A computer virus is just an executable program that instruct our computer to do something that we don’t want it to do. It makes our computer unstable and abnormal.
They are generally harmful in nature and are capable of reproducing and spreading with or without human actions (depending on their type).
Virus stands for Vital Information Resource Under Siege.
Effects and Abilities:
Computer viruses can corrupt data, delete data, steal confidential data, play pranks, disable hardware , use our computer to attack websites (Dos attack), damage our credibility and may cause us embarrassment.
Objectives of creating computer viruses:
To cripple and control our computer or its network, to steal sensitive information (credit card number, password, personal details etc.), to generate money (by making you point to specific webpage or adv.), to test anti-virus capability, to prove ones skill, for revenge or just for fun and thrill.
How computer viruses are created?
As mentioned earlier viruses are just a program so they can be created with any language that works on targeted system. Computer languages like ANSI COBOL, C/C++, pascal, VBA (visual basic for applications), unix shell script, java-script etc. can be used to create deadliest viruses.
Symptoms of computer virus attack:
To know that you are being or already been affected by a computer virus is to observe the symptoms like computer will work slowly than usual, computer no longer boots up (start), screen flickers sometimes, pc speaker beeps periodically, system crashes for no reason, files/directories sometimes disappear, denial of service (DoS) etc.
Categories of Computer Virus:
Computer viruses can be broadly divided into four categories stealth, polymorphic, companion and armored.
Stealth virus is a computer virus that uses various mechanisms to avoid detection by anti-virus software.
Polymorphic includes a scrambled virus body and a decryption routine that first gains control of the computer, then decrypts the virus body.
Companion is one that, instead of modifying an existing file, creates a new program which (unknown to the user) is executed instead of the intended program. On exit, the new program executes the original program so that things appear normal.
Armored virus are designed to stop anti-virus researchers from examining its code by using various methods to make tracing and disassembling difficult.
Types of Computer Viruses:
Viruses can be categories into different types but mainly into Trojan horse, worm, macro, Boot sector Viruses, Root-kit Viruses, Multipartite Viruses, E-mail viruses, Memory Resident Viruses and Logic Bombs/Time Bombs.
Protection against Computer Virus:
- Use a genuine licensed operating system with latest security patches installed. Genuine OS will give you more security and support that pirated one. If you have a OS like window-7 original than you’ll get free anti-virus and firewall installed.
- Use a latest anti-virus (including spyware, malware, key logger, adware protection). Some good anti-viruses available in market are quick heal, Norton, avg, avast etc. most of them comes with internet and email security too. List of best Antivirus Software for Windows.
- Install a personal firewall. Today when we are totally depended on computers we must need a firewall protection for unauthorized access to our system. A good example of personal firewall is zone alarm or you may use comodo firewall.
- Update your OS, Anti-virus and firewall regularly. New viruses are created daily and to have protection against them use latest software’s.
- Never open or download unknown files with extension like .exe, .com, .bat, .vbs, .res, .js or any other executables from email or internet and if necessary then scan them with antivirus before running.
- Always have back-ups of your data on some external devices like cd-dvd, pen-drive or external HD. In case you are affected by a virus you can retrieve your data easily and can take further actions.
If you are already affected by a computer virus then you must run anti-virus scan in safe mode. As in safe mode only vital programs of OS runs and almost all viruses remain inactive and you can remove 99.9 % of viruses successfully.
So what you think about computer viruses and what precautions you are taking? did they ever attacked your system? Please Share!