People used to ask specialists about what to do in order to don't get infected with email virus. The answer always was: do not open attachments. This was a good rule, until one crazy mind has created a virus that can be executed without opening attachments. With Nimda, this day came.

Summarizing to prevent dull details technician: to infect a computer, a virus needs to be executed. And for this is necessary open it (load in the memory and execute) the archive that contains its code. Until recently, if the user adopted the intransigent politics to never open attached files, the code that spreads the virus would never be executed and the user would be protected. Unhappyly this is not more truth.

At least for who it uses the programs of e-mail of the MS, Outlook or Outlook Express (first integrant of the package Office, second distributed with Windows). This because with intention to become them more attractive, the MS allowed that certain codes present on the messages can be executed when they are shown (that's how that "funny" musics when opening certain messages had appeared). A total superfluous function, evidently. But it has people that likes.

Result: it did not took a long time so one idiot has discovered a way to skirt the steps taken for the MS to guarantee that only secure codes were executed when showing messages. The result is the Nimda (Admin., abbreviation of Administrator., backwards). Worse thing is that if the Outlook or the Outlook Express is configured to keep open the auto visualization, it is not even necessary to open the message, is enough to select it: the simple exhibition in the auto visualization is enough to contaminate the machine.

The Nimda still explores other weaknesses of programs from MS, also one of its IIS (Internet Information Server, used for internet providers to manage its servers of Internet) that it allows to contaminate machines with a simple visit of internet pages in the Internet (exploring a known deficiency for web traversal exploit it can insert a malicious code in the page of such form that is enough to visit it to be contaminated - MS already developed the correction for the web traversal, but it is necessary that the internet provider install it to solve the problem) and can spread even in machines that use other programs of e-mail (but in this in case that it is necessary that the user opens the attached file, in general named Readme.Exe).

Nimda certainly is one of the viruses most dangerous already created and will give damages of billions of dollars (the attributed damages only the four virus, Melissa, Anna Kournikova, Love Bug and Code Red, assemble the four billion dollar ammount). And everyone in the Internet is now questioning how can be protected of this and other similar virus.

Well, to prevent the contamination is necessary that the internet provider that is hosting the page that you are going to visit use the IIS install the correction in its servers. The correction is available in the MS website for free download, therefore it does not have excuse not to install it. On the other hand, it is important to the user to bring up to date the archive of definition of virus of its antivirus: the problem caused by the Nimda was so great that all antivirus companies already does have the Nimda definitions on the update files (and if you already got infected, probably will find some utility to remove it). For those who does not use the Outlook, must continue grasped the practical rule of never open attachments.

Well, that's it. In our days nobody is safe anymore, even those who never transige the rules of never open annexes. The world is moving. E moving for worse...