2 Comments on Viruses

A. A CCNA member wrote:

>I think my mac plus is sick! Every half hour or so the screen
>goes black and it reboots from my hard disk (as though I'd pressed
>restart from the desktop). So, if I don't save my work
>constantly, I inevitably lose data.

Perhaps your power supply is dying on you.. Maybe bring it in for servicing?

>My question is:

>Could my computer have caught a virus from CCNA?
>I haven't downloaded anything, but I've used e-mail and saved
>stuff on my drive from the buffer in my terminal software
>(Z-term). Could I have caught a virus this way?

The response:

No, No, and NO!!!!! ARGH! Ok, basic virus lesson is called for:

Viruses come in a few forms. Trojan Horses (pieces of code that destroy things, or programs), boot sector viruses (on some computer types), and file viruses. There are only a few ways to get one of those viruses - granted trojan horses are easier, but, are very rare.

One of the ways you can get infected is by running an infected program on a computer that is clean. Using a modem to log onto the CCNA is NOT a way you can EVER get a virus.

For some stupid reason, Hollywood has decided that all computers with modems should be able to get hacked into, and infected. That is simply NOT the case. A modem is ONLY an interpreter of audible 0's and 1's that the computer dumps to the serial port. And, unless you have a piece of software that SPECIFICALLY tells the modem to answer the phone and allow access to anyone in the world to your desktop (shells), it is impossible to have a hacker hack your computer JUST because you have a modem.

The ONLY thing your computer has is (most likely) a problem with the power supply. Also, if you are worried that your virus software is old, get an update.. Search on the  Internet!

David I Wolf

B. What are Viruses?

A virus is a piece of code that imbeds itself in an executable program and has 1 to 3 parts to it.

1. The virus code attempts to reproduce itself each time the program it is imbeded in is executed. Some viruses are quite sofisticated and will check to see if they are already imbeded .

2. The virus may have a timer of some sort and will check itself each time the code it is imbeded in is executed. This may be a certain number of executions, a date, a time, or some condition, etc..

3. The virus will execute some action when the timer reaches the trigger condition.  The action may be nothing at all, an irritaing message, a modification of a file, or a devistaing action such as deletion of a file, program or maybe the erasure of your hard drive.

There are messages going around on the Internet through email that warn people that they should watch for certain other messages which contain deadly viruses. The message goes on to tell you to send this warnng to all your friends and coworkers etc.. THIS IS A HOAX. The actual virus here is the email perliferation of the warning message. EMAIL MESSAGES CANNOT CONTAIN A VIURS.

An attachment to an email message can contain a virus if it is an executable file. This includes any .exe, .com, .bat, .dll and documents or files that contain macros.

If you have good Virus protection software on your machine and you use it to check any unknown diskettes or downloaded files from the Internet or via email, you need not worry about virues.

If you have comments, suggestions or concerns, please contact the CCNA Helpdesk

Last revised April 28 1998