Essay: Computer Viruses

What is a computer virus? A computer virus is typically a type of malware or self-replicating programs designed to spread from computer to computer wreaking havoc. Like human viruses that affect our body’s system, computer viruses come with symptoms that infect our computer’s system in miscellaneous of ways, some more severe than others.  Most, if not all of us, have experienced a computer virus in one way or another. Some virus simply slow down your computer, others can be more virulent. Computer viruses take all shapes and forms to try and infect a computer from a Trojan horse, to worms, to a Network virus, and come in many forms, like e-mails, portable devices, and websites containing malicious scripts. Computer viruses have a long history of infecting computer hardware and causing issues that make a personal tech’s life difficult. If you’ve ever wondered how dangerous viruses were like, then this might be an interesting read for you.
Trojan Horse
​Originating from an Ancient Greek story, the term “Trojan horse” symbolizes stealth and an ability to disguise itself. In the computer world, the most common type of virus is a Trojan horse. This virus unsuspiciously disguises itself as legitimist software in order to infect a computer with malware inside. Many users are tricked by some form of social manufacturing into loading and executing the virus onto their system. Once activated, a cyber-criminal, without user’s authorization, gains entrance to your backdoor system as well as sensitive data (i.e. passwords, banking information, etc.). In addition, attacker is given access to spy on you. Different Trojan viruses impact you differently, of course. One type of Trojan viruses is a Trojan-DDoS (Denial of Service). This targets web address by sending multiple requests from your computer and other infected computer thus crashing the web, consequentially leading to denial of service. Another notoriously known Trojan Virus is a Backdoor, where the virus uses remote control over the infected computer.  Meaning, the user with remote access can send, delete, and launching files or rebooting the system.
Nimda
​Surfacing in September of 2001, Nimda is a network virus that causes traffic slowdowns across the internet, spreading through four different methods. As a multi-vector worm, Nimda (“admin” spelled backwards) epidemically had spread through the Internet within 22 minutes, becoming the fastest computer virus at the time. Internet servers were the main targets of Nimda. Users containing a Microsoft Web Server or Internet Information Server (IIS) were denied of service as a result of this virus. Another way of getting this virus is through an e-mail attachment, which as a result, helped spread the virus across numerous servers much quicker. As previously stated, this does not destroy files or cause any harm to them but causes a DDOS attack. Once opened, the virus detects each IP address within a selected range, trying to exploit weaknesses that are known to be in attendance of computers with Microsoft’s Internet Information Server (IIS). A system showing IIS web server will read a message on the web page containing an embedded JavaScript that automatically executes, causing the same JavaScript code to spread to all web pages on that server thus creating a DDOS attack.
FAT Virus
A FAT Virus is a virus that attacks file allocated table (FAT), which is used to store information (i.e. available space, unusable space, file locations, etc.). Some Microsoft systems use this type of allocation to access storage data on their PC’s. The FAT Virus acts like a folder, keeping information on a hard drive and saving them. This virus attacks the FAT and making some files impossible to locate. Of course, FAT Viruses work in different ways. One way is when the FAT virus plants itself on a while so when the FAT tries accessing it; this triggers the virus thus causing havoc on the computer. Another way a FAT Virus works is attacking it directly. Some are designed to overwrite directories and files therefore losing information permanently. Sometimes, this virus can be so powerful, it can render the user’s computer making it unusable and forcing the user to format the hard drive.
Boot Sector Virus
A boot sector virus is a virus type that infects hard drives or floppy disk or even the Master Boot Record (MBR). A code runs when the system is booted from an infected disk or hard drive and once loaded, it will infect other drives or floppy disks when accessed on the infected computer. When an infected floppy disk or USB is inserted to a computer, the data will transfer when the VBR is read, then change the existing boot code. So the next the time a user tries to turn on their computer; the virus will be loaded instantly and run as part of the MBR or Master Boot Record. Because the MBR executes every time a computer is started, this type of virus is exceptionally dangerous.
Another way to get these viruses is through e-mail attachments if opened. This contains a code and then infects the computer and sends instructions to send out batches of e-mail to the users list of contacts. Although a boot sector virus may infect at a BIOS or minimal level, they still use DOS commands to spread to other hard drives or floppy disk. For this particular reason, the virus started to disappear after the appearance of Windows 95 and up.
Rootkit Virus
A Rootkit Virus is a type of software that intentionally disguises the fact that an operating system has been compromised by replacing vital executables within the system. Rootkits gets their name from the main administrator account in UNIX called “roots” and “kits”, which are software pieces that execute the program. Rootkits stealthily permit malware and viruses to hide as a necessary file that your antivirus software will fail to notice. Rootkits targeted UNIX operating system since they were originally used in the early 1990’s.
With the ability to hide almost any software, a rootkit can potentially hide file servers, botnets, keyloggers, and sometimes larger collections of files. Although, rootkits themselves are not destructive; they are basically used to conceal bots, worms and malware. A rootkit is installed when the attacker gains access to the root of the account by abusing or obtaining the passwords by cracking it. Rootkit viruses are infamously known to be difficult to detect as it may be able to subvert the software that is intended to find it.
Logic Bombs
A logic Bomb is a malware that triggers to an event, such as launching an application or when reaching a certain time or date. They can hide a specious code within a fake application and will be initiated whenever you launch the deceptive software.  An example of this is when cyber-criminals use spyware to secretly install a keylogger on your desktop. The keylogger can capture keystrokes such as your credentials to banks or social media when you visit a certain website. As a result, the keylogger obtains your information, and then can send them to a remote attacker. Furthermore, another way this is executed is when an employee works for an organization and implements the time bomb just in case he or she gets fired. Once fired, the time bomb will set off and destroy any files related to that person or even company data.
Macro Virus
A macro virus is when a computer virus infects a Microsoft Word or a similar application and causes a chain of events to be performed when the user starts the application and instantly triggers it. This virus can also be spread through e-mail. The most well-known example is the Melissa virus that occurred in 1999. The Melissa Virus was so powerful it had the potential to disable corporate in a short amount of time causing Microsoft to shut down incoming e-mails.
People fight back these viruses by installing effective anti-malware onto their systems. Rigorous anti-malware solutions such as Norton Anti-virus or AVG are some of the popular software user’s purchase to prevent these kinds of outbreaks on their computers. Keeping an updated anti-virus and frequently scanning can greatly decease of any virus epidemic happening. ​