What is a computer virus and malware? How can one differentiate the both?

Many people get confused with malware and viruses, as both the names were used alternatively in most cases. These terms are interchanged with each other for representing viruses.

A computer virus is a piece of code that has the tendency to replicate by itself and occupy the most space freely available in the host I.e., a computer, whereas malware is a malicious program that is specifically designed to damage the host system wherever it is installed.

All computer viruses are a type of malware but not all malware are viruses. Malware, when activated, has the tendency to capture sensitive data like credit or debit card information stored on the system and leak that information to the malware developer.

Viruses make copies of themselves in a brief time and spread to all the linked devices as fast as possible. Viruses can be transmitted through USB devices (removable storage), infected websites, email attachments, and network routers. Viruses, when entered PC, mostly attack the applications and the email services.

Viruses are a type of malware, and the viruses that are most observed all over the internet are as follows –

• Boot Sector Virus – A boot sector virus is a type of malware that infects the system’s Boot Partition or Master Boot Record (MBR) of a hard disk. These viruses prevent the startup of the operating systems and prevent the installation or the execution of any security programs.
• Multipartite Virus – A multipartite virus is a fast-moving virus that uses files infectors or boot infectors to attack the boot sector and executable files simultaneously. The multipartite virus can affect both the boot sector and the program files at the same time, thus causing more damage than any other type of virus.
• Spacefiller Virus – Also known as Cavity virus or Chernobyl. These viruses are rare computer viruses that try to install themselves by filling in the empty sections of the files. As these viruses occupy the empty spaces of the files, the size of the files does not get changed which makes the viruses impossible to get detected.
• Resident Virus – A resident virus is a kind of computer virus that hides and stores itself within the computer memory, which then allows it to infect any file that is run by the computer, depending on the programming of the virus.
• Polymorphic viruses – These polymorphic viruses are intelligent viruses that modify themselves to avoid detection. These viruses use encryption methods to stay safe from detection and during each time of infection these viruses use different encryption keys to protect their codes. These viruses depend on mutation engines for decryption routines every time they infect the machine.
• File Infector Viruses – The name itself indicates that these viruses infect the files i.e., executable files most commonly. These file infector viruses either damage the executable files or make them unusable. These viruses have the tendency to overwrite the code or insert the infected code in the executable files.
• Direct Action Viruses – These viruses do not do any harm until the person executes the file attached with malicious code. These direct-action viruses deliver the payload immediately after executing the file. These viruses stay inactive or dormant until a specific action is taken or the timeframe for the dormancy passes.
• Macro Viruses – The name ‘Macro’ is given to these viruses because the code used for these viruses is written in Macro language. This macro language is deployed in software applications like Microsoft Word, Excel, etc., to automate the processes with a few clicks efficiently. These macro viruses do not infect files yet they infect operating systems and software applications.

Malware is a malicious program designed to harm the computer for the benefit of a third party. The most widely seen malware all over the internet are as follows –

• Worm – It is simply a self-replicating program. It does not do any harm to the personal computer; however, it consumes the free space available. Worms quickly spread from one device to another device through removable USB drives.
• Trojan – Also known as Trojan horse virus, sometimes. These malware programs are specially designed to take control over the personal computer or device. This trojan malware is designed to damage, disrupt, steal, or carry out harmful actions on the infected devices. This malware usually tricks you by appearing as an authentic application. Trojans do not infect the computer until someone executes them.
• Adware – A malicious program that bombards your computer, laptop, or any device with irrelevant advertisements (ads) through annoying pop-ups, interstitial, and banner ads. The programmer of the Adware will generate the revenue for those ads displayed on your device without your permission.
• Scareware – These malicious programs will bullshit you into purchasing unnecessary software by scaring you that your computer or device is infected with malware or a virus. The program that gets downloaded after the purchase is malware itself sometimes or some unnecessary tools that you do not need. These programs just trick you into purchasing and the programmer of the scareware will get the revenue.
• Spyware – The name itself indicates that it spies on your actions. These malicious programs are designed to spy on the user. These programs have the tendency to record the keystrokes that are used to steal login credentials and sensitive data such as online banking details, credit, or debit card details, etc. These programs even have the tendency to track your location by turning on device GPS and watching you live by turning on your device camera.
• Ransomware – These malicious malware programs are specifically designed to demand amounts from the affected users. These programs have the tendency to lock up important files and folders, or entire devices and demand a ransom amount in compensation to unlock them. These programs are new in the web world; however, they are very nasty.
• Rootkit – These malicious programs are specially programmed to escape the traditional detection methods. These programs deeply bury themselves in your computer or devices which makes them difficult to get detected and removed. These malware programs perform a wide variety of illegal activities such as stealing user information (just like spyware), sending spam emails, participating in DDoS attacks, or granting remote access to your device for the malware programmer.

When a computer or a device is attacked by viruses then some unusual activities happen in the infected computer or device that the user is going to clearly observe. The most common things that we notice in virus-infected systems are as follows –

• The computer or device will start hanging up more frequently and repeatedly.
• The computer or device will get heated up as the malicious viral codes run in the background continuously.
• The free space of the system or device will be occupied soon after the infection due to the copy itself nature of viruses.
• The files will either get corrupted or get damaged. Sometimes the entire data including files and folders will get wiped out.
• The computer or device will reboot more frequently as the files of the main operating system get damaged or corrupted.
• The performance and speed of the computer or device will be slowed down due to excessive resource usages such as CPU and RAM.
• The various vital functions of the computer or device will get affected due to the insertion of malicious codes in the executable files of different applications.

When a computer or a device is infected by malware then the following unusual activities are going to happen on your personal computer or any device –

• The computer or device will be bombarded with advertisements including annoying pop-ups, interstitial, and banner ads.
• The computer or device will get unwanted notifications like your device is infected with malware or a virus that scares you and tricks you for payment.
• Your personal information and privacy will be exposed.
• Sensitive information like online banking details, credit, or debit card details will be leaked through keystrokes logging.
• Your location and daily activities will be tracked. You will be spied live.
• You will be tricked for ransom payment to get your own content unlocked.
• The computer or device will start sending spam emails automatically to your friends, family, and contacts.
• Hackers will gain remote access to your computer or device.
• The computer or device will also participate in DDoS attacks.
• The computer’s heating up and hanging are common issues, as the malware software runs continuously in the background.
• The performance and speed of the device will be greatly affected due to excessive resource usage.

These are the most common issues that are observed in virus and malware-infected systems or devices. If any of the above issues are found in a personal computer or device, then we can easily conclude that there is a presence of malware or a virus in the system.