Virus - Malware - Spyware - Differences and Specifics of Computer Infections

Virus - Malware - Spyware - Differences and Specifics of Computer Infections

When it comes to computer security, mistakes are often made, and the terms computer viruses, computer worms, and computer Trojans are often confused.

All three categories of malicious entities in the computer world fall under the category of malware.

However, there are certain differences among them, and understanding these differences can help provide better and more comprehensive computer protection. A computer virus "attaches" itself to a file (usually an executable file, but it can also be found in other files, especially those that execute certain scripts) and spreads by transferring itself to other computers. Computer viruses vary in the severity of the consequences that infected computers suffer. The consequences can range from benign, causing minor annoyances to the user (we remember one of the first viruses that, under the DOS operating system, caused letters on the screen to "fall" from their positions) to very severe consequences (such as file or program damage, and even hardware damage).

It's important to know that viruses do not spread on their own; they always require some user action, such as running a program infected with the virus. Therefore, a computer can contain a file that carries the virus, but the computer will not be infected, and the virus will not spread until the user performs an action with that file, thereby activating the virus.

Computer Worm

The most significant difference between a virus and a computer worm is the latter's ability to spread independently, without the user's help. Worms exploit vulnerabilities in information systems and spread from node to node in a network, almost always causing damage to the infected system (at the very least, they misuse network resources, reducing network bandwidth). The major danger from worms comes from their ability to replicate themselves both on the network and on the computer. Once a worm infects one computer, it can replicate itself on that computer and send not just one worm but thousands of copies, leading to a destructive effect on the compromised information system. An example of this type of propagation is a worm that replicates on an infected computer by sending copies to all addresses found in the user's email address book, and then the process repeats on each computer it reaches. This process repeats on every computer the worm encounters, ultimately having devastating consequences - infected computers can consume a large amount of memory or network resources (greatly reducing network bandwidth), causing the computers or services on them to stop functioning (Denial of Service - DoS).

Another danger from worms arises from their ability to open security vulnerabilities (backdoors) on computers, allowing unauthorized access to the infected computer and its data over the network.

Trojan Horse

Computer Trojans are named after the mythological Trojan horse because they appear at first glance to be ordinary useful programs but ultimately cause harm to the computer on which they are installed. Computer users typically install them on their own computers, as the Trojan horse appears to be a program from a completely legitimate source that will perform a desired function (some Trojans even do that!). After successfully infecting a computer, a Trojan horse can perform various unwanted actions, ranging from benign but annoying ones (such as changing desktop backgrounds or displaying various messages) to very serious security problems (such as file deletion and, most notably, the opening of security vulnerabilities on computers, allowing unauthorized access to the infected computer and its data). Unlike computer viruses and worms, Trojans do not spread by infecting other files or replicate independently.

In addition to the threats of computer viruses, computer worms, and Trojans, there are other terms in the field of computer security that often confuse users.

Malware is short for "malicious software," and it refers to any malicious program created with the intent of damaging an infected computer without the user's consent. This is a general term that encompasses all computer threats, such as viruses, worms, Trojans, spyware, and more.

Spyware is a program that is installed on a computer without the user's conscious consent and intercepts or partially takes control of user-computer interactions. Spyware can collect data from users and relay it to a third party. According to the United States Computer Emergency Readiness Team (US-CERT), spyware commonly collects data related to:

Internet activity (websites visited, duration of visits, etc.),

email and contacts,

clipboard contents,

keystrokes (keylogging),

screenshots, and

network traffic.

You can check out our range of antivirus solutions at - NOD32 Antivirus- Malware- Spyware.