Quote from: nc50lc on October 07, 2019, 02:44:57 PM

Quote from: evgenia_volkova on October 07, 2019, 02:27:47 PM

When I was a victim it was advised to me to change the hard-disk and when asked they said changing OS is not the permanent fix. Can you explain which one is the right.

Probably because of those "low-level viruses" that can infect at binary level.
High-level format, aka: "format disk" or "delete partition" doesn't actually delete most of the files' traces, that's why it's possible to recover them using deleted file recovering tools.

Low-level format (zero-fill) should work in those cases, but that involves professional software tools.

There are malware which edits the firmware of the disk and then even full formatting will not remove the malware.
Therefore, advice for paranoid people is to replace the disk (perhaps flashing it will solve the problem, but who knows).
For even larger paranoiacs - replace (reflash) the motherboard. But in any case there is no guarantee that everything is taken into account.
One can only hope that such utilities will not be used for the mass user. Or use hardware/cold wallets.

One example:
https://www.wired.com/2015/02/nsa-firmware-hacking/

Quote

When a machine is infected with EquationDrug or GrayFish, the firmware flasher module gets deposited onto the system and reaches out to a command server to obtain payload code that it then flashes to the firmware, replacing the existing firmware with a malicious one.
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The only solution for victims is to trash their hard drive and start over with a new one.