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What is Virus, Trojan Horse.. Does Firewall and Antivirus really keep us safe?

1) Malware= Malicious Software.

The word malware is a combination of two words “malicious” and “software”. It is a generic term used to describe all of the hostile and intrusive program codes including viruses, spyware, worms, Trojans, or anything that is designed to perform malicious operations on a computer.

The meanings of many of these words have changed over time. Some refer to how the malware infects your system while other words are used to describe what the malware does once it’s active in your machine.


When we’re trying to build better software to remove malware from your machine, the main things that we are interested in is how it got into your computer and how it is continuing to work. The malware will generally fit into one of the following categories.


Once malware is in your computer, it can do many things. Sometimes it’s only trying to replicate itself with no harm to anyone, other times it’s capable of doing very nasty things.

Adware – not truly malware and almost never delivered using one of the methods above. Adware is software that uses some form of advertising delivery system.

Sometimes the way that advertisements are delivered can be deceptive in that they track or reveal more information about you than you would like. Most of the time, you agree to the adware tracking you when you install the software that it comes with. Generally, it can be removed by uninstalling the software it was attached to.

Spyware – software that monitors your computer and reveals collected information to an interested party. This can be benign when it tracks what webpages you visit; or it can be incredibly invasive when it monitors everything you do with your mouse and keyboard.

Ransomware – lately a very popular way for Internet criminals to make money. This malware alters your system in such a way that you’re unable to get into it normally. It will then display some kind of screen that demands some form of payment to have the computer unlocked. Access to your computer is literally ransomed by the cyber-criminal.

Scareware – software that appears to be something legit (usually masquerading as some tool to help fix your computer) but when it runs it tells you that your system is either infected or broken in some way.

This message is generally delivered in a manner that is meant to frighten you into doing something. The software claims to be able to fix your problems if you pay them. Scareware is also referred to as “rogue” software – like rogue antivirus.

Some malware get into your computer and appear to do nothing at all. Such malware may have no obvious symptoms, but it has infected your computer along with a group of other computers, forming what is called a “botnet”.

This botnet can be directed by an Internet criminal to do any number of things including spam delivery and attacking Internet sites. Internet criminals don’t want to do anything direct that may be tracked back to them, so they employ botnets to do their dirty work for them.

Sometimes you’ll hear the term “rootkit” or “bootkit” used to describe a certain type of malware. Generally, this refers to methods that the malware uses to hide itself deep inside the inner workings of Windows so as to avoid detection.

You can mix and match these terms to describe just about any modern malware. Something like Tidserv/Alureon uses drive-by download to get into your system.

Once it’s in, it creates a bootkit so it starts before Windows even starts, and it creates a worm-like application that uses rootkit techniques to hide itself. Once it all starts up, it can act like spyware or it can hijack many Windows functions to do just about everything from putting advertising popups on your system to allowing someone to take remote control of your system.

For maximum protection, make sure your PC is protected with security software that can protect you against malware.

2) Virus:

Virus – this is a term that used to be generic. Any bad software used to be a virus; however, we use the term “malware” now. We use the word “virus” to describe a program that self-replicates after hooking itself onto something running in Windows.

Generally Corrupt Your System Files And Can Be A Reason Of [BSOD] Blue Screen of Death.

3) Worms:

A Worm is another kind of self-replicating program but generally doesn’t hook itself onto a Windows process. Worms generally are little programs that run in the background of your system.

Multiply Themselves within Short Period of Time Over A Network and in Large amount Can Slow down Your System.

4) Trojan:

Slows Down Your System and Open the Gates for Virus and Worms to Enter in Your system.

Trojan software that you thought was going to be one thing, but turns out to be something bad. Named for the fabled “Trojan Horse” that appeared to be a gift but in fact carried a dangerous payload.

Drive-by download – this is probably the most popular way to get something nasty into your computer. Most of the time, it comes from visiting a bad web page. That web page exploits a weakness in your browser and causes your system to become infected.

5) Cookies: Whenever Any Person Visit Any Cookie Enabled Website. For E.g.: E-commerce Or Any E-portal Etc.

Then Website Will Drop A Cookie (A File) Which Will Contain That Which Item Or Things Which You Saw In That Particular Website, So that, Next Time When You Visit That Particular Website So, That Next Time They Can Suggest You Recommendations And Things Which You Visited Last Time.

So, Cookies Help E-Commerce Websites to Present Their Items in Lot Better Way. –One of the Pros of the Cookies.

Cons- As there are pros of cookies so as there are cons of cookies and these are Third Party Cookies as Because Cookies Are Not Encrypted Form.

Third Party Cookies Are Dangerous Cookies Which Comes From Pop-Up Ads Or Click-Ads, These Ads Opens Up Additional 5to10 extra additional Tabs In Background, And When These Ads Place A Cookie Into Your System They Can Steal Your Credit-card Numbers, PIN Numbers, Etc.

Solution To All These Is A Total Security Antivirus Which Should Be A Pure License Version, Also You Can Disable Cookies In Browser Settings So That You Can Rid Of Them.

6) Firewall:

Also known as a ‘packet filter’. Basically, software which monitors network traffic and connection attempts into and out of a network or computer and determines whether or not to allow it to pass.

Depending on the sophistication, this can be limited to simple IP/port combinations or do full content-aware scans.

A firewall can be thought of as a screen or sieve that categorically strains out potentially harmful data.

Hardware Based and Software Based

Hardware Based: A Chip That Protects That Data Packet Which Has Been Send And Received From Your Desktop.

Software Based: Protects Your Desktop Whenever It’s Online, Blocks Unwanted Downloads and Files from Entering into Your Desktop.

Basically, It Blocks Unwanted Software and Files to run into your Desktop Whenever You Are Online or Offline – Doesn’t Matter!

Firewall and antivirus software are two fundamentally different and complementary kinds of security applications.

7) Antivirus:

A software which will find programs/files/software/etc that might compromise your computer, either by being executable or by exploiting a vulnerability in the program normally supposed to process them — Rootkits, Trojans, or other types of malware.

It detects these kinds of harmful programs that are already installed on your computer or about to be installed.

It can perform various protective measures (based on the security settings in the Anti-virus software) such as quarantine, permanent removal, fix, etc.,

It will also look for potentially harmful files that are downloaded from the internet or attached to an email and notifies/removes it to protect your computer.

NOTE: Antivirus software has to be updated frequently; each new strain of virus will likely have different signatures.

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