Today the realm enters in merit of a new argument: the computer science security.
Who of you has not never felt to speak about Virus informed to us? In the last years virus like Melissa, love the You, Red Tails and others have caused damages for billions of dollars. New virus they are born every day and the industry of the virus becomes remunerativa is for the creators who for the "creator houses farmaceutiche"(i of Antivirus!).
The code malevolo said also to malware stretches to being classified based on the propagation mechanism, analyzes them in detail.

The Virus

The Virus classic from computer is a program or code that is reproduced automatically and that particular action executes in kind one.
Once the "Virus of the floppy disk" were classic, associated to they program inserted in a floppy one; today these obviously do not exist more but in compensation the Internet net abounds of releasable rows that carry with himself this disagreeable surprise.
One often thinks that the virus they are only one characteristic of Windows: this conviction is wrong, exists also virus for Unix; their spread is smaller why the Windows system much more is diffused and studied (and therefore more attacked).
Moreover the systems operated to you Unix based as Ubuntu decides of relative measures of protection to the authorization in order to execute determined azioni(the rights of root) the much stronger regarding the Windows systems therefore damage that determining virus can make in kind turn out limited.

The Worm

The worm they are much similar to the virus with the difference that in kind are not limited to infect a local system but propagano between the systems.
Here definition RFC 1135:
"a worm it is a program that operates in independent way; in order to maintain itself it consumes the resources of just the host from the inside of the same one and is in a position to propagare on the others blots of it one version of himself same completes and working ".

Today it is stretched to generalize the definition defining virus malware that they attack a local system and worm malware that they extend between the systems.
The worm in kind they stretch to take advantage of of the weaknesses of the software: as an example worm the Red Tails have infected Microsoft IIS by means of a overflow of the buffer.

The horses of Troy (Trojan)

The horses of Troy are "masked" programs from normal software that instead introduce behavior malevolo.
The name for who did not know drift to it from the Iliad: During the battle of Troy the inhabitants concurred that a Gift (exactly an enormous horse of wood) came delivered from the Greeks to the troiani as "ricompensa" for their Victoria; in truth that horse was stra full of soldiers and Troy came conquered.
The deceit of the Trojan in the simple case piu' consists in a fictitious name, in the more complex case in an entire program that it executes of the functions but that in truth it introduces of "features" hidden that in some way they damage our system.
The method in order to defend itself from the Trojan is simple: Not to never execute programs of which the origin is not known.

To defend itself from the Malware
The defense malware happens with two distinguished orders of software that probably will come examine to you in detail in post more happened to you: antivirus and the Firewalls.
The antivirus ones is a program that examines every rows of your enclosed computer the registries of system and the boot sector of your disc to the code search malevolo: what council is the Avg free antivirus that is gratis and it is brought up to date easy.
The firewall instead is a program that it avoids that malevoli programs (Trojan) succeed "to exit" from your malevoli system or that viceversa other software or hacker invades it from the outside: it is exactly a fire wall that blocks the access to your system.
The antivirus ones avg you can unload it free give:
http://download.html.it/software/vedi/1806/avg-antivirus-free-edition/ while the firewall in effects would go acquired (or one integrated in XP sp2 or Seen Win exists some)..
I personally Sygate council personal Firewall that is sturdy in the protection and does not weight down too much your system; in any case we will deal separatemente the argument firewall in one next analysis.