COMPUTER VIRUS

Definition of Computer Virus

• A computer virus is a small software program that interferes with computer operation and spreads from one computer to another.
• A virus is a self-replicating program that copies itself and that can infect other programs by modifying them or their environment such that a call to an infected program implies a call to a virus.

Brief History of Computer Virus

Robert Thomas, an engineer at BBN Technologies developed the first known computer virus in the year 1971. The first virus was christened the “Creeper” virus, and the experimental program carried out by Thomas infected mainframes on ARPANET (Advanced Research Projects Agency Network). The teletype message displayed on the screens read, “I’m the creeper: Catch me if you can.” But the original wild computer virus, probably the first one to be tracked down in the history of computer viruses was “Elk Cloner.” The Elk Cloner infected Apple II operating systems through floppy disks. The message displayed on infected Apple Computers was a humorous one. The virus was developed by Richard Skrenta, a teenager in the year 1982. It was Fred Cohen, who coined the term “computer virus” and it was after a year in 1983. The term came into being when he attempted to write an academic paper titled “Computer Viruses – Theory and Experiments” detailing the malicious programs in his work.

Types of Computer Viruses

1. Boot Sector Virus: This type of virus infects the master boot record. It is challenging and a complex task to remove this virus and often requires the system to be formatted. Mostly it spreads through removable media.
2. Direct Action Virus: This is also called a non-resident virus; when executed, it scans the disks for targets, infects them, and then exits (i.e., it does not remain in the memory after it is done executing).
3. Resident Virus: A resident virus installs itself as part of the operating system when executed, after which it remains in the RAM from the time the computer is booted up to when it is shut down.
4. Multipartite Virus: This type of virus spreads in multiple ways. It infects both the boot sector and executable files at the same time.
5. Polymorphic Virus: These types of viruses are difficult to identify with a traditional anti-virus program. This is because polymorphic viruses alter their signature pattern whenever they replicate.
6. Overwrite Virus: This type of virus deletes all the files that it infects. The only possible mechanism to remove is to delete the infected files, and the end-user has to lose all the contents in it. Identifying the overwrite virus is difficult as it spreads through emails.
7. Space filler Virus: This is also called “Cavity Viruses.” This is called so as they fill up the empty spaces between the codes and hence do not cause any damage to the file.
8. Macro viruses: As the name suggests, macro viruses particularly target macro language commands in applications like Microsoft Word. The same is implied on other programs too.

Examples of Viruses

1. Trojan horse virus
2. Sleeper
3. Logic bomb Alabama virus
4. Christmas virus
5. Jerusalem virus
6. Resident virus
7. Nonresident virus
8. Code Red
9. I love you
10. Creeper virus
11. Stone
12. November 17

Sources of Virus

These are the means through which viruses could be spread from one system to the other.
They include:

1. Infected memory devices (e.g., USB drives, external hard drives)
2. E-mail attachments (especially suspicious or unexpected ones)
3. Internet downloads (e.g., software, media files from untrusted sources)
4. Computer networks (through shared drives or network vulnerabilities)
5. Illegal duplication of software/cracked software
6. Unsecured websites (malicious sites or compromised legitimate sites)
7. Malicious Websites (Drive-by Downloads)
8. Malvertising (malicious advertisements)
9. Outdated operating systems or applications)
10. Social Media Scams (malicious links or files shared on social platforms)
11. Unsecured Public Wi-Fi Networks

Virus Warning Signs

Some of the virus warning signs are listed below:

1. Slowing down response time
2. Wandering cursor across the screen
3. Incomplete saving of files
4. Corruption of the system set-up instruction
5. The appearance of strange characters
6. Insufficient memory space in a hard disk when you have enough memory space
7. Frequent system crash
8. Unfamiliar applications or processes appearing on the background

Virus Detection (Anti-Virus)

Anti-viruses are also written programs by software developers to stop and curb the spread of the virus in a system. Antivirus software is a type of utility software used for scanning and removing viruses from your computer. Once an anti-virus is installed on a system, it will be hard for a virus to enter the system except if the antivirus is outdated. All antivirus can be updated on the internet.

Examples of Antivirus Programs

1. Norton Anti-virus
2. McAfee
3. AVG
4. Bitdefender
5. Panda Dome
6. Trend Micro
7. Malwarebytes
8. Avira Prime
9. Intego
10. TotalAV
11. Bitdefender Total Security
12. Dr Solomon’s Tool Kit
13. Penicillin
14. Avast
15. Windows Defender
16. Kaspersky

Computer Virus Preventive Measures

1. Install a good Computer Antivirus.
2. Timely update of the operating system.
3. Timely update of antivirus software.
4. Installation of only trusted or licensed software.
5. Exercise care when you browse the internet.
6. Use a firewall.
7. Be cautious with public Wi-Fi.
8. Educate yourself and others on common scam tactics, phishing attempts, and social engineering tricks.
9. Isolate infected system(s) immediately.
10. Enable pop-up blockers in your web browser.
11. Back up your files and data regularly.
12. Be wary of email attachments and links from unknown or suspicious sources.
13. Use strong, unique passwords and Multi-Factor Authentication (MFA) for your online accounts.
14. Disable Autorun for external devices (like USB drives).