Question Can there be a virus in an empty storage device?

TheFlash1300

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Mar 15, 2022
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Can a virus be hidden in an empty store, and then infects my files when I paste them into the storage device?

For example, if I paste an infected file into my USB flash drive, can the virus be a type that hides in the USB, and becomes invisible and undetectable, meaning that if I delete the infected file, the virus will remain, but won't be visible in any way, and then will infect my other files when I paste them in the USB flash drive?
 

Colif

Win 11 Master
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Jun 12, 2015
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I don't think they can be undetectable. Hidden yes, but file system still knows they are there
I don't think they could infect other files placed on a USB

Any good AV will auto scan any USB device attached to PC so it shouldn't be a problem.

run a scan on PC if you concerned about files. Use this as a 2nd opinion scanner - https://www.hitmanpro.com/en-us
 
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Colif

Win 11 Master
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Jun 12, 2015
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If a virus hide itself, it the folder will be shown as empty, and it will show there are no files and no space is taken up. This is what I mean by empty store and hiden viruses. Can a virus hide itself like that?
it can conceal its size so it won't show in the total space used by folder.

All good AV will scan hidden files. Its mainly to hide them from user, lots of windows files are hidden

If you worried about a folder you copying to, you can right click it and scan it before putting anything there.
 

TheFlash1300

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Mar 15, 2022
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it can conceal its size so it won't show in the total space used by folder.

All good AV will scan hidden files. Its mainly to hide them from user, lots of windows files are hidden

If you worried about a folder you copying to, you can right click it and scan it before putting anything there.
I'm a worried that my USB flash drive is infected and there is still a hiden virus, despite the fact I deleted all files.

What anti-virus program can tell me whether or not there is a virus, with 100% certainty?
 
A couple things:
  • Viruses need to be executed before it can actually do anything. A virus sitting on a thumb drive will do absolutely nothing until something executes it. Since Microsoft disabled autorun on portable media, simply inserting a thumb disk will not execute anything anymore. So you have to execute the virus.
  • Formatting a drive doesn't remove any data per se. It wipes the partition data. As far as the OS is concerned, all of the space in the drive is available for use. But if you can do a low-level scan of the drive, you'll find that the data is still there. This is how basic file recovery programs work.
    • Even if the virus is still there in its entirety after a format, since the OS can't see it, it won't present it so you or anyone else can't execute it. Basically some other program would have to know it's there in the first place. And even then, the moment data is written to the drive, there's a good chance it'll corrupt the virus anyway because its data got overwritten.
There is a class of viruses known as boot sector viruses, but for removeable media, OSes won't run anything in the boot sector.
 

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