Are there viruses/spyware that cannot be detected?

Question

Malware

Are there viruses/spyware that cannot be detected? No way.

Answer 1

No. For any software, there is at least one person who knows how to detect it - this is its author :)
But I think you meant - "is there software that I cannot detect on my computer?". Then the answer is yes, there is. There are many places where it can be placed, some of them very technically difficult, but possible. Bookmarks can be set: -
in application software
- in OS
- in UEFI/BIOS
- in processor microcode
- in the form of a chip on the motherboard
it will be installed - if you are not Navalny, no one will warm your head how to bookmark you in the BIOS :)

Answer 2

Of course they do.
This is called "software bookmarks".
They are built into software/hardware by manufacturers/developers and are used to solve various problems, mainly collecting information for marketing purposes to increase profits and collecting global statistics to analyze the behavior of the masses of people in various parts of the globe.

Answer 3

No

Answer 4

It does not exist, since it is physically impossible to completely protect a "cell" of an integrated memory circuit from reading, then it could not be executed, it can only be limited at some software level, in general, it can only complicate the process.

Answer 5

Нет.
"Может ли всемогущий бог создать камень, который не сможет поднять?" (с)
Сиречь "раз некто такое ПО сделал, то сам-то он как-то должен оное обнаруживать.