Below is a complete definitions about Viruses types and Spywares:
>> Normal Virus?
It might comes through an attachment, or infected files from different Medias, and it won’t be activated unless you run the infected file or attachment.
A spyware is software designed especially to gather your information and report them to someone else via Internet.
Usually spyware comes from the Internet by visiting a specific websites; it might come by your permission indirectly (like a website asking you to download an antivirus software for free or another software normally from a pop up window) or it might be downloaded without your consent.
They might affect your computer speed or your Internet connection speed, they might change your internet home page…etc.
Adware is software which displays advertisements on your computer.
Shows advertising banners and pop ups.
Attaches itself to the Internet browsers to display the advertisements.
It work like Spyware, hence taking information from your Internet Browsers and send them to another ones (through internet).
Slow down your Computer speed and your Internet connection speed.
>> Backdoor Trojan?
Backdoor Trojans are software allows someone to take control of another computer through the internet without permission.
The Backdoor Trojan used to be sent by the Hackers in order to connect their computers to the victim’s computer and to take a full control of the Victim’s one, like they can steal all your personal and confidential information, they can install or uninstall software on your PC, they can send emails from your own Windows, they can perform restarts or shutdowns to your Windows etc…
The problem with the Backdoor Trojan is whenever you connect to the internet it will try to connect to the Hacker’s computer, because once its created it adds it self to the Windows startup routine which means every time you open your PC , it will be initiated automatically.
From where those Backdoor Trojans come?
Backdoor Trojans are activated and installed on your system by you!! You would be wondering how come by me? Its real , because the only way to a virus to be activated and to start working on your computer is by double clicking the infected files… the infected files might be pictures, programs installation files, crack files, Macros, movie files and so on.
A Spam is an unsolicited commercial email.
This email normally comes into your inbox from different unknown email addresses and normally they have different subjects like (how to be rich?) or (learn languages in 1 day) or commercial subjects, sometimes they have a friendly way subjects like (Re: My reply to you.) or (Remember my advice…) or sometimes they come to you as you won a prize like (Congratulations you are the winner!! You’ve just won 1 million dollar…)
All of the above are simple examples about spam emails which usually either they want to promote a product, or they want to steal money from you…
How would they steal money?
Some of the spam email senders try to fool you that you have won million of dollars and will send you the money, or that they have a lot of money Inherited from their father in another country (which sometimes they give you a huge amount like 10 million dollars) and they need your assistant to transfer their money to their account in their country, and they will send you a percentage of that money as a commission for your transaction, but they tell you they need you to send them the money transfer transaction charges in advance (which sometimes they ask for about 200$ or more) to their address in order to transfer your commission, so once you send them the money you will never hear from them anymore (so don’t let anyone fool you)
>> Trojan horses?
Are programs that perform harmful activities in a legitimate face.
Trojan files are so dangerous because they seems to be normal software when you run them while they are performing another activities in the background like stealing passwords or confidential information or even to make problems to your system, basically those Trojans come via the email, or by using the crack files.
>> Boot Sector Virus?
Boot Sector Viruses are software that starts spreading by changing the program which leads your PC to startup.
The boot sector is where the computer looks into it in order to start initiating the hardware and then to complete loading the Windows into the computer memory.
The Boot sector virus will replace the small program in the boot sector with the infected one in order to be activated every time you start your PC, this virus normally comes from a floppy disk, flash memory, CD/DVD or the Internet.
>> Browser Hijacker?
The Browser Hijackers change your default home and/or search page into another one.
Some websites use a special software once you visit them they change the settings of your own Internet browser in order to force you to visit their websites, even sometimes you might don’t have the ability to remove them easily, and sometimes you have no other option but to reformat your Operating System.
What benefits they would have?
Good question, for webmasters the number of visitors to a website is so important in order to get higher page ranking over the internet and to be displayed in the first page of the search engines like Google or Yahoo.
Cookies are files downloaded on your Computer enabling websites to remember your information and details.
Cookies are designed to be helpful for the users, and an example on how they designed to be like that is when you enter you information in a registration page, the cookies stores these information on your Computer so next time if you use another registration form you don’t have to type the information again cause they will already show up.
But they have their disadvantages as well, because they are stored on your Computer without your consent, and sometimes confidential information might be stolen because of them.
>> Document Viruses?
Represented by Macro Viruses.
The macros which are imbedded within a Microsoft Excel or Word files or in a spread sheet can contain a virus as a command lines scripts which will start running once you click on the infected macro.
This type of Viruses can spread so fast , cause once you run it for the first time it will infect your computer and may spread over a network to another PCs, this virus would change the settings of the document or may damage it.
>> Email Viruses?
Email Virus is a self spread virus via email.
The purpose of those viruses is to increase the traffic on the emailserver, or to infect your computer with malicious virus or to steal data and personal information from your own computer.
The Email Viruses usually come from the email attachments, or the email it self by opening the email or reading it, that’s why we always say if you receive any un-trusted emails or from unknown addresses don’t you even think about opening them, just delete them directly.
Worms are software that recreates copies of themselves and spread through the internet connection.
The worm virus uses the security weakness on the Computers within a local network or an internet connection to spread, this virus could lead your system behavior for instability, it can slow down your internet connection or to be used as backdoor viruses (which allow Hackers accessing your PC), it might cause your personal or system files to be damaged or might cause a System crash.
For that reason, you have to update your Windows as long as there is an update from Microsoft, because periodically they are enhancing and updating the security of the Operating System.
>> Mouse Trapping?
A Mouse trap is a virus that prevents you from leaving a specific website.
It is originally comes from malicious internet websites which infect your computer with the virus, these types of viruses uses the java script on your browser so disabling the java script will somehow protect you from infecting with such viruses but at the same time it will affect the look and feel of many websites.
>> Parasitic Viruses?
A Parasitic Virus spread by attaching itself to a file or a program file.
So in this case every time you run an infected file you run the virus as well, and the Windows gave already the same rights and permissions of the original file to the virus because it treats them as the same file, the virus can run into the memory and perform the operation for what it was designed for.
Phishing is the use of faked emails or websites to trick you and lead you to supply personal or confidential information and stealing them.
Those faked sites or emails originally sends by Hackers to collect confidential information like passwords, credit card information etc… so be careful and pay attention to any email that might come to you specially when it seems to be like a genuine source, like from a famous organization or from a bank etc … sometimes even you would open a website which it might look like exactly as the genuine one while it is only a replica of it.
For instance, an email comes to you (seems to be from the same email service provider of you own like hotmail) once you open it you will be redirected to a page exactly as if it was from the same genuine oranization telling you that you have signed out and we are sorry for that so to sign in back please enter your information (“which are user name and password”), once you enter the information and click on sign in your user name and password will be emailed to the Hacker’s email.
For your safety don’t click on any link sent by an email in case it seems to be from a genuine source, instead write the original address in the browser address bar and access it from there or use the favorite’s bookmarks to open such websites, and when purchasing from the internet always use PayPal and don’t use your own credit card number.
Ransom-ware is software that denies you from getting access to your files until you pay a ransom.
This virus is working as a blackmailer, once it infect your files it will encrypt them with an unknown passwords and asks you to pay an amount of money through money transfer companies or your Computer will be corrupted, and usually this type of files are faked and won’t do anything.
Is software that hides malicious programs or processes running on a Computer.
This virus comes with another malicious software or program like backdoor virus or Internet worm …etc, in order to hide their process while infecting the Computer or even during their work.
Some antivirus programs cannot detect this rootkit virus, so it is considered as harmful software because it might affect the System by letting other viruses or Hacker’s torjans run without your consent or knowledge which might cause System instability or your confidential information to be at risk.