Viruses

A computer virus is a computer program that can copy itself and infect a computer without the permission or knowledge of the owner. The term “virus” is also commonly but erroneously used to refer to other types of adware, malware and spyware programs that do not have the reproductive ability. A true virus can only spread from one computer to another (in some form of executable code) when its host is taken to the target computer; for instance, the user sent it over a network or via e-mail, or carried it on a removable medium such as a floppy disk, CD, DVD, or USB drive.

The term “computer virus” is sometimes used as a catch-all phrase to include all types of malware. Malware includes computer viruses, worms, trojan horses, most rootkits, spyware, dishonest adware, crimeware, and other malicious and unwanted software, including true viruses. Viruses are sometimes confused with computer worms and Trojan horses, which are technically different. Viruses can increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by another computer.

Every human knows biological viruses can negatively impact or affect their health, but not all truly appreciate or understand the mechanics of a computer virus and how it can directly and indirectly impact their livelihoods. Thanks to the loose translation being used by persons on and off the web, many assume the term virus, as it relates to viral transgressions, encompasses all malware types and behaviors. Well, this is not true at all, since computer viruses have their own distinct characteristics. A better generalization or translation could be found in the term ‘infection’, describing the  effects or resulting condition on intellectual properties invaded by any malware form. 

What makes a computer virus different from other malware types?

Unlike a Trojan or rootkit, a virus and a computer worm both have the ability to self-replicate and can therefore spread must faster than other malware types. The separator or difference, however, lies in the manner in which self-replication and thus propagation is achieved. While worms can travel and spread independently via a network connection, viruses are dependent on a host and attach to files (mainly executables) that require activation, i.e. clicking and file sharing by victims, to attack or infect and possibly spread. Therefore, a virus can damage legitimate programs by overwriting them and thus destabilize your system, or at a minimum, render different applications or programs unusable. 

Other behaviors:

There are several types of viruses: polymorphic, boot sector, metamorphic, macro, CSS, etc., all driven by the language in which they are written. Also dependent on the malware maker (i.e. malicious programmer) is how many components will be infused into his or her infectious program. Most malicious programs, if not all, have the ability to load their programs in memory so they run every time the operating system is started. Most malicious programs, including viruses, are usually programmed to reconfigure the infected system to not only set up the attack, but guard against removal efforts by the victim or its antivirus tools. Some steps that will be taken involve:

• Running an algorithm to find and destroy files updating or running antivirus or security programs, i.e. Windows automatic updates
• Disabling administrative controls, such as Task Manager, System Restore or even Safe Mode
• Hijacking the browser and rerouting traffic for the following purposes:
  • Keep victim from visiting helpful malware removal websites
  • Force visits to websites, i.e. arbitrary search engines, to encourage click fraud
  • Force visits to malicious websites promoting sale of a rogue security program
  • Force visits to compromised websites housing a Trojan downloader
• Adding registry entries that help bypass the firewall, rendering it useless

Many attacks employ the aid of other malware types, i.e. rootkit, to help bury or masks malicious activity. Malicious files will be made to read the same as legitimate operating system files and legitimate running processes hooked to circumvent malicious activity. 

The point of entry:

Like a biological virus, a computer virus is prone to attack vulnerable hosts. If your system is without stealth antimalware protection and is housing software or programming in need of patch, using the Internet will be cyber-suicide. Viruses can be hidden behind a link or attachment wrapped in a cleverly written or spoofed email communication or planted on the friendly grounds of social networks. Malware, in general, is often cloaked inside the download of freeware or shareware or dropped by a Trojan downloader camped out on a compromised website you visited. 

A true safety guard and net is an antimalware program that uses a mix of scanning techniques to weed out malicious code hidden in adware or other free tools, or decoys, i.e. fake Adobe Flash updates, Windows security alerts or video codec components, to pinpoint a few common traps used to trick PC users into clicking and self-infecting their systems. 

Most viruses (if not all) are without an interface, therefore, alert is dependent either on a stealth antimalware guard or the victim paying close attention to weird system behaviors. If your system is enduring any of the following, you really need to grab hold of a trusting scanning tool to investigate.

• Suddenly running slow, freezing up or crawling
• Browser settings reversed and allowing a floodgate of pop-up advertisements, whether online or offline
• Intermittent reroutes to unwanted URLs
• Alt-delete not behaving as intended and thus forcing hard boots

The malware maker or malicious programmer will determine how many payloads the malicious program will attempt. At a minimum, data stored in the browser cache or on the hard drive will be stolen and a backdoor opened to allow a hacker remote access. Other threats may involve installation of a keylogger to record keystrokes being entered into online banking sessions. Therefore, it is crucial to remain vigilant and react to any system abnormalities by use of a professional antimalware tool able to counter obfuscation tricks and rootkit technology.