Malwares – Virus, Worm, Trojan, Spyware, Adwares, Spam, Rootkits and Others

Malwares - Virus, Worm, Trojan, Spyware, Adwares, Spam, Rootkits and Others
Malwares – Virus, Worm, Trojan, Spyware, Adwares, Spam, Rootkits and Others

Malware stands for malacious software. It is a broad term that actually stands for malacious programs which distort computer operation, collect sensitive information by gaining access to private computer systems. Malware includes computer viruses, worms, trojan horses, rootkits, spywares and adwares.

Some of them are described below.

Virus stands for vital information resource under seige. It is a program that replicates itself on its own by inserting copies of itself into other programs or documents. It is designed to gain control over a computer without the owner’s knowledge. A virus is one of most common kind of attacks used by spammers and hackers. It can attack any part of your computer such as boot block, os, system area, files and application programs. Viruses can be cateogorized into different groups on the basis of their attack areas.

Types of Computer Virus

  1. Resident viruses: They permanently fix themselves into system memory (RAM) and get activated whenever Operating System is run. It infects all the files that are open thereafter. Eg. Randex, Meve, etc.
  2. Direct Action Virus: It came into action when a file containing the virus is executed. It infects the file in the folder that are specified in AUTOEXEC.BAT file path. Eg. Vienna Virus.
  3. Overwrite Virus: It deletes the information stored in a file and make them partially or completely unusable for future use. Eg. Way, Trj.Reboot, Trivial-88D.
  4. Boot Sector Virus: It infects boot sector of hard disk or floppy drive. It makes computer unable to boot. Eg. Polyboot.B
  5. Macro Virus: This kind of virus is triggered when a program capable of running a macro is executed. Eg. Melissa.A
  6. File System Virus: It infects the directory of your computer by changing the path that indicates the file location. Eg. Dir-2 virus.
  7. Polymorphic Virus: One can detect a virus through its signature. In order to avoid such detection, a polymorphic virus changes its signature each time it is installed. Eg. Elkern.
  8. Multipartite Virus: It can infect multiple parts of a system including boot sector, memory and files, which makes it difficult to detect and contain. Therefore, it is known as the multipartite virus.

Some of the most well knnown viruses over the year.

Year    Name of the Virus
1971    Creeper
1982    Elk Cloner
1988    The Morris Internet Worm
1990    Melissa
2000    I Love You
2001    Code Red
2003    SQL Slammer
2003    Blaster
2004    Sasser
2010    Stuxnet
2011    Trojan
2012    Rootkit
2014    Generic PUP
2014    Net Worm

Worm is a malware program that makes a copy of itself in order to infect other computers. It relies on security failures in the computer network to access its target computer. It does not need to attach itself to an existing program unlike virus. Eg. Bagle, I Love You, Morris and Nimda.


A trojan is a non-self replicating malware which appears to perform desired action by user, but grants unauthorized access to the user. The term “trojan” has been taken from Greek myhtological trojan horse, which is presented as a harmless gift to victims, but in reality, opposite to what it appears. Eg. Beast, sub7.zeus, ZeroAccess Rootkit.

Spyware is a malicious software that collects information and data of the user without his or her knowledge and sends the collected data to someone else. Spywares can harm you in a number of ways such as steeling your password, observing your browsing history, sending you targeted emails and so on. Eg. Finfisher, Zango and Zlob.

A rootkit activates with each time your system boots up. It is difficult to detect as it is activated before your system has completely booted. It allows the installation of hidden files and processes in your system. It can create hidden user accounts in your system. Moreover, it is able to intercept data from terminals, network connections and input devices.

Adware is a commonly used term to describe advertisement supported softwares. It is considered as a legitimate alternative offered to consumers who do not wish to pay for the software. However, softwares which show unwanted advertisements even after end of their usage are now considerd as the adwares.

Spams are unsolicited emails sent by a person or organisation by abusing the utility of free messaging services. According to one estimate, half of the internet traffic is consumed by the spams.

It is the attempt to acquire sensitive information such as usernames, passwords, and other credentials (such as credit card or debit card details) by masquerading as a trustworthy entity in an electronic communication.

It is a technique to access the unauthorized data by spoofing (masquerading or imitating) the credential data of person or organization.

Salami Technique
It is gaining unauthorized access to accounts of multiple users maintained by the system and diverting data or money in small amounts to one centralized system. It is commonly used in financial attacks.

Hacking is the practice of modifying the features of a system, in order to prevent authorized authors from accessing the resources.

Cracking is another term used for hacking, but the only difference here is that the attacker attacks the targeted computer for financial gains.

Symptoms of Malware Attack
Some of the primary symptoms of a malware attacks are following

  1. Odd textual or graphical messages on display screen
  2. System runs slower
  3. Some files are missing
  4. Some files are not properly working or completely stopped working
  5. System crashes and restarts over and over
  6. The mouse pointer changes its graphics
  7. Unexpected sounds and music in background

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