(adsbygoogle = window.adsbygoogle || []).push({});
Classes of Malicious Software
Two of the most common types of malware are viruses and worms. These types of programs are able to self-replicate and can spread copies of themselves, which might even be modified copies. To be classified as a virus or worm, malware must have the ability to propagate. The difference is that a worm operates more or less independently of other files, whereas a virus depends on a host program to spread itself. These and other classes of malicious software are described below.
*
Viruses
A computer virus is a type of malware that propagates by inserting a copy of itself into and becoming part of another program. It spreads from one computer to another, leaving infections as it travels. Viruses can range in severity from causing mildly annoying effects to damaging data or software and causing denial-of-service (DoS) conditions. However, some viruses overwrite other programs with copies of themselves, which destroys the host program altogether. Viruses spread when the software or document they are attached to is transferred from one computer to another using the network, a disk, file sharing, or infected e-mail attachments.
Worms
Computer worms are similar to viruses in that they replicate functional copies of themselves and can cause the same type of damage. In contrast to viruses, which require the spreading of an infected host file, worms are standalone software and do not require a host program or human help to propagate. To spread, worms either exploit a vulnerability on the target system or use some kind of social engineering to trick users into executing them. A worm enters a computer through a vulnerability in the system and takes advantage of file-transport or information-transport features on the system, allowing it to travel unaided.
Trojans
A Trojan is another type of malware named after the wooden horse 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 back doors 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 e-mail attachment or downloading and running a file from the Internet.
Bots
"Bot" is derived from the word "robot" and is an automated process that interacts with other network services. Bots often automate tasks and provide information or services that would otherwise be conducted by a human being. A typical use of bots is to gather information (such as web crawlers), or interact automatically with instant messaging (IM), Internet Relay Chat (IRC), or other web interfaces. They may also be used to interact dynamically with websites.
Bots can be used for either good or malicious intent.Bots rarely announce their presence with high scan rates, which damage network infrastructure; instead they infect networks in a way that escapes immediate notice.
Best Practices for Combating Viruses, Worms, Trojans, and Bots
The first steps to protecting your computer are to ensure that your OS is up to date. This means regularly applying the most recent patches and fixes recommended by the OS vendor. Secondly, you should have antivirus software installed on your system and download updates frequently to ensure that your software has the latest fixes for new viruses, worms, Trojans, and bots. Additionally, you want to make sure that your antivirus program can scan e-mail and files as they are downloaded from the Internet. This will help prevent malicious programs from reaching your computer. You may also want to consider installing a firewall.
Additional Definitions and References
Exploit
An exploit is a piece of software, a command, or a methodology that attacks a particular security vulnerability. Exploits are not always malicious in intent—they are sometimes used only as a way of demonstrating that a vulnerability exists. However, they are a common component of malware.
Back Door
A back door is an undocumented way of accessing a system, bypassing the normal authentication mechanisms. Some back doors 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 back doors for easier and continued access to a system after it has been compromised.
Rep & Thanks. Enjoy:carling: