How to handle boot sector viruses in floppy disk images?

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AmazingA
Posts: 4
Joined: Sat Sep 25, 2021 11:23 pm

How to handle boot sector viruses in floppy disk images?

Post by AmazingA »

Hi,

thank you for activating my forum account. I am a new member of this forum and have a question:

How do you handle a disk image that contains a boot sector virus?

I bought a couple of games from eBay. Unfortunately, some of them are infected with different boot sector viruses (e.g. Boot.1, Parity.1). When dumping and creating disk images out of them, my antivirus software informs me about the virus and put the disk image files directly into quarantine, so that I am not able to open the disk image files at all.
So, how do you handle those images? Is there a way of rescuing them and deleting the virus within the image file?

Thank you for your support.

With best regards
SomeGuy
Posts: 340
Joined: Wed Feb 18, 2015 8:18 pm

Re: How to handle boot sector viruses in floppy disk images?

Post by SomeGuy »

It used to be that virus scanners could be temporarily disabled or instructed to ignore certain files. I don't know if that is still possible, with how locked down newer "modern" computers are. If you can pry your file out of the grips of the virus scanner, then you can use an emulator with a DOS virus scanner to clean your decoded image files.

However, depending on what you are archiving, you might not even want the virus bits in the flux images. In that case, the best thing is simply to have a real DOS computer on hand with something like McAfee Vsheild for DOS. That is also handy for things like cleaning old personal information from program disks. Be aware that "modern" virus scanners also scan erased space in a disk image file. They will complain about any harmless traces found there. So in some cases, you may also need to use a tool like Norton WipeDisk for DOS to wipe the disk's erased space.
AmazingA
Posts: 4
Joined: Sat Sep 25, 2021 11:23 pm

Re: How to handle boot sector viruses in floppy disk images?

Post by AmazingA »

Thank you for your answer.

I have a few questions:

1. I guess, I can deactivate the virus scanner temporarily when creating the dump and image. However, can I infect my modern computer if the image file is saved on HD or when I open it in DOSBox?

2. Is there any free antivirus tool for DOSBox that you would recommend for this purpose?

3. Unfortunately, I have no DOS computer. Is there any possibility (for you Kryoflux experts out there 😉) to see from the tracks of the flux image that there is a virus and to delete the track/virus directly?

Thank you for your replys.
brightcaster
Posts: 465
Joined: Fri Nov 08, 2013 10:48 pm

Re: How to handle boot sector viruses in floppy disk images?

Post by brightcaster »

There have been so many different boot block viruses, that there isn't a general answer to the issue. In most cases you have to find out which virus has infected the floppy and after that search the internet for solutions to disinfect it...

Only a few weeks ago we had a similar topic:

viewtopic.php?p=16007&hilit=virus#p16007

The only DOS virus scanner I remember so far was from microsoft themselves:

https://www.youtube.com/watch?v=zwY1hBQByGM

David
SomeGuy
Posts: 340
Joined: Wed Feb 18, 2015 8:18 pm

Re: How to handle boot sector viruses in floppy disk images?

Post by SomeGuy »

As far as virus scanners go, I recommend McAffee Virus Scanner/Vshield for DOS. It does not usually leave extra garbage on disks like some other scanners, and it is very reliable about detecting and cleaning boot sector viruses. It was also distributed as uncrippled shareware, sou you can still find old copies floating around.

If the disk image is a standard 360k, 720k, 1.2mb or 1.44mb image, then you can run that from inside most emulators such as PCEm, PCE, 86Box, QEMU, and DOSBox, although DOSBox is usually a pain for handling disk images.

Now, if the images are copy protected, then it becomes much more complicated if you don't have a DOS computer.
AmazingA
Posts: 4
Joined: Sat Sep 25, 2021 11:23 pm

Re: How to handle boot sector viruses in floppy disk images?

Post by AmazingA »

Thank you guys for your answers!

I found McAfee 3.1x for DOS. I will give it a try.

With best regards
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