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| Figure 1:Virus Checker's Options |
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One oft heard complaint among Amiga users is the lack of developers. In one area, however, this is occasion for celebration- the Amiga has far fewer worries in regards to viruses than the PC or Mac.
Unfortunately, there are enough miscreants with enough talent and too little regard for their fellow Amiga owners that the issue cannot be ignored. Fortunately, there are several excellent Amiga anti-virus programs, which, with a little care, should keep your Amiga healthy and happy.
A computer virus is a program written to do a number of specific things. The first goal is to be able to replicate itself, and spread to other files and ultimately, to other computers. This is accomplished by hijacking innocent programs, and inserting the virus code somewhere in this hapless program. When the newly infected program is run, the virus is also activated, and can infect other files. There are generally two ways to spread a virus, via a boot block on a floppy disk, or via infecting programs. When you boot your Amiga from a floppy disk, a small program on the boot block is loaded and run. A virus can modify this boot code so that your Amiga is infected when you boot with the floppy.
As floppy disks become less widely distributed, file viruses have become more prevalent. Only executable files can actually spread the virus. If your system has been infected with a virus, that virus can change, corrupt or delete your datafiles, but your Amiga cannot catch a virus from a datafile.
Once your system is infected with a virus, it can be difficult to eradicate. This is particularly true of situations where the virus is a sleeper or time bomb. These viruses infect your system, but do not announce themselves right away. They bide their time, waiting for a specific amount of time, a date, or perhaps some future event. During this period, unaware of being infected, often people will back up their hard drives, including the virus, resulting in possible reinfection should any files be restored from that backup.
Most viruses have other agendas, aside from the basic act of infection and replication. Some viruses merely display "gotcha" messages proclaiming the cleverness of their inventor, some are of a far more destructive bent, and can crash your Amiga, delete or corrupt files, or even format your hard drive.
Recently, several new developments have lead to much confusion about computer viruses. There is a virus capable of infecting Microsoft Word Macros. You might not think of a macro as an executable program, but in actuality it is. Depending on the sophistication of the Macro language, there is some room for mischief. So far as I know, there are no macro viruses on the Amiga, and no, that is not a call to action!
You may also have heard of the infamous penpal email virus- you download an email, and just by reading it, your computer contracts a virus. This is a hoax! You cannot get a virus from reading an email message...and neither can your computer! Only if that message has a program attached to it, and you run the attached program could your system be infected.
As in biological viruses, the best cure is prevention. A little prudence and forethought will go a long way toward keeping your Amiga safe from infection.
1. Get yourself an Antivirus program, and use it! There are several, three of which I cover later in this article. Look in the util/virus directory of Aminet for a plethora of anti-virus programs and information. Make sure you get an antivirus program either directly from aminet or the author. There have been cases where bogus versions of antivirus programs were themselves infected with a virus! Modern antivirus programs generally can check themselves when they are run, to prevent this nasty trick. Be sure and check periodically for new versions of the anti-virus program, to protect yourself from new viruses. Unfortunately, anti-virus prog
2. Be careful where you get files. Your best bet for Shareware/freeware is Aminet, or a commercial outfit. These are generally conscientious about viruses, and do all in their power to keep their offerings virus free. You can also trust most Amiga developers, whether shareware or commercial, many of whom provide their programs via BBS or the World Wide Web. Be wary of unsolicited programs sent to you either via email or via floppy, especially if you don't know the sender.
3. If you do get a virus, remember that it may have infected any floppy disks or backups you may have made.
4. Don't panic! After all the press computer viruses have received, the first thought for many people when something unexpected happens on a computer is, "Oh no, a virus!" Not to slight the real danger of computer viruses, or imply that the press is uniformed or sensationalist, but in over ten years, I have only seen one Amiga virus, and the anti-virus program I was using at the time, Steve Tibbett's VirusX, spared me any damage it might have caused. So take the above precautions, but don't lose sleep worrying about it. In fact, we can all have warm and fuzzy thoughts about our Amigas, knowing we face less danger than the far more inviting target of the PC or Mac.
The best bet to prevent infection from viruses is to run an anti-virus program. The following programs can scan for both file and boot block viruses, and everyone should have at least one of these programs on their Amiga.
Virus Checker, John Veldthuis, is a widely used anti-virus program for the Amiga. This program checks both file and boot block viruses. Features support normal executable programs and many compressed file formats. The registered version can even detect a virus in an LHA archive. In order to deter bogus versions from being distributed, the archive is 'signed' using PGP (Pretty Good Privacy). For those unfamiliar with PGP, Dr. Michael Tobin wrote an excellent introduction to the encryption/authentication program in the January 1997 issue of Amazing Computing. See Figure 1 for a screen shot of Virus Checker's options.
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| Figure 1:Virus Checker's Options |
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VirusZ, by George H. Farmann, is a verteran in the Amiga anti-virus wars. VirusZ detects file and boot block viruses, and in addition to standard background virus checking, VirusZ has a number of useful utilities, including Bootblock lab, for examining and modifying a floppy disk's boot block, a disk sector checker, and memory and vector checking. VirusZ supports XFDMaster and unpack.ibrary to check compressed files for viruses. See Figure 2.
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| Figure 2:VirusZ |
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Finally, XTruder, by Martin Wulffeld, is a powerful and flexible anti-virus program. Xtruder features a file check interface, report creation and checking facilities, virus information checking LHA,LZX, unpack.library, and XFDmaster support for archive checking, as well as DMS archive boot block checking, font and screen mode sensitive GUI. Martin also uses PGP for program authentication. Figure 3 shows Xtruder.
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| Figure 3:Extruder |
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