computers" to send spam or host illegal data. They also use them for distributed denial-of-service attacks to extort money. Beyond crime, malware is used for political sabotage. The Stuxnet program was engineered to interfere with specific industrial control systems. Other attacks, such as Shamoon, have targeted large corporations like Saudi Aramco. Even small USB devices, like fans or toys, can spread malware if they are not manufactured securely.