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E-mail Viruses

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There are many hoax warnings that go round the Internet, clogging up mail servers and other networks, because some people like to make dumb jokes. Innocent people then forward these "warnings" in good faith, causing others to do the same. The information given here is designed to dispel some of the fears created by these messages. Please read the disclaimer.

1. Don't go to a Certain Page/Site
These warnings tend to have the following message:
"Beware! if someone named asks you to check out his page. DO NOT! IT is at http://www.something.com/somewhere/" (or similar).
I don't really know why people write this kind of thing but. it's complete rubbish. Web pages (as in normal HTML code), cannot hurt your computer in any way. However, web pages can contain components such as JAVA applets and ActiveX controls. Both of these technologies are quite capable of destroying your hard disk, but fortunately, not without you authorizing them to. Any of these controls will have to be what is known as signed by the author, i.e. the author will have to have paid a company such as Verisign to check up on his identity. That way you can know that the author is who he says he is. Browsers such as Internet Explorer (if they are on their default security setting), will not even run unsigned controls. You can set the security options to ask you whether you want to run the controls. My advice is that unless you know what you're doing, don't bother, as you won't need to. The golden rule is not to run any unsigned content. The other golden rule is to never allow a control to access any of the privileged properties of your computer. Privileged properties are things like reading and writing files on your hard disk, running executable files on your computer, and so on. A control must be signed to even ask for these privileges. When asked, unless you really trust the company whose control it is, don't grant the privilege. This applies to both JAVA applets and ActiveX controls. Another technology that can potentially cause problems is JavaScript. This is by no means as powerful as JAVA or ActiveX, but is more widely used for things like simple animations in web pages. Without privileges, it cannot damages your computer in any way: the worst it can do is make hundreds of windows appear, which will eventually crash your computer. Simply restart (reboot), and you'll be fine. These are annoying things, known as JavaScript bombs. They can also be placed in e-mails, but only advanced e-mail programmes can read them anyway (e.g. Outlook Express, Netscape Messenger), and you can easily turn off JavaScript from executing in e-mails from the security options within the programme. Even if you don't, the worst that can happen is that you have to restart. To get rid of such an e-mail, just delete it. It will not damage your computer.
In conclusion then, a web page cannot hurt your computer without it having signed controls, and only then if you authorize it to have privileged access (so don't!).

2. E-mails with Certain Subject Lines
These tend to have the following format:
" If you get an e-mail titled: "Win a Holiday" DO NOT open it. Delete it immediately. Microsoft just announced yesterday. It is a malicious virus that WILL ERASE YOUR HARD DRIVE. At this time there is no remedy. Forward this to everyone IMMEDIATELY!!"
(The favourite ones are "Win a Holiday" and "Penpals", but there are others).
One thing to be noted right away is that Microsoft never issues warnings like this. The only thing that they might issue a warning about would be if someone was sending out an e-mail that claimed to be from Microsoft, which is extremely rare. Secondly, anything saying that it will "Erase your hard drive" tends to be fake. Why? Because that's the standard thing that goes into all hoaxes. Likewise, "it will attach itself to all the chips in your computer which will malfunction.", and "your computer will burn up" are also fakes. Oh, and they always say that there's "no remedy", it makes it much more fun. The main point is that e-mails (as in messages), cannot hurt your computer if you open them. It is absolutely impossible for a text message to infect your computer, as it cannot contain anything except text. HTML messages, i.e. those which have different fonts and colours in them, have the same risks as web pages (see above). Therefore, the only possible way that your computer can become seriously infected is by you opening an attached file that comes with an e-mail. The golden rule is simply never to open any attached files that come with any e-mail. Simple. Whatever the message says the file is, don't open it unless you know exactly what it's meant to be, and you trust the person who sent it to you. If you're unsure, don't open it, and reply to the sender, asking what it is. Note that this is a wise idea, as many viruses manage to attach themselves to all of the sender's outgoing messages (if their computer is infected), and therefore you might get a normal message with a file attached, which the sender didn't actually attach. Be especially cautious about opening attached files that come with blank messages (although these may have a subject line), from someone you trust. This is likely to be the a virus on their computer propagating (spreading) itself. If you do want to open an attached file, it's a good idea to save it on your hard disk (don't open it!), and then scan it with an up to date virus checker. In conclusion, you can open any message you want without fear or permanent damage to your computer, but don't touch attached files.

3. Files Attached to E-mails
Many effective hoax e-mails involve these. The message tells you not to open any attached file with a certain name, as it will do something nasty to your computer. The problem with this is that in theory it's quite true, and you should be very careful with attached files. However, you can figure out quite easily if a virus warning is true, by the way it is written. Normally hoaxes are written so that they sound absolutely dire: it sounds much better and makes people scared enough to forward them.
" After it is activated,, the PC cannot boot up at all. It goes very slow. It destroys your hard disk. The filename is CELLSAVER.EXE"
The above is one I received about a screensaver. All hoaxes will say "it destroys your hard disk". In theory it is of course possible, but if we're talking about a real warning then one would expect a somewhat more technically specific approach. Also, just read the text carefully: "The PC cannot boot up at all." Fair enough, so that means that the machine is unusable. However, then we find that "It goes very slow". Does this mean that we can now boot up?! Do a bit of logical analysis on the messages that you get and you can discard many of them because they don't make sense.

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General Advice on Viruses

Macro Viruses

E-mail Viruses (& Hoaxes)

Notes & Disclaimer