difference between virus and worm?

what is difference between virus and worm?
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A virus is a file that cannot spread to other computers unless a infected file is copied and sent manualy to another computer were as a worm just does the opposite:

A worm is a wonderous creation that once in your machine usually copies itself and spreads using, irc, outlook or n e other applicable mailing unit, or as blaster just recently showed us using exploitations in ports on your computer... Usually a worm just uses ur computer as basically a server to spread as fast and silently as it can but others can have payloads attached to them, like a message box, or a deleting of certain files or shutdown of your computer, or just basically crashing your computer... Worms try to hide themselves as best they can(usually) but most of the time get caught really easily(look at blaster)

A virus once executed on your machine infects either com, exe or sys files or a combination of all three... Viruses are alot harder to get off your mmachine or even to get rid of... They have alot less spreading options then a worm does cuz viruses only infect files on ur machine... Usually viruses have a payload after infecting all files a certain number of files a certain time or date or just right after its infection takes place... These payloads differ but can be the same as the worms payloads or worse(i dont know wuts more worse then crashing sum1s machine but there must be much worse i guess)

Now this is pretty rare but sometimes there are combinations of the two.. A virus/worm combination can be EXTREMELY deadly. It can spread like wildfire through your machine and other machines upon which it can have payloads of crashing your computer or a network of computers while spreading to more computers.. There have been a select phew that do these tasks but there still are some out there and are very dangerous... Hope this helped a little bit

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she1Author Commented:

thanks all of you.
what do you mean payload?
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You can read it as "trouble"
Various virus's, worms and backdoor programs use something as a distraction while the payload(program) is being downloaded.

Several use a large jpeg picture as the distraction .
This was the way back orifice was placed onto a computer .
Basically today there is no distinction between a virus and a worm. Both infect a system, both carry out whatever commands they've been instructed to do, when they've been instructed to do it (payload) and both propogate to infect other systems via email (most common), operating system and application flaws, site coding and infected files.

A trojan horse, by nature, does not propogate. It is joined to a program, file or email attachment to allow some type of access to a target system from a remote system.

All three can mix and match, meaning a worm or virus can be programmed to download or drop a trojan horse (backdoor) into a system and a trojan horse can have a virus or worm dropper. An example of this was Blaster, a worm/virus which instructed systems to contact the writer's website in order to become available for access at a later time.

A payload can be a specific action the mal-ware may take at any given time. It can be initiated by a date, an action by the victim, whatever. EXAMPLE: CIH, or Chernobyl, would infect a system, attempt to propogate, delete hard drive contents and then attempt to flash the system BIOS after a period of time, making the system inoperable. It, and it's cousin Kriz, had a neat trick-they would infect files as they were being scanned by an antivirus. The only way to stop them was to download a neutralizing tool to stop the infection, then use the antivirus to remove them.

The next generation of worms/viruses (superworms) will have the ability to tailor themselves to a variety of tasks without intervention from the originating point, meaning they can actively interchange as many different parts to accomplish a variety of different tasks. They will be able to remove parts from themselves and download different and new additions at random. In fact, they will have the ability of changing themselves to the point that they no longer carry a recognized footprint and thus, become a new variant or the original. The potential is only limited by the writer's imagination and number of available downloads. This has been accomplished to some degree, but has not been initiated on a more complicated scale.

she1Author Commented:
what is  

"backdoor programs" ,?
  payload(program) ?
she1Author Commented:
what is  

"backdoor programs" ,?
  payload(program) ?
she1Author Commented:
thaks lot for all the help!
backdoor programs are also known as trojan horses, and this is really simplified, they are just programs that let another user(aka scum) into your machine while your on the internet. Back orifice is one such program. It started out as a useful tool to allow a tech to look into your computer while you were using it. The tech could then see what problems you have been complaining about first hand without having to stand over your shoulder. Once the program was taken over by the forces of no good it turned into something that allowed another to scan your files,change what you were doing at the moment(such as typing a letter), or just delete things.

a distraction would be where you get an email that has a large picture file attached to it. Usually it is a picture of a naked woman or some such(hench the distraction part). While you sloooowly downloaded this picture it also ran another executable placing a worm/virus/trojan on your machine.

payload is the code that is being loaded onto your computer(worm/virus/trojan).
she1Author Commented:

thanks lot , it is really helpful.

but I could not break the point now , I don't know why.
I have to give all the point to  jvuz

thanks for all of for great help to make this site a great place
to post
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