Definition trojan worm virus

To keep it brief, a Trojan uses trickery and social engineering to deceive people into running it. For example, a Trojan may pretend to be legitimate software. A worm is a type of Trojan because it normally relies on social engineering to attack systems.

Some people think that a computer worm and computer virus are the same things because the two behave similarly. They may even use the terms like "worm computer virus" or "worm virus malware. The defining difference between a virus and a worm is that viruses rely on human action for activation and need a host system to replicate.

Over the years, there have been some particularly devastating worms. Some worms have caused billions in damage. Here is a brief list of some infamous ones:. Many of the symptoms of a computer worm are like that of a computer virus. For example, you may have a computer worm if your computer slows down, freezes, crashes or throws up error messages.

You may also notice that files are missing or corrupted or that your hard drive's space is rapidly depleting inexplicably. Additionally, you may see alerts from your firewall about a breach. Like other forms of malware — computer worms can be stopped with the right antivirus and anti-malware software and safe computing practices. Also, update your essential software regularly to shield your computer from vulnerabilities like the wormable Windows flaw and the like.

The official Malwarebytes logo The official Malwarebytes logo in a blue font. Online Privacy. More advanced worms leverage encryption, wipers, and ransomware technologies to harm their targets. A Trojan is another type of malware named after the wooden horse that the Greeks used to infiltrate Troy.

It is a harmful piece of software that looks legitimate. Users are typically tricked into loading and executing it on their systems. After it is activated, it can achieve any number of attacks on the host, from irritating the user popping up windows or changing desktops to damaging the host deleting files, stealing data, or activating and spreading other malware, such as viruses.

Trojans are also known to create backdoors to give malicious users access to the system. Unlike viruses and worms, Trojans do not reproduce by infecting other files nor do they self-replicate.

Trojans must spread through user interaction such as opening an email attachment or downloading and running a file from the Internet. Bots often automate tasks and provide information or services that would otherwise be conducted by a human being. They may also be used to interact dynamically with websites.

Bots can be used for either good or malicious intent. In addition to the worm-like ability to self-propagate, bots can include the ability to log keystrokes, gather passwords, capture and analyze packets, gather financial information, launch Denial of Service DOS Attacks , relay spam, and open backdoors on the infected host. Bots have all the advantages of worms, but are generally much more versatile in their infection vector and are often modified within hours of publication of a new exploit.

They have been known to exploit backdoors opened by worms and viruses, which allows them to access networks that have good perimeter control. Bots rarely announce their presence with high scan rates that damage network infrastructure; instead, they infect networks in a way that escapes immediate notice.

Advanced botnets may take advantage of common internet of things IOT devices such as home electronics or appliances to increase automated attacks. Crypto mining is a common use of these bots for nefarious purposes. Advanced malware typically comes via the following distribution channels to a computer or network:. A set of stealthy and continuous computer hacking processes, often orchestrated by a person or persons targeting a specific entity.

An APT usually targets either private organizations, states, or both for business or political motives. APT processes require a high degree of covertness over a long period of time. The "advanced" process signifies sophisticated techniques using malware to exploit vulnerabilities in systems. The "persistent" process suggests that an external command and control system is continuously monitoring and extracting data from a specific target.

The "threat" process indicates human involvement in orchestrating the attack. Software that generates revenue for its developer by automatically generating online advertisements in the user interface of the software or on a screen presented to the user during the installation process. The software may generate two types of revenue: one is for the display of the advertisement and another on a "pay-per-click" basis if the user clicks on the advertisement.

An undocumented way of accessing a system, bypassing the normal authentication mechanisms. Some backdoors are placed in the software by the original programmer and others are placed on systems through a system compromise, such as a virus or worm.

Usually, attackers use backdoors for easier and continued access to a system after it has been compromised. Adversaries may use bootkits to persist on systems at a layer below the operating system, which may make it difficult to perform full remediation unless an organization suspects one was used and can act accordingly.

Software that modifies a web browser's settings without a user's permission to inject unwanted advertising into the user's browser. Security Topics. We have updated our Privacy Policy. Enterprise PKI Platform Secure yourself against unauthorized access, email compromise, and document tampering with our enterprise tested, cloud-based PKI. CertCentral Certificate Manager Discover and manage every certificate in your ecosystem—all on one pane of glass.

Go Beyond Encryption Protect your sites with end-to-end automation solutions. If you have certificates issued before December 1, , you will need to take action. More Information. Expired Certificate? Renew Now. Support by Category Enterprise Retail Partner. Why Us. Malicious Programs The most common blunder people make when the topic of a computer virus arises is to refer to a worm or Trojan horse as a virus.

Knowing the Differences Can Help You to Better Protect your Computer A computer virus attaches itself to a program or file so it can spread from one computer to another, leaving infections as it travels. Change Language. Related Articles. Table of Contents. Improve Article. Save Article. Like Article. Last Updated : 15 Jun, Virus : Virus is a computer program or software that connect itself to another software or computer program to harm computer system.

When the computer program runs attached with virus it perform some action such as deleting a file from the computer system.

Worms : Worms is also a computer program like virus but it does not modify the program. It replicate itself more and more to cause slow down the computer system.