Computer Virus

In the cutting-edge age, in which generation reigns incredibly, the computer virus has grown to be synonymous with malicious software that infiltrates and compromises virtual systems. These covert entrepreneurs of cyber disruption have advanced drastically, given that their inception is developing in complexity and causing considerable havoc. Computer viruses are unwanted software programs or pieces of code that interfere with the functioning of the computer. They spread through contaminated files, data, and insecure networks. Once it enters your system, it can replicate to produce copies of itself to spread from one program to another program and from one infected computer to another computer. So, we can say that it is a self-replicating computer program that interferes with the functioning of the computer by infecting files, data, programs, etc.

There are many antiviruses, which are programs that can help you protect your machine from viruses. It scans your system and cleans the viruses detected during the scan. Some of the popular antiviruses include Avast, Quickheal, McAfee, Kaspersky, etc.

Methods of Propagation

• Physical Media: Viruses unfold via inflamed bodily devices like floppy disks, CDs, and USB drives.
• Email Attachments: Viruses are frequently transmitted through malicious electronic mail attachments.
• File Sharing: Shared networks and peer-to-peer sharing can facilitate virus transmission.
• Malicious Websites: Infected websites and strength-by means of manner of downloads can cause virus infections.
• Social Engineering: Viruses leverage misleading tactics to trick customers into executing them.
• Network Exploits: Some viruses make the most community vulnerabilities to infiltrate and spread.
• USB Drives: Viruses can be transferred through infected USB drives and special peripheral gadgets.

Types of Computer Virus:

Overwrite Virus:

It is the simplest computer virus that overwrites the code of the host computer system's file with its own malicious code. The content of the infected file is replaced partially or completely without changing the size of the file. Thus, it destroys the original program code by overwriting it with its defective code. The infected files must be deleted or replaced with a new copy as this virus cannot be removed or disinfected.

Append Virus:

As the name suggests, this virus appends its malicious code to the end of the host program's file. After that, it alters the file's header in a way that the file's header is redirected to the start of the malicious code of the append virus. Thus, this code is executed each time the program runs. However, it does not destroy the host program; rather, it modifies it in a way that it holds the virus code and enables the code to run itself.

Macro Virus

Macro viruses are embedded in files, collectively with Microsoft Word or Excel files. They use the macro language in those files to infect and propagate to other documents even as opened.

Boot Virus

Boot region viruses infect the Master Boot Record (MBR) of a garage device, making it hard to eliminate. When an inflamed tool is booted, the virus activates and may spread to exceptional associated devices.

Resident Virus

Resident viruses embed themselves in the PC's reminiscence, making them tough to discover and eliminate. They can infect documents as they are opened or closed.

Non-resident Virus:

Non-resident viruses do not embed themselves in the PC's memory. Instead, they infect documents at once and depend upon the host document for execution.

Multipartite Virus

Multipartite virus spreads and infects in multiple ways. It infects both the boot sector and the executable files stored on the hard drive simultaneously. When you turn on a computer, the boot sector virus is triggered as it latches on to the hard drive, which has the data for starting up the computer. Once it is triggered, the program files also get infected.

File Infector Virus

It is one of the most commonly found computer viruses. These viruses connect themselves to executable files (e.g., .exe, .com, .dll) and activate while the infected report is executed. They can spread to other files while the inflamed program is administered.

Computer Worm

A Computer worm is similar to a virus but is technically different from the virus. While worms are distinct from viruses in that they don't require a host file, they're still a form of malware. Worms self-replicate and spread across networks and devices, often exploiting vulnerabilities.

Trojan Horse

A Trojan horse is malware like a virus or a worm. However, it is technically one-of-a-kind from the virus. While worms are terrific from viruses in that they don't require a bunch of reports, they're, however, a form of malware. Worms self-replicate and spread throughout networks and gadgets, frequently exploiting vulnerabilities.

Cavity virus:

It is also known as a spacefiller virus. As the name suggests, this virus tends to install itself by occupying the empty sections of a file. It is not easy to detect this virus as it fills the empty spaces without changing the size of the file.

CMOS Virus:

It infects the CMOS, which stands for complementary metal-oxide semiconductor and is a memory chip that contains the system configuration. This virus can erase or reset the system configuration.

Companion Virus:

Companion viruses do not regulate the host file directly. Instead, they create an accomplice file with a similar call and icon, tricking users into running the virus.

Encrypted Virus:

It encrypts its payload to make its detection more difficult. It comprises two parts: an encrypted virus body and a decryptor, which decrypts the virus when it is executed. After decryption, the virus can execute itself in order to replicate and become a resident. Furthermore, it is different from cryptolocker, which is a computer virus that encrypts the hard drive data and holds it for ransom.

Executable Virus:

It is a non-resident computer virus that resides in an executable file. Whenever the infected file is executed, it infects the other files.

Polymorphic Virus:

Polymorphic viruses trade their code or look with every contamination, making it difficult for antivirus applications to locate the use of traditional signature-based techniques.

Rabbit Virus:

It is also known as a wabbit or a fork bomb. It is capable of creating new processes, and each of the new processes further creates new processes. This process continues until this virus utilizes all the available resources in the system and, the system falls short of resources. It may cause the target system to slow down and crash. For example, it is like an Infinite loop that repeatedly creates processes that consume lots of CPU cycles and operating system resources.

Stealth Virus:

It is a hidden computer virus, which specifically attacks operating system processes. It usually hides itself in partitions, files or boot sectors and is capable of going unnoticed during antivirus or anti-malware scans, i.e., it can avoid detection intentionally.

Symptoms of a Computer Virus:

There are many warning signs or symptoms which show that a computer is infected with a virus, some of which are as follows:

• Slow computer performance: The machine may work slowly, e.g., it will take more time to open or shut down the computer or while opening a file, document, computer application, etc. The operating system and internet speed may get slow.
• Frequent pop-ups: A virus may cause unusual frequent pop-ups on your window.
• Hard Drive issue: The hard drive may exhibit unusual high activity even when it is not in use. It may cause unwanted changes to your hard drive and may freeze or crash this device.
• Frequent crashes: One may experience frequent sudden system crashes while playing games, watching videos, or doing some other work using the infected system. A blue screen appears when it crashes.
• Unknown programs: Unwanted programs may open or start automatically when you start your computer. You can see these programs in your computer's list of active applications. Sometimes, the window shuts down unexpectedly without any reason.
• Unusual activities: Your machine may perform differently, such as you may not be able to log into your accounts, to delete the corrupt files, and Blue Screen of Death (BSOD) may appear frequently, and more. Furthermore, the hardware, software, or OS may start malfunctioning leading to crashing the system abruptly.
• Impaired security solutions: Sometimes, security measures taken by you, such as antivirus may not work smoothly due to virus attack on your computer.
• Network issue: Sometimes, you experience high network activity even if you are not connected to the internet and vice versa.
• Unnecessary advertisement: We often see advertisements while browsing, but if you see them even when you are not browsing, it may indicate a virus on your computer.
• Display problems: You may experience different colors in your display if your computer is affected by a virus.
• Affected Applications: Some viruses are developed to affect specific applications. Consequently, some applications may not work on your computer if it is infected.
• Blocked by Antivirus Sites: An antivirus site may deny access to a computer that is infected by a virus.
• Dialog Boxes: Many dialog boxes keep appearing suddenly on your screen.
• Printer Issues: A printer attached to an infected computer may print documents without getting any command or in an inappropriate manner.
• Changed Homepage: Your home page may get changed without any effort from your side. For example, you may see a new toolbar on your screen, and you may be redirected to a different web address instead of the page visited by you initially.
• Strange messages: One may see strange messages on a computer screen such as error messages.

Countermeasures and Mitigation

• Antivirus Software: Antivirus packages are designed to come upon, quarantine, and get rid of viruses from a gadget. These gear use signatures and heuristics to pick out malicious code.
• Firewalls: Firewalls act as a barrier between a community and potential threats, preventing unauthorized admission to and the spread of viruses.
• Patch Management: Keeping software, working systems, and programs updated with the current safety patches can help near vulnerabilities that viruses take advantage of.
• Email Filtering: Employing email filtering systems can block malicious attachments and hyperlinks, reducing the threat of e-mail-borne viruses.
• User Education: Educating clients about steady online practices, which include no longer clicking on suspicious hyperlinks or starting unsolicited email attachments, is a vital safety in opposition to social engineering processes.
• Network Segmentation: Segregating networks into smaller, remoted segments can restrict the spread of viruses inside the occasion of an infection.
• Behavior Analysis: Advanced safety solutions use behavior evaluation to come upon unusual styles and sports, which could mean the presence of a deadly disease.
• Backup and Recovery: Regularly backing up facts and having a recovery plan in the vicinity can mitigate the effect of information loss due to viruses.
• Security Updates: Staying informed about modern-day threats and incredible security practices is crucial for effective protection closer to viruses.
• Regulatory Compliance: Many industries have regulatory necessities for records safety. Compliance with the regulations can assist guards in guarding competition against viruses and other cyber threats.