Malware is a malicious program that attacker programmed and sent to a target in order to harm computer, disrupt functions of a computer system or to steal sensitive information. A programmed code that is written to perform these harmful task are malicious code and they are software called Malware (MALicious softWARE). Attackers use different vehicles to deliver malware to their targets, malware attacks and means for delivering malware may include through Electronic mail attachment, Instant Message, Network Messaging, Internet Web Download, Trojan Horse, etc. Spamming is a useful vehicle that malware attackers use repeatedly to deliver harmful program to large numbers of target.
There are various types of malware and their use depending on intention of attacker. Common intention of malware programmer includes, Crashing a device, Disrupting function of a device, deleting of data, destroying of data, overloading of storage media, stealing of sensitive information, etc. Below explained different types of existing malware.
Types of Malware
Virus: Virus is a harmful program that can infect programs on a device, A virus attaches to a host program and propagates when the infected program is executed. A virus replicates from infected program to another program whenever infected program executes, virus moves from one computer to another whenever infected program is copied or transmitted to a computer. Virus codes may contained malicious instruction that may crash, cause damage or change function of a computer.
Worm: Unlike a virus, worm does not need to attach to any program. Worms are self-replicating malware that copy itself from one computer to another in a network without knowledge of the a computer user.
Keylogger: Keystroke logger or keylogger is a monitoring or surveillance software that logs and captures the keystroke on a keyboard, keylogger can be found as hardware of software which known as hardware keylogger or software keylogger which they are all considered to be a type of Spyware Tools. Keylogging is the process and practice of recording the keystroke and activities of a computer user or a victim and keys typed and other activities by computer user are recorded and recorded information is obtained or dispatched without the user’s knowledge.
Spyware: Spyware behaviors are similar to keylogger but in many cases spyware captures and records critical information. Many spyware programs are programmed to capture and monitor what web sites visited including all pages browsed, windows and directory opened on operating system and activities on a computer. Spyware software is installed on a computer without the user’s knowledge which monitors user activity and transmits it to another computer using protocols.
Trojan Horse: Trojan is named Trojan Horse due to what malicious purpose it contains. Trojan in a computer security is malicious software that appears to be a real and useful program to the user but would actually have a some harmful and malicious purpose. Trojan front-end is looking friendly and useful but it is Trojan horse because of what it contained in back-end. Trojan horse mislead a user to install it, when installed; a malicious program is silently installed. Trojans usually carry some harmful code like virus, worm or spyware.
Backdoor: A backdoor program works in background that is usually programmed and silently installed for bypassing authentication and it is quite difficult to detect by system user. Backdoor may sometimes installed with a program so that the program or system can be accessed quickly and easily any times. When a system is compromised by attacker, attacker may install a backdoor so that the compromised system can be accessed quickly any time through the backdoor program. Because of quick, easy and repeatable accessibility, attacker may have enough time to monitor user’s activities and carryout various fraudulent and harmful action against user’s system that may include creation, deletion, rename or modification of files, changing of system settings, uninstall useful programs, installation of hidden harmful software, tracking and recording of user’s activities, stealing of sensitive information like password, bank detail, login name, credit card detail, and many more.
Rootkit: A rootkit is a program designed to allow repeated privileged access to a computer while undetectable. A rootkit is a designed tools that enabled administrator-level access to a computer or network. Rootkit came out from two word namely “root” and “kit; meaning a root access on a computer system and a kit of tools that allow the access possible. When a rootkit is installed, the attacker/administrator of the rootkit has the ability to remotely create, modify or delete files, modify configurations on the machine and spy on user’s regular activities.
Web browser parasite: Browser parasite is also known as adware or malvertising program, it is unwanted media inform of image, flash, video or link that appears on web browser. This media may embed malicious codes that redirects to download or link to harmful program or web page after a click. Some internet advertiser also use this idea to display unwanted advertisement in order to protect their product or service or to generate income on advertisement.
Botnet: Botnet software allows an attacker to take complete control remotely of affected computer or group of computers. The work Botnet came from two words namely “robot” and “network” . Attacker usually compromise several computers and later organize with botnet software and control them remotely as a network called Zombie network or Botnet (bot network). The compromised machine that used for infecting other machine may also be referred to as a “zombie.” A collection of these infected computers is known as a “botnet.” A botnet maker (attacker) can use botnet (group of infected computers) remotely for several illegal purposes that may include Denial-of-service attack (DoS Attack) or Distributed Denial-of-service attack (DDoS Attack), Email Spam, installation of harmful software, stealing of sensitive information, etc.
Ransomware: Ransomware is fully understood as Ransom malware, ransomware is a type of malware that lock and prevents users from accessing their system file or program typically by encryption and attacker demands payment for decryption in order to retrieve and regain access. Usual motive of this attack is for financial gain in which attacker demands for money after successful attack. The victim of this attack is informed by attacker about the attack and attacker provides instruction on how to decrypt and recover it to regain access, the perpetrator will actually demand for anonymous payment such as cryptocurrency before doing the recovery.
Web bugs: A Web bug is also known as a Web beacon, is a file object that is inserted on a Web page or in an e-mail message to track user behavior. Web bugs can be used for fingerprinting and they are often used by spammers to validate e-mail addresses. A Spam email that includes a web bug can return confirmation to the spammer indicates that the message has been opened, which confirms that the email address is valid and email was delivered and opened by the recipient. web bugs placed on web can be used tracking a user or fingerprinting (information gathering) purpose, information web bug detects and obtain may include viewer’s IP address, browser type, OS type, time opened, etc.
Computer and mobile should Malware proof by the use of Anti-Malware Software on device. Installation of Anti-Malware software with regular scanning and updates reduces the risk of getting harmed by malicious program, specific anti-malware program detects and protects against specific malware program but there so many anti-malware programs existing in the market which work against multiple malware. Device users and network user should be security conscious about common malware attacks and The idea of knowing ‘Think before click and Think before Download” can also help in every situation.