Computer Virus

What Is a Computer Virus?

A computer virus is a collection of self-replicating instructions or program codes embedded within computer programs. Its purpose is to disrupt computer functionality by damaging specific functions or data. These malicious programs, commonly referred to as viruses, share characteristics with biological viruses. They exhibit infectivity, parasitism, concealment, and latency. Computer viruses spread rapidly and employ diverse attack methods. Generally, viruses cause harm by slowing down system operations, depleting memory resources, or inducing information leaks and system failures, resulting in significant losses.

Common Types and Attack Modes of Computer Viruses

Computer viruses can be categorized into several types based on their transmission media, each with distinct attack modes and levels of damage. Here's an overview of these common types:

1. Network Virus

A network virus spreads through the Internet and disrupts network components. The following are typical network viruses:

Ransomware, also known as ransomware virus, spreads through various means such as website attachments, USB flash drives, and spam emails. When activated, it encrypts user data, rendering it inaccessible until a ransom is paid for decryption. WannaCry is a notorious example, exploiting vulnerabilities in the Microsoft server message block (SMB) protocol to encrypt files and extort bitcoins, affecting numerous institutions worldwide.

Worms are self-replicating viruses that exploit system vulnerabilities, spreading automatically without human intervention. They can affect system performance, cause file modifications, and create unusual icons. Worms spread rapidly through vulnerabilities, network files, and emails. Panda Burning Incense, a notable worm virus, infected millions of computers in China in 2006 through web pages, USB drives, and network sharing, leading to system slowdowns and crashes.

2. File Infector Virus

A file infector virus infects the operating system's file system (e.g., COM, EXE, DOC, and SYS files) by embedding itself in computer source files. Once activated, the virus spreads rapidly as the infected files are accessed.

Macro viruses are a common type of file infector virus, particularly affecting Microsoft Office software. They target data and template files (e.g., word processor, data tables, and presentation files). When a Word document containing a macro virus is opened, the virus spreads to other users' documents. Infected files cannot be saved under different names; they can only be saved as templates. Due to the widespread use of Microsoft Office across various platforms, macro viruses can propagate extensively.

3. Boot Sector Virus

A boot sector virus infects the boot sector of floppy disks or the Master Boot Record (MBR) of hard disks, impacting the system during the booting process. As the system loads, the boot sector virus loads into memory and proceeds to infect other files.

An example of a boot sector virus is the Bouncing Ball virus, discovered in 1988. This virus spreads via floppy disks and is characterized by a bouncing ball animation displayed on the screen. While it causes minimal damage, it disrupts the proper functioning of infected computer programs. Despite its slow spread, it signifies a typical boot sector virus.

4. Multipartite Virus

A multipartite virus is a swiftly spreading type of virus that employs both file infectors and boot infectors to target the boot sector and executable files concurrently. This method of attack results in more extensive damage compared to other virus types.

Each type of virus poses unique challenges for detection and defense. Understanding their modes of operation is crucial for effective cybersecurity measures.

Features of Computer Viruses

Computer viruses share several features akin to biological viruses, including:

1. 1. Infectivity: Viruses can replicate and spread their code across computers via various means such as networks, wireless communication systems, and portable storage devices like USB flash drives. This enables them to infect multiple systems rapidly.

2. 2. Damage: Upon infiltration, viruses can cause harm to computer resources. This damage may manifest as reduced disk space, sluggish system performance, or severe consequences like data loss and system crashes.

3. 3. Parasitism: Viruses attach themselves to host programs and execute them when these programs run. Alternatively, they may remain dormant within the host program until triggered.

4. 4. Concealment: Viruses often exist as concealed code within programs or hidden files, making them challenging to detect, even through antivirus software.

5. 5. Latency: Some viruses remain dormant within a system for extended periods before becoming active. They initiate attacks only when specific triggering conditions are met.

These features collectively contribute to the disruptive and harmful nature of computer viruses, posing significant challenges to cybersecurity.

Symptoms of Computer Virus Infection

If your computer exhibits any of the following symptoms, it might be infected by a computer virus, necessitating immediate attention and remediation:

• Abnormal Startup or Sluggish Operation: The operating system may fail to start normally or operate unusually slowly.

• Frequent System Failures or Unexpected Restarts: The computer may experience frequent crashes or sudden restarts without apparent cause.

• Sudden Reduction in Disk Space: The available disk space may decrease significantly for no apparent reason.

• Program Errors or Crashes: Programs may report errors, fail to function correctly, or crash unexpectedly.

• Loss, Corruption, or Unexpected Creation of Files: Files may go missing, become corrupted, or new files may appear unexpectedly on the system.

• Uncontrolled External Devices: External devices such as the mouse or printer may exhibit abnormal behavior, such as automatic movement or malfunctioning.

• Unexplained Visual or Auditory Disturbances: Characters, images, or sounds may appear on the computer screen or play inexplicably without user initiation.

• Changes in File Attributes: The attributes such as date, time, and other properties of files may change unexpectedly.

If you observe any of these signs, it's essential to perform thorough antivirus scans and take appropriate measures to remove the virus and mitigate its impact on your system.

Countermeasures Against Computer Viruses

To effectively defend against computer viruses, it's essential to bolster both the system's defensive capabilities and our own security awareness. Here are some recommendations on how to mitigate the risks posed by computer viruses:

• Use Legitimate Software: Install genuine operating systems and software from reputable sources. Utilize trusted antivirus software and ensure it is regularly updated to detect and eliminate new threats.

• Keep Software Updated: Regularly update operating systems, applications, and antivirus software with the latest patches and security updates to address known vulnerabilities and strengthen overall security.

• 3. Exercise Caution Online: Be vigilant while browsing the internet and interacting with emails. Avoid clicking on suspicious links, downloading attachments from unknown sources, or visiting untrustworthy websites, as they may contain malware.

• 4. Enable Firewall Protection: Configure firewalls to actively monitor network traffic and detect potential threats. Utilize features that match virus signatures against an antivirus database to identify and block malicious files or generate alerts for further action.

By adopting a proactive approach to cybersecurity and implementing these countermeasures, organizations can effectively mitigate the threat posed by computer viruses and safeguard their systems and data against unauthorized access and malicious activity.